DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration

49 CFR Parts 571 and 596
[Docket No. 98-3390, Notice 2]
RIN 2127-AG50

Federal Motor Vehicle Safety Standards;
Child Restraint Systems;
Child Restraint Anchorage Systems

AGENCY: National Highway Traffic Safety Administration (NHTSA), Department of Transportation.

ACTION: Final rule.

SUMMARY: This final rule establishes a new Federal motor vehicle safety standard that requires motor vehicle manufacturers to provide motorists with a new way of installing child restraints. In the future, vehicles will be equipped with child restraint anchorage systems that are standardized and independent of the vehicle seat belts.

The new independent system will have two lower anchorages, and one upper anchorage. Each lower anchorage will include a rigid round rod or "bar" unto which a hook, a jaw-like buckle or other connector can be snapped. The bars will be located at the intersection of the vehicle seat cushion and seat back. The upper anchorage will be a ring-like object to which the upper tether of a child restraint system can be attached. The new independent anchorage system will be required to be installed at two rear seating positions. In addition, a tether anchorage will be required at a third position. This final rule also amends the child restraint standard to require child restraints to be equipped with means for attaching to the new independent anchorage system.

This final rule is being issued because the full effectiveness of child restraint systems is not being realized. The reasons for this include design features affecting the compatibility of child restraints and both vehicle seats and vehicle seat belt systems. By requiring an easy-to-use anchorage system that is independent of the vehicle seat belts, this final rule makes possible more effective child restraint installation and will thereby increase child restraint effectiveness and child safety.

Issuance of this rule makes the United States the first country to adopt requirements for a complete universal anchorage system. To the extent consistent with safety, NHTSA has sought to harmonize its rule with requirements being considered by standard bodies and regulatory authorities in Europe and elsewhere. The agency has harmonized with anticipated Economic Commission for Europe and Canadian regulations by requiring that bars be used as the lower anchorages for installing child restraints. The agency has also harmonized with Canadian and Australian regulations by expressly requiring tether anchorages in vehicles and indirectly requiring tethers on most child restraints.

For the convenience of the traveling public, DOT wants child restraints complying with this final rule to be usable in both aircraft and motor vehicles to the extent practicable. To that end, the agency is developing a proposal to ensure that the new child restraints are not designed in a way that might make them unsuitable for aircraft use. NHTSA expects to issue the proposal this spring.

DATES: The amendments made in this rule are effective September 1, 1999.

The incorporation by reference of the material listed in this document is approved by the Director of the FEDERAL REGISTER as of September 1, 1999.

Petitions for reconsideration of the rule must be received by [INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES: Petitions for reconsideration should refer to the docket number of this document and be submitted to: Administrator, Room 5220, National Highway Traffic Safety Administration, 400 Seventh Street S.W., Washington, D.C., 20590.

FOR FURTHER INFORMATION CONTACT:

For nonlegal issues: George Mouchahoir, PhD. (202-366-4919), Office of Crashworthiness Standards, NHTSA.

For legal issues: Deirdre R. Fujita, Office of the Chief Counsel (202-366-2992), NHTSA.

Both of the above persons can be reached at the National Highway Traffic Safety Administration, 400 Seventh St., S.W., Washington, D.C., 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

1. Executive Summary of this Final Rule

1. Final rule
2. Why NHTSA is issuing this rule: the underlying issue, and how this rule corrects it
3. How and why this final rule differs from the agency's NPRM: particularly, why NHTSA selected the ISO rigid bar anchorage system, instead of the flexible latchplate anchorage system
4. Future proposal to promote the usability of the new child restraints in both aircraft and motor vehicles

2. Safety Issue

1. Why is something being done to improve child restraint safety? Aren't child restraints highly effective already?
2. Factors affecting child restraint effectiveness

3. Summary of the NPRM

1. What NHTSA proposed to address the issue; preference for flexible latchplate anchorage system over the rigid bar anchorage system
2. Proposed leadtime
3. NPRM's estimated benefits and costs of the rulemaking
4. Alternatives considered

4. Summary of the Comments

1. Commenters supporting flexible latchplate anchorage system
2. Commenters supporting rigid bar anchorage system

5. Summary of Post-Comment Period Events and Docket Submissions

1. ISO working group refines and completes draft ISO standard on rigid bar anchorage system
2. Child restraint manufacturers shift support to rigid bar anchorage system
3. Industry conducts consumer focus group testing on which lower anchorage system is preferred
4. d. Canada issues rule on tether anchorages

6. Agency Decision Regarding Final Rule

1. Summary of the final rule
2. Summary of key differences between NPRM and final rule

7. Issue-by-Issue Discussion of the Agency Decision on Content of Final Rule

1. NHTSA determines the anchorage systems are essentially equal on the merits
2. There is substantial consumer interest in both anchorage systems
3. NHTSA determines only one lower anchorage system can be selected
4. NHTSA selects the rigid bar anchorage system based on its advantages over the flexible latchplate anchorage system

1. The first advantage is harmonization of standards
2. The second advantage is enhanced design flexibility which provides a reasonably predictable prospect for design improvements that will enhance either safety or public acceptability or both
3. The third advantage is possible safety benefits

5. NHTSA's final rule is not identical to the draft ISO standard

1. Bars may not be attached to the vehicle by webbing materials
2. The bars must be visible or the vehicle seat back marked to assist consumers in locating them
3. A tether anchorage is not required by the draft ISO standard, but is required by this final rule

6. The types of vehicles that are subject to the adopted requirements
7. The number of anchorage systems that are required in each vehicle
8. Lockability requirement will be retained until 2012
9. Strength requirements for lower rigid bars of child restraint anchorage system and compliance test procedures
10. Requirements for child restraints
11. Performance and testing requirements for tether anchorages
12. Leadtime and phasing-in the requirements.

1. Tether anchorage and tether strap
2. Lower anchorage bars and means for attaching child restraints to those bars
3. Requirement to identify vehicles certified to the vehicle requirements during the phase-in

I. Executive Summary of this Final Rule

Child restraint systems are highly effective in reducing the likelihood of death or serious injury in motor vehicle crashes. The agency estimates that child restraints are potentially 71 percent effective in reducing the likelihood of death.⁽¹⁾ However, the extent to which this level of effectiveness is achieved in actual use depends upon a number of factors, including how well motorists are able to adapt the vehicle seat belts for the installation of the child restraints, and upon the compatibility between child restraints and vehicle seats and seat belts. As a result of improper installation of children in child restraints and child restraints in vehicles, the actual average effectiveness for all child restraints in use in preventing fatalities is 59 percent.⁽²⁾

This final rule will improve the actual average effectiveness of child restraint systems by improving the compatibility of child restraints and vehicles and making them easier to install. This rule requires that motor vehicles be equipped with a easy-to-use anchorage system designed to be used exclusively for securing child restraints. Each vehicle anchorage system will consist of an upper anchorage point and two lower anchorage points. Each lower anchorage includes a 6 millimeter (mm) (0.24 inches (in.)) diameter straight rod, or "bar," that is attached to the vehicle and is lateral and horizontal in direction. The bars are located near the intersection of the seat cushion and seat back in a position where they will not be felt by seated occupants. The upper anchorage is a user-ready component for attaching the top tether of a child restraint. This preamble refers to this system as the "rigid bar anchorage system," in reference to the 6 mm diameter bars, which are rigidly mounted to the vehicle.

Each vehicle must have at least two vehicle anchorage systems rearward of the front seat. However, if a vehicle has a rear seat with insufficient space to accommodate a rear facing infant seat, and is equipped with, as original equipment (OE), an air bag cutoff switch that deactivates the air bag for the front passenger position, one anchorage system must be provided in that position, and another in a rear seating position to accommodate a forward-facing child restraint.⁽³⁾ If a vehicle has no rear seat, and is equipped with an OE air bag cutoff switch that deactivates the air bag for the front passenger position, one anchorage system must be provided in that position.

Each vehicle with at least three rear designated seating positions must also have a third rear designated seating position equipped with a user-ready tether anchorage. The third tether anchorage provides parents an improved means of attaching the new child restraints at a third rear seating position. In a typical family car with three rear seating positions, the third tether anchorage would likely be at the center rear seating position, which is a seating position that many parents prefer placing their child. A full child restraint anchorage system (consisting of the two rigid bars for the lower anchorages and a top tether anchorage) is not required to be installed in the center rear seating position because it may be difficult to fit the lower anchorages of two child restraint anchorage systems, or two child restraint systems, adjacent to each other in the rear seat of small vehicles. Further, a lap belt at the center rear seating position, together with a tether anchorage at that position, should perform essentially as well as a full child restraint anchorage system. For these reasons, and to minimize the cost of facilitating the use of the new child restraints in the third position, the agency is requiring two, and not three, child restraint anchorage systems.

Each child restraint will have components, such as hooks or buckles, that are designed to clasp to the two lower rigid bars of a vehicle's rigid bar anchorage system. Although the final rule does not expressly require child restraints to have top tethers, it establishes stricter limits on the distance that the head of a dummy seated in a child restraint may move forward during a test simulating a frontal vehicle crash (head excursion limit). Almost all child restraint models will likely be equipped with a top tether in order to comply with the new head excursion limit.

Each child restraint will also have to continue to be capable of being attached to a vehicle by way of the vehicle's belt system. This way, child restraints that have the new components can still be used on older model vehicles that do not have a child restraint anchorage system. Child restraints with the new components can also still be used on aircraft, using the aircraft belt system to attach to the aircraft seat. Older model child restraints that do not have the new components attaching to the child restraint anchorage system can use vehicle belts, as child restraints do now, to attach to new vehicle seats that have a child restraint anchorage system.

The requirements adopted today reflect a worldwide effort to improve the installation of child restraints in motor vehicles. This final rule uses the technical specifications set forth in a draft standard being developed by a working group to the International Organization for Standardization (ISO), a worldwide voluntary federation of ISO member bodies. NHTSA anticipates that the ISO, which began work on an independent child restraint anchorage system in the early 1990's, will be adopting the draft standard as a final standard within the next year. Incorporation of the ISO standard into the regulations of the European community is likely to follow. Canada and Australia have also indicated their intent to undertake regulatory action aimed at requiring the rigid bar anchorage system to improve child restraint attachment for their countries' children.

NHTSA is issuing this final rule at this date, prior to the ISO's completion of work on the draft standard, in order to provide increased safety to this country's children as quickly as possible. Further, the agency anticipates that the ISO and the working group will not make significant changes to the draft ISO standard. To the extent that the final ISO standard differs from this final rule, the agency will evaluate those differences to determine if changes to this final rule appear warranted. In the event NHTSA tentatively determines that changes may be warranted, the agency will commence a rulemaking proceeding and make a decision as to the issuance of an amendment based on all available information developed in the course of that proceeding, in accordance with statutory criteria.

This rule makes it easier to install child restraints by eliminating the current dependence of motorists on vehicle seat belts as the means of installing child restraints in vehicles. The primary purpose of seat belts has always been to protect older children, teenagers and adults from serious injury in vehicle crashes. A secondary purpose of seat belts has been to install child restraints in vehicles.

Attempting to design seat belts to achieve the first purpose (restraining older children, teenagers and adults) has sometimes led to design choices that may have made it more difficult for the belts to achieve the second purpose (tightly securing a child restraint). One design change is the replacement of simple lap belts with integrated lap/shoulder belts in the back seats of vehicles. Another change is the positioning of some seat belt anchorages several inches forward of the seat back to better position the lap belt low on the pelvis of these occupants. While these and other design changes have increased the ability of vehicle belt systems to restrain occupants, they have made it harder for motorists to use the belts on some vehicles for installing child restraints.

By requiring motor vehicles to be equipped with standardized anchorages designed exclusively for the purpose of securing child restraints, this final rule will help vehicle and seat belt manufacturers design belts to more effectively perform a dual role. Manufacturers will be able to optimize seat belts to restrain older children, teenagers and adults. Further, the final rule will provide motorists with a means of securing child restraints that is easier and more effective.

By requiring an independent child restraint anchorage system, the final rule improves the compatibility of vehicle seats and child restraints and the compatibility of seat belts and child restraints. Installation of the new system will result in more child restraints being correctly installed. The standardized vehicle anchorages and the means of attachment on child restraints are intuitive and easy-to-use. For example, they eliminate the need to route the vehicle belt through or around the child restraint. By making child restraints easier to install, correct use and effectiveness will be increased.

The requirement for top tether anchorages in vehicles will be implemented before the requirement for the lower vehicle anchorages since less leadtime is needed for the installation of the tether anchorages. In those vehicles equipped with tether anchorages but not lower anchorages, owners can install a child restraint complying with this rule by attaching the tether and using the vehicle seat belts to secure the lower part of the child restraint. Tether anchorages will be required in the vast majority of passenger cars beginning September 1, 1999⁽⁴⁾, and in all light trucks, buses and multipurpose passenger vehicles beginning September 1, 2000. To provide consumers with the standardized lower anchorages in vehicles as quickly as possible, this rule specifies a three year phase-in that begins September 1, 2000. Beginning on that date, this rule requires vehicle manufacturers to begin installing the new lower anchorages in new passenger cars, in trucks and multipurpose passenger vehicles with a gross vehicle weight rating (GVWR) of 3,856 kilograms (kg) (8,500 lb) or less, and in buses with a GVWR of 4,536 kg (10,000 lb) or less (including school buses in that GVWR category). Beginning on September 1, 2002, the new lower anchorages will be required in all new vehicles in those categories.

The requirement (the stricter head excursion limit) that will cause top tethers to be installed on most child restraint systems will be effective September 1, 1999. The requirement for child restraints to be equipped with means for attaching to the lower anchorages will be effective September 1, 2002. NHTSA believes that the latter requirement should not be phased-in. Child restraint manufacturers have informed the agency that a phase-in would not be successful because they do not have the same type of control over the distribution of their products that vehicle manufacturers have. According to the child restraint manufacturers, if they were to produce both current child restraint systems as well as child restraints with the new attachments, distributors and retailers of their products would order mainly the current child restraints to sell, which do not have the new attachments, and not the new restraints because the current systems would cost less than the new child restraint systems. Further, NHTSA has decided against requiring all new child restraints to have the new attachments earlier than the date on which vehicles will be equipped with the lower anchorage system because new vehicles equipped with the new attachment system will be a small proportion of the total vehicle fleet during the phase-in period. Nevertheless, the agency anticipates that some child restraint manufacturers will begin offering new designs during the phase-in period, to meet a market demand for the products.

Today's final rule adopts the key aspect of the proposal. As in the proposal, this rule requires vehicles to be equipped with an independent anchorage system for attaching child restraints. An independent system is strongly preferred by consumers over current seat belts as the means of attaching child restraint systems. The independent system uses three attachment points for securing a child restraint to a vehicle seat (the two lower anchorages and the top tether). The two lower points are at or near the intersection of the vehicle seat cushion and seat back.

However, this final rule differs from the proposed system in several important respects. The agency proposed to permit either of two lower anchorage systems for vehicles: (1) the rigid bar anchorage system adopted in this final rule; or (2) a buckle and flexible latchplate system known as "the uniform child restraint anchorage system" ("UCRA" system). The buckle and latchplate of the second system are similar to what is used for adult seat belts in vehicles. The two lower anchorages consist of small latchplates, attached to flexible webbing, near the intersection of the vehicle seat cushion and seat back. (In reference to the latchplates and to the flexibility of the webbing, hereinafter this preamble refers to the UCRA system as the "flexible latchplate system." This is to provide a more descriptive term for the system than "UCRA," for the reader's convenience.) Buckles designed to attach to the latchplates are attached to the child restraint by belt webbing.

Both systems would have been permitted under the NPRM because each had its advantages. At the time of the proposal, information available to NHTSA indicated that the installation of the flexible latchplate system, instead of the rigid bar anchorage system, in motor vehicles would result in less added cost and weight for child restraints. This information was contained in a study performed by a contractor for NHTSA. At the time of that study, the then-existing prototypes of child restraints made to connect with the rigid bar anchorage system were significantly different from current prototypes. The then-existing prototypes typically had rigid prongs, or runners, for attaching the child restraints to the rigid bars and a substantial (and therefore heavy) supporting structure for the runners. Based on that information from the study, the agency's cost analysis indicated that the buckles of the flexible latchplate system (which were attached to the child restraint by means of webbing) would add an estimated $14 to the cost of a child restraint, while the rigid prongs (attached by means of a heavy base) would add $60 to $100 to the cost of a child restraint.

Although the two systems appeared to have similar safety benefits, the lower anchorage of the flexible latchplate system appeared to necessitate making less costly changes to child restraints than the rigid bar anchorage system. Accordingly, the agency gave preference to the flexible latchplate system in its proposal. It did this by proposing to require that all child restraints have the buckles for attaching to the flexible latchplate system. The rigid bar anchorage system could have been provided only if the vehicle manufacturer also provided an adapter that would connect at one end to the rigid bar and at the other end to the buckles on the child restraint.

The agency has decided to require the installation of rigid bar anchorage systems in motor vehicles instead of permitting either those systems or flexible latchplate anchorage systems. Commenters urged NHTSA to mandate a single system because of their opposition to an adapter. They believed that an adapter would be lost or misused by consumers, resulting in buckle-equipped child restraints unable to use or improperly using a rigid bar anchorage system in the vehicle. Further, the agency notes that mandating a single system standardizes the anchorage system and thereby promotes consumer understanding of and familiarity with the system.

In deciding which system to select, NHTSA noted that the rigid bar anchorage system and the flexible latchplate system appear to be roughly equally acceptable to the public. ISO-reported consumer clinics that were conducted overseas and in Canada indicated comparable levels of consumer acceptance for the two systems. In the most recent consumer preference clinic, which was sponsored by U.S. and foreign vehicle manufacturers, child restraint designs that were compatible with the rigid bar anchorage system and with the flexible latchplate system were strongly preferred over current child restraints designs that use vehicle seat belts to attach to the vehicle. While consumers scored the child restraint design that had the buckles highest, the three systems that had the rigid bar anchorage-type of child restraints were, in aggregate, the first choice of a large number of participants. This does not mean that the consumers selected the rigid bar over the flexible latchplate as their preferred vehicle system. However, it does appear to indicate that the design flexibility of the rigid bar system accommodated a variety of child restraint attachment options that, in aggregate, resulted in more "first place" finishes than the flexible latchplate design.

The agency also noted that when the flexible latchplate lower anchorage system is compared to new prototypes of child restraints designed to attach to rigid anchorages, the flexible latchplate system loses much or all of the cost and weight advantage it was thought to have at the time of the NPRM. After the NPRM was published, a number of child restraint and vehicle manufacturers determined that child restraints need not have rigid runners to attach to the rigid bar anchorage system. They told the agency that hooks and other devices were viable alternatives to rigid runners, and would be used by most child restraint manufacturers if the rigid bar anchorage system were adopted. They said that the hooks and other alternative connectors could be attached to the child restraint with belt webbing, in the same way the buckles for the flexible latchplates can be attached to the child restraint. New analysis by the agency indicates that these alternative rigid bar anchorage connectors would cost about the same or less than the flexible latchplate buckles, and would not add substantial bulk or weight to child restraints.

The rigid bar anchorage system currently has fairly wide support among both vehicle and child restraint manufacturers. In June 1996, the flexible latchplate anchorage system was supported by a wide variety of vehicle manufacturers (virtually all domestic and foreign vehicle manufacturers except for European manufacturers) and child restraint manufacturers. Now, however, the only major vehicle manufacturer on record with this agency as expressly favoring the flexible latchplate anchorage system is General Motors. The shift to the rigid bar anchorage system began shortly before publication of the NPRM. At that time, Ford and Chrysler announced that they had changed their support to the rigid bar anchorage system. Recently, Toyota expressed support for the rigid bar anchorage system. In addition, most child restraint manufacturers now support the rigid bar anchorage system.

Manufacturers cited the potential advantages of the rigid bar anchorage system over the flexible latchplate system. They believe that the rigid bar anchorage system will further international harmonization of safety standards, while the flexible latchplate system will not. They also believe that the rigid bar anchorage system allows for greater design flexibility than the flexible latchplate system in the design of child restraints and the connectors used to attach to the anchorage system. They also believe that the rigid bar anchorage system will enhance safety better than the flexible latchplate system in side impacts, when rigid attachments are used on the child restraint to connect to the rigid 6 mm bars in the vehicle seat bight (the intersection of the seat cushion and the seat back). Many supporters of the rigid bar anchorage system cite test data that show that the system prevented head contact between a test dummy and the door structure in side impact simulations, while the flexible systems did not. Some child restraint manufacturers also believe that rigid attachments on both the vehicle and the child restraint could better limit head excursions of older children in frontal impacts.

NHTSA's selection of the rigid bar anchorage system harmonizes this final rule with the actions of other regulatory authorities around the world. Further, today's final rule adopts best practices in what has been a global effort to develop an effective and easy-to-use child restraint anchorage system. The rigid bar anchorage system is the one most likely to be chosen as an internationally harmonized design under the auspices of the United Nations Economic Commission for Europe. Canada is also in support of the rigid bar anchorage system and may be adopting the system in the future. This final rule also harmonizes with Canadian and Australian regulations by expressly requiring tether anchorages in vehicles and indirectly requiring tethers on most child restraints.

Harmonizing this rule with the actions of other international bodies is consistent with the goals of the Trade Agreements Act of 1979, as amended (July 26, 1979, Public Law 96-39, section 1(a), 93 Stat. 144.) (19 U.S.C. 2501 et seq.). That Act requires, inter alia, Federal agencies to take into consideration international standards and, if appropriate, base the agencies' standards on international standards.  The harmonization achieved by this rule permits vehicle and child restraint manufacturers to have a greater measure of planning certainty and predictability in designing and selling their products, helps ensure that parents are provided an anchorage system that meets their safety needs at the lowest possible cost, and eliminates a potential barrier to international trade.

As NHTSA noted in its February 1997 NPRM, the Federal Aviation Administration (FAA) is concerned that some new child restraints might be manufactured with rigid ISO connectors or prongs that are neither foldable nor retractable. FAA believes that if a child restraint with non-folding, non-retracting rigid connectors were installed on an aircraft seat, the connectors or prongs might damage the aircraft seat cushions. They could also protrude into the leg space and egress path of the passengers sitting in the row immediately behind the seat.

NHTSA believes that the near-term prospect of child restraint manufacturers producing child restraints with non-folding, nonretractable rigid connectors is fairly remote. Most child restraint manufacturers are not using rigid connectors in their prototype development work. The one manufacturer focusing on rigid connectors has been using retractable rigid connectors or prongs in its product development work.

Nevertheless, the issue of child restraint/aircraft compatibility and consumer convenience is an important concern to NHTSA and FAA. The two agencies want parents to be able to buy a single child restraint that can be used in aircraft as well as in motor vehicles. To that end, NHTSA is developing a proposal to ensure that the new child restraints are not designed in a way that might make them unsuitable for aircraft use. The proposal would require that if a child restraint has rigid connectors, they must be foldable or retractable. As an alternative, the agency would propose to require foldability or retractability as a condition to certifying child restraints with rigid connectors for aircraft use. NHTSA expects to issue the proposal this spring.

II. Safety Issue

NHTSA estimates that, when installed correctly in a vehicle with compatible seating and seat belt systems, child restraints are 71 percent effective in reducing the likelihood of death in motor vehicle crashes. However, as a result of many child restraints either not being used correctly or installed in vehicles with seats or seat belts that are not fully compatible, the actual average effectiveness for the entire population of child restraints in use is 59 percent.⁽⁵⁾

The estimated 71 percent level of effectiveness is not realized in many cases for several reasons. Currently, the standardized means of attaching a child restraint is the vehicle belt system. Over the years, vehicle seats and belt systems evolved to better restrain the upper and lower torsos of older children, teenagers and adults. For example, seat belt anchorages are sometimes positioned several inches forward of the seat back to better position the lap belt low on the pelvis of these occupants. The need to design vehicle seat belts to perform the dual functions of restraining child restraint systems and of restraining the torsos of older children, teenagers and adults limits the extent to which vehicle belts can be designed to promote the effectiveness of child restraints.

To elaborate further on the example given above regarding seat belt anchorages, when vehicle belts attached to forward-mounted seat belt anchorages are used with a child restraint, the belts cannot initially provide any resistance to the forward movement of a child restraint in a frontal crash. The child restraint slides forward in a crash until the belt finally resists the forward movement of the child restraint. NHTSA estimates that seat belt anchorages positioned five or more inches forward of the seat back can increase the probability of severe or greater injury by over 11 percent. This final rule makes child restraints safer by reducing the likelihood of increased forward movement of the child's head, and the likelihood of head impact, and other traumas.

Other examples of the need to improve the compatibility of child restraint systems and vehicles include:

(1) The seat cushions and seat backs are deeply contoured. This improves the comfort of seated passenger and helps keep belted passengers in place, but limits the ability of the seat to provide a stable surface on which the child restraint can rest. This final rule will make child restraints more stable, regardless of the contours of the seat and seat back.

(2) The length of some seat belts and accompanying hardware attachments are not suitable for use with child restraints, or with special child restraints. In some seating positions, the distance between the anchorages for the lap belt and buckle is not as wide as a child restraint. In these cases, the seat belt may not tightly hold the child restraint and it can easily move from side to side. By providing a means for attaching child restraints that is independent of the vehicle belts, this final rule will improve the lateral stability of child restraints on the vehicle seat.

(3) Some vehicle seats are not wide enough or long enough to accommodate child restraints properly. This final rule will accommodate child restraints on these seats by providing an independent means of stability.

Efforts to make vehicle belt systems more effective for teenagers and adults have also resulted in the belt systems becoming more complex. Lap/shoulder belts replaced lap belts. On older vehicles, these belts need to be used with an accessory item, such as a locking clip, for use with child restraints. A locking clip impedes movement of the sliding latchplate on the lap/shoulder belt, which better restrains a child restraint when the car is maneuvering or changing its velocity. Since September 1, 1995, lap belts on new passenger vehicles are lockable without a locking clip, but the belt must be maneuvered in a special manner not always understood by consumers to engage the locking feature.

Due in part to these complexities, the rate of incorrect usage of child restraints is high. A four-state study done for NHTSA in 1996 examined people who use child restraint systems and found that approximately 80 percent of the persons made at least one significant error in using the systems. ("Patterns of Misuse of Child Safety Seats," DOT HS 808 440, January 1996.) Observed misuse due to a locking clip being incorrectly used or not used when necessary was 72 percent. Misuse due to the vehicle seat belt being incorrectly used with a child seat (unbuckled, disconnected, misrouted, or untightened) or used with a child too small to fit the belts was 17 percent.

People are not only not using child restraints as correctly as they should, they are also frustrated with the effort needed to attach a child restraint. Consumer clinics conducted in the U.S.⁽⁶⁾ and Canada⁽⁷⁾ found that virtually all the people surveyed in the studies expressed high levels of dissatisfaction with conventional means of attaching child restraints in vehicles. NHTSA's Consumer Complaint Hotline received approximately 19,792 calls in 1996, 10,326 calls in 1997, and 19,935 in eight months in 1998, from people asking about child seat compatibility with a particular vehicle or how to correctly install a child seat, including requests for step-by-step guidance in installing their child seats. When an article appears in the media about compatibility problems between child restraints and vehicle seats, those calls typically increase to over 500 a day.

NHTSA is concerned that because of frustrations associated with vehicle to child restraint compatibility problems and the difficulties with installing child restraints, consumer confidence in the safety of child restraint systems could be eroding. A consumer clinic held in April 1998 showed that the number one consumer safety concern was with how tightly (secure) participants could get the child restraint installed in the vehicle. NHTSA estimates that about 35 percent of the rear seats of new passenger cars having seat belt anchorages 4 inches or more away from the seat bight. The agency is concerned that declining consumer confidence in child restraint systems could result in less use of child restraints. Being able to tightly secure a child restraint by way of an independent child restraint anchorage system provides consumers with confidence in child restraint safety and has the most potential for the highest, most effective, use of child restraints.

As a result of the usage and compatibility problems affecting the installation of child restraint systems in vehicles, NHTSA proposed that vehicles should be required to have a standardized system for attaching child restraints that was independent of the vehicle belts. On February 20, 1997, NHTSA published an NPRM proposing to require vehicles to have an independent "child restraint anchorage system" installed in two rear designated seating positions (in vehicles with two or more rear seating position) and to require child restraints to be equipped with a means of attaching to that system (62 FR 7858).⁽⁸⁾

A "child restraint anchorage system" was defined to consist of two lower child restraint anchorages at the seat bight and a tether anchorage for attaching a top tether strap of a child restraint system. The lower anchorages could consist of either flexible latchplates or rigid bar anchorages. However, NHTSA considered the flexible latchplate anchorage system to have cost and weight advantages over the rigid bar anchorage system, so the agency favored the flexible latchplate anchorage system by (1) requiring all child restraints to have buckles for the flexible latchplates and by (2) requiring each vehicle having rigid bar anchorages to provide adapters that could accommodate child restraints with the buckles for the flexible latchplates. At the time of the NPRM, Canada was also undertaking rulemaking to require user-ready tether anchorages and NHTSA sought to harmonize with those prospective requirements. (Canada has since adopted its proposal for the tether anchorages. See, section V.d., infra.) The agency's NPRM also proposed reducing allowable head excursion limits in the Federal safety standard regulating child restraint systems, Standard 213, which would have had the effect of requiring most, if not all child restraints to be equipped with an upper tether strap.

The NPRM proposed requirements to specify the construction of the child restraint anchorage system, the location of the anchorages, and the geometry of related components, such as the hardware that attaches to a child seat. To prevent the vehicle anchorages from failing in a crash, the anchorages, including structural components of the assembly, would have had to withstand specified loads in a static pull test.

NHTSA proposed applying the requirement for the flexible latchplate system to all passenger cars, and all trucks, buses and multipurpose passenger vehicles (MPVs) with a gross vehicle weight rating (GVWR) of 4,536 kg (10,000 lb) or less. Each vehicle would have had to have at least two flexible latchplate anchorage systems rearward of the front seat. If a vehicle had no rear seat or had insufficient space to accommodate a rear facing infant seat, and were equipped with an air bag cutoff switch, as original equipment (OE), that deactivates the air bag for the front passenger position, one anchorage system would have had to be provided in that position, and another in a rear seating position to accommodate a forward-facing child restraint. A built-in child seat could have been substituted for one of the systems, but not both, since rear-facing built-in systems are currently unavailable. If there were no switch to turn off the front passenger air bag, installation of an independent anchorage system would not have been permitted in the front passenger seat.

NHTSA believed that the user-ready tether anchorage requirement for vehicles could be made effective at a much earlier date than a requirement for the lower anchorages of the child restraint anchorage system. This was, in part, due to the fact that vehicles already had a tether anchorage structure (e.g., a reinforced hole) at rear seating positions to satisfy current Canadian requirements. The NPRM proposed that the tether anchorage requirement become effective September 1, 1999 for passenger cars and a year later for LTVs. These effective dates were the same ones proposed by Canada for its user-ready tether anchorage requirement. The NPRM proposed that the effective date for reducing Standard 213's head excursion requirement, thereby requiring a tether for most child restraints, would be September 1, 1999.

The agency sought comments on whether a phase-in requirement for the lower anchorages in vehicles would be appropriate, and how long a period is needed for full implementation of the requirement. Comments were also requested on the appropriateness of phasing-in the requirement that child restraints be equipped with the devices that connect to the vehicle child restraint anchorage system.

The NPRM discussed the agency's tentative conclusions about the impacts (e.g., costs and benefits) of a final rule. The annual benefits of the rule were estimated to be 24 to 32 lives saved, and 2,187 to 3,615 injuries prevented.

The NPRM estimated the average cost of a rule requiring the flexible latchplate anchorage system would be approximately $160 million. The cost of the rule for vehicles was estimated to be about $105 million. The cost of the rule related to the vehicle would range, per vehicle, from $3.88 (one flexible latchplate anchorage system in front seat only) to $7.76 (for one flexible latchplate anchorage system in front seat and one in back seat or two flexible latchplate systems in rear seats). NHTSA estimated that 15 million vehicles would be affected annually: 9 million passenger cars and light trucks with "adequate" rear seats, 3 million vehicles with no rear seat, and 3 million vehicles that can only accommodate a forward-facing child seat in the rear seat (not a rear-facing infant seat). The cost of the buckle attachments on the child seat was estimated to be about $55 million (3.9 million child restraints (excluding belt-positioning boosters) at $14 per seat.) The rigid bar anchorage system was thought to increase the cost of a child restraint by possibly $100, assuming that the child restraint had to have rigid attachments and a heavy structure to support those attachments.

The agency considered and tentatively rejected several alternatives to an independent child restraint anchorage system. Efforts to improve compatibility of child restraint systems and vehicle interior designs first focused on the extent to which vehicle seats and seat belt systems could better perform their dual functions of attaching child restraints and protecting adults, teenagers and older children. The agency evaluated what the industry had developed by way of design tools that would help optimize protection for both the restrained child and older population groups.

The Society of Automotive Engineers' (SAE) Recommended Practice SAE J1819, "Securing Child Restraint Systems in Motor Vehicle Rear Seats," specifies guidelines that vehicle and child restraint manufacturers can use for designing their products with compatibility in mind. The recommended practice specifies a common reference tool, a "Child Restraint System Accommodation Fixture," that both vehicle manufacturers and child restraint manufacturers can use in assessing compatibility. In addition, J1819 provides design values to vehicle manufacturers for certain characteristics of rear seats and seat belts, such as seat cushion shape and stiffness, and seat belt anchorage location, belt length, buckle and latchplate size, and lockability. Likewise, J1819 provides design guidelines to child seat manufacturers for child seat features that correspond to the vehicle features.

NHTSA believed that requiring compliance with J1819 alone would not sufficiently improve compatibility. Most, if not all vehicle and child restraint manufacturers already use J1819 when designing their products. Requiring compliance with J1819 also seemed excessively design restrictive for both vehicle and child restraint manufacturers. It would perpetuate the difficulties vehicle manufacturers have in designing their belts for the dual function of protecting both the child restraint occupant and the adult.

Another approach that NHTSA had taken to improve compatibility was to improve the belt system to specifically require a feature to improve the belt's usefulness with a child restraint system. For vehicles produced beginning in September 1995, NHTSA added a "lockability" requirement to the occupant crash protection standard (Standard 208). The rule requires the lap belt to be lockable to tightly secure child safety seats, without the need to attach a locking clip or any other device to the vehicle's seat belt webbing (58 FR 52922, October 13, 1993).

While the lockability requirement ostensibly makes a locking clip obsolete, it still depends on the user knowing enough and making the effort to manipulate the belt system.⁽⁹⁾ Also, the vehicle belt must be routed correctly through the child restraint, which may not be an easy task in all cases. Further, the lockability requirement does not address the effects of forward-mounted seat belt anchorages on child restraint effectiveness.

It became apparent that what was needed was for the vehicle system that secured the child restraint system to be independent of the vehicle system that restrained and protected the adult, teenager and older child. This idea originated in Europe where work on a child restraint anchorage system quickly evolved, most notably in the technical committee of the International Organization for Standardization (ISO).

Cosco, a child restraint system manufacturer, suggested an independent child restraint anchorage system that is midway between using the vehicle's belts to attach a child restraint and the child restraint anchorage system developed by groups such as the ISO and adopted today by this final rule. Cosco's "car seat only" (CSO) system, consists of an independent lap belt that is installed in vehicle seats separately from the integrated lap/shoulder belts provided for adult passengers. Similar to other child restraint anchorage systems such as the ISO rigid bar system or GM's flexible latchplate system, the CSO is independent of the vehicle's current belt system. Yet, the CSO still uses the design concepts associated with a belt system, e.g., using a belt to wrap through or around the child restraint to latch it into the vehicle. To Cosco, that is the appeal of its system. Cosco believes that the CSO system would not require any changes in the design and manufacture of child restraints and thus would add no increase to the price of child restraints.

To NHTSA, the fact that the CSO system is essentially no different from the historic lap belt means the dissatisfaction many consumers have about the difficulty of attaching a child restraint is likely to be perpetuated with the CSO. NHTSA was concerned that the CSO system might not make attaching a child seat significantly easier than it is today. To NHTSA, a new means of attaching child restraints had to be explored. Commenters responding to the NPRM agreed.

NHTSA received over 70 comments in response to the rulemaking proposal.⁽¹⁰⁾ Because the international community is considering adoption of a standard for a universal, independent child restraint anchorage system, the agency received submissions from foreign governments as well as domestic entities. All commenters agreed with the need for a universal, independent child restraint anchorage system and overwhelmingly concurred with the proposed requirements for a top tether anchorage. However, over half opposed the agency's choice of the flexible latchplate system over the rigid bar anchorage system for the lower anchorage points.

The tentative choice of the flexible latchplate system was supported by the Michigan Department of State Police, the Automotive Occupant Restraints Council, General Motors (GM), Advocates for Highway and Auto Safety (Advocates), Indiana Mills and Manufacturing Inc. (IMMI), the Drivers' Appeal for National Awareness (DANA), Gerry Baby Products, and Evenflo Company.⁽¹¹⁾ (Gerry and Evenflo have since consolidated into one child restraint system manufacturing company.) Several members of Congress sent a letter supporting the flexible latchplate system.⁽¹²⁾ 

Proponents of the flexible latchplate anchorage system agreed with the agency's tentative conclusions in the NPRM that the flexible latchplate system appeared to be superior to the rigid bar anchorage system because a child restraint equipped with buckles to attach to the flexible latchplates would be less costly, bulky and heavy than a child restraint equipped with rigid attachments. Some commenters supported the flexible latchplate system because they believed that it needs a shorter leadtime for implementation. IMMI, which helped develop the flexible latchplate and buckle, believed that the appeal of its buckle is that it provides a simple, intuitive, easy to use, and familiar hardware concept which will give consumers "a true sense of security and familiarity that will translate into more [child] seats being used as well as installed correctly."

Some of the proponents of the flexible latchplate system objected to the rigid bar anchorage system. Based on its belief that there is no buckle that can latch to a round bar, and therefore that such a buckle would have to be developed, IMMI suggested that the rigid bar anchorage alternative would take three to five times as long to implement. IMMI was also concerned that, under the specifications now under consideration by the ISO working committee developing the draft standard for the rigid bar system, the 6 mm bar would be permitted to be located up to 70 mm (2.75 inches) rearward of the seat bight. The commenter believed that locating the bars 70 mm from the seat bight would seriously jeopardize their visibility and/or accessibility. A letter "strongly opposing the round bar interface" was submitted by Century Products, Gerry Baby Products, Evenflo Company, Kolcraft Enterprises, and IMMI.⁽¹³⁾ The manufacturers stated that the rigid bar anchorage system is unacceptable, arguing that the

Rigidly mounted bars would not be visible or accessible inviting misuse or non-use of car seats. No specifications or technology exists for attachment connections to the round bar, and there is no guarantee that these connectors could be available in three to five years or be cost effective.

They were also "concerned for the long term liability and risk associated with use and performance on rigid systems designed to be used with the 6 mm bar."

The agency's proposal for making the flexible latchplate system the preferred system was opposed by the United Nations Economic Commission of Europe Group of Rapporteurs for Passive Safety (GRSP), the UK Parliamentary Advisory Council for Transport Safety, the UK Department of Transport, Transport Canada, the New South Wales Roads and Traffic Authority (Australia), Ford Motor Company, Chrysler Corporation, BMW of North America, Mercedes-Benz of North America, Volvo Cars of North America, Insurance Institute for Highway Safety (IIHS), Kathleen Weber of the University of Michigan Child Passenger Protection Research Program (UMCPP), Volkswagen of America, Fisher-Price, Britax Romer, the Millenium Development Corporation, Transport Research Laboratory Ltd. (TRL), Safe Ride News, SafetyBeltSafe, and the University of Kansas Medical Center. The commenters disagreed with the agency's tentative conclusions in the NPRM that the rigid bar anchorage system will be more costly and will add more weight and bulk to child restraints than the flexible latchplate system, and will likely need a longer leadtime to implement. They believed the rigid bar anchorage system and the flexible latchplate system will have similar cost, weight and leadtime impacts when the components that attach to the rigid bars are attached to a child restraint by webbing (some call this type of attachment a "non-rigid attachment," versus a rigid attachment). The commenters further believed that the rigid bar anchorage system is superior because it allows for more design flexibility in what child restraint manufacturers can use to connect their child restraints to the rigid bars; has greater potential safety benefits (for child restraints equipped with rigid attachments) by reducing head excursion in side impacts and by eliminating the need for the parent to tighten belts; and enhances international harmonization of safety standards.

Several commenters stated that the agency's preference for the flexible latchplate system was based on faulty premises, such as the suggestion that hardware interfacing with the rigid bars will not be available in the near future (commenters identified tether hooks as an available, low-cost hardware); and that consumers are more familiar with buckles and latchplates than with an rigid bar anchorage connector. BMW stated that because both the flexible latchplate and rigid bar anchorage systems permit the use of non-rigid attachments on child restraint systems, BMW said there is no cost penalty associated with the latter. The commenter stated that buckles for both the latchplate and the rigid bar interfaces will have virtually the same cost in production quantities. Also, BMW believed that the rigid bar anchorage system could be implemented virtually as quickly as the flexible latchplate design, and within the same leadtime. The Insurance Institute for Highway Safety (IIHS) believed that buckles designed to attach to the rigid bars may cost as little as $1.10 and can be designed and produced in less than one year. As for vehicle costs, VW believed that the rigid bar anchorage system would be less expensive for vehicle manufacturers than the flexible latchplate system. (VW cited NHTSA's October 17, 1996 cost analysis which estimated vehicle costs for the flexible latchplate system to be $11.62, and for the rigid bar system, $7.55.)

Several commenters believed an area where the rigid bar anchorage system is superior to the flexible latchplate system is with regard to the design flexibility of the systems. Kathleen Weber stated that "The [UCRA] flat plate, which can only be manifested in a soft-supported, protruding configuration, is a short term expedient that offers little opportunity for future design improvement." Similarly, BMW believed that the flexible latchplate system-

effectively freezes the current CRS technology....[T]he U.S. public will be forced to endure a system that does not have the flexibility to provide both low cost child restraint systems (with soft attachments) and advanced child restraints with enhanced side impact protection and self-tensioning devices.

Many commenters, including Ford, Volvo, IIHS, the Roads and Traffic Authority (RTA) of New South Wales (Australia) and others, believed that the rigid bar anchorage system is superior to the flexible latchplate system with respect to safety. Ford Motor Company believed that the rigid bar anchorage system would increase child restraint safety over the flexible latchplate system, particularly in side impact crashes, at nearly equivalent cost for child restraint and vehicle manufacturers. RTA stated that, while there is very little difference in frontal crash protection provided by child restraints attached by a flexible latchplate system and by the rigid bar anchorage system, "[t]he real differences show up when you conduct side impact tests. The rigid CANFIX/CAUSFIX⁽¹⁴⁾ system appears to offer considerable improved performance over the UCRA system and the current Australian attachment system [lap belt and tether]." The Department of Transport in the United Kingdom stated that "[w]e fully support the adoption of rigid [6 mm diameter bar] anchorages believing that they will simplify the fitting of CRS, significantly reduce the misuse of CRS, and offer improved dynamic safety performance." The commenter expressed concern that the flexible latchplate and the rigid bar are not compatible with respect to their interfaces and that the flexible latchplate system "does not offer the possibility of a transition to the rigid bar anchorage and the performance advantages it [the rigid bar system] offers."

Several commenters also believed that the rigid bar anchorage system would enhance child restraint safety in areas other than side impacts, as well. Safe Ride News stated that a rigid bar anchorage system using rigid attachments on the child restraint would minimize misuse by permitting a simple, one-click installation that virtually eliminates adjustment problems. Similarly, IIHS believed that the rigid system (for both vehicle and child restraint system) has the advantage of not requiring parents to tighten any belts. "Failure to tighten belts sufficiently is a common mistake parents make when using the current child restraint systems...."

Some commenters expressed concerns about potential safety problems with the flexible latchplate system. In commenting in support of the rigid bar anchorage system, Transport Research Laboratory Ltd. (TRL) stated that "A rigid attachment system [on both the vehicle and the child restraint] offers significant advantages over the soft systems in terms of ease of use and reduction in misuse. A soft attachment system, such as that proposed, while giving good performance when well tightened, will not give good performance when used as user trials suggest they will be used." (The commenter did not elaborate on this issue.) Volvo expressed a concern that "the compressive forces and bending moments resulting from both handling of the CRS and a crash situation may give rise to excessive stresses and strains in the [flexible latchplate]. This is less likely with the round ISOFIX⁽¹⁵⁾ attachments." (The commenter did not elaborate on this issue.) Volvo also stated that "[i]n a test Volvo has performed using the UCRA attachment there have been incidents of unintentional unlatching of the latchplate due to the release button on the latchplate being too close to the adjust seat belt buckle." The commenter also stated that the UCRA latchplates may not be accessible for foldable seats after folding and unfolding the seat backs and seat cushions. IIHS also stated that "using similar technology [to conventional seat belt buckles, as with the UCRA system] is not necessarily advantageous. In user trials, some consumers attempted to use the conventional seat belt latches to attach child seats rather than the designated child restraint latches in vehicles...."

Almost all of the commenters supporting the rigid bar anchorage system argued that adopting that system would further international harmonization of safety standards while adopting the flexible latchplate anchorage system would not. The GRSP of the United Nations Economic Commission for Europe stated that all of the governmental representatives expressing a view on the NPRM supported a move to two point rigid lower attachments. The GRSP stated that "...NHTSA should not encourage a unique national approach in its final proposals." Ms. Kathleen Weber, chairperson of the U.S. delegation to the ISO Working Group developing the draft ISO standard, stated:

It is clear that the European vehicle industry will move quickly to recessed rigid bars for its [lower vehicle anchorages for child restraints], U.S. manufacturers with world platforms will do the same, and such anchors will probably be required in non-US markets within a few years. By requiring the flat plate anchor in the U.S. market, NHTSA will penalize consumers with an extra cost burden and will isolate its child restraint market from the rest of the world.

Similarly, Transport Canada believed that the preferred system worldwide is the rigid bar anchorage system, and thus expressed a concern that the proposal's preference for the flexible latchplate system does not provide for worldwide harmonization.

Since the NPRM, ISO Working Group 1 (WG 1) finalized its working documents on the location of the rigid bar anchorages and the test procedure for evaluating them. In the June 1998 meeting in Windsor, Canada, the draft of the Canadian rule concerning requirements for top tether anchorages (see section d, below) was incorporated into WG 1 activities to serve as the basis for the preparation of an ISO document (ISO/WD13216-2) to be part of the ISO standard. The draft ISO standard will be circulated to the ISO member bodies for voting. To be adopted as an ISO standard, it has to be approved by at least 75 percent of the member bodies casting a vote. NHTSA understands that the full committee will vote on the draft international standard in early 1999.

In June 1998, the agency received letters from child restraint manufacturers Kolcraft, Cosco and Century expressing qualified support for the rigid bar anchorage system. These manufacturers had originally responded to the NPRM strongly opposed to that system but changed their minds apparently after realizing that the rigid bracket connector would not be required for the child restraint system.

These manufacturers stated that they now prefer the rigid bar anchorage system over the flexible latchplate system,⁽¹⁶⁾ provided that the access and location of the anchorages allows design flexibility for either a frame mounted (bracket-based) or a flexible (strap) mounted connector on the child restraint. Factors cited for the change in preference were performance, future child restraint system design flexibility and international harmonization. Century said, however, that the bars have to be accessible and visible. Cosco believed that the cost effectiveness of the rigid bar anchorage system and flexible latchplate system would be approximately equal, and that "any differences in the using public concerning ease of use and/or desirability of one with respect to the other would soon disappear if such a real difference exists at all today." Cosco stated that the rigid bar anchorage system

would help to eliminate certain types of force vectors which may occur within the system of flat latchplates that could be detrimental. It also clearly distinguishes the car seat attachment system from any other hardware that may be near by.

In April 1998, the American Automobile Manufacturers Association (AAMA) and the Association of International Automobile Manufacturers (AIAM) asked MORPACE International, Inc., to conduct a consumer clinic to determine which of several methods of attaching child restraints consumers in the U.S. find most acceptable. Century 1500 STE Prestige convertible restraints were used as the representative child restraint. The baseline method of attaching the Century seat was the vehicle belt system. This was compared against a flexible latchplate system (with the buckles attached to the child restraint by straps) and a rigid bar anchorage system (with hooks and other connectors attached to the child restraint by straps or by a rigid bracket attachment), and variations of these attachments. A Volkswagen Passat sedan was fitted with a flexible latchplate system and with the rigid bar anchorage system.

The clinic participants were 254 people who were the principal drivers of their vehicle and who care for children 4 years of age or less. Each participant was asked to install the child restraints and then asked about his or her interest in the restraint. Later, the participants were informed of the prices for the restraints and were asked again about their interest in each restraint. The prices MORPACE gave for the baseline child restraint was $63, the child restraint equipped with buckles for the flexible latchplate system was $78, the child restraint with the rigid bracket attachment for the rigid bar system was $128, the rigid bar anchorage strap-based restraint with a snap hook was $73, and the rigid bar anchorage strap-based system with a buckle-type connector to a 6 mm bar was $80.

The following is the percentage of the participants who were very/somewhat interested in the restraints before and after they were informed of the prices. UCRA (78/77 percent); rigid bar anchorage restraint with a buckle attached to it by webbing (67/57 percent); rigid bar anchorage restraint with rigid bracket-based attachment (64/45 percent); and rigid bar strap-based system with snap hook (64/45 percent). After the prices were provided, the UCRA restraint was most preferred (39 percent), followed by the rigid bar anchorage restraint with rigid bracket-based attachment (19 percent), the rigid bar strap-based system with snap hook (15 percent), and the rigid bar anchorage restraint with a buckle attached to it by webbing (14 percent). The study stated that the reason behind the bracket-based rigid bar anchorage option's being rated second instead of first is its higher price and weight. Restraints equipped with variations of these UCRA and rigid bar anchorage connectors also received support, as did the baseline restraint, albeit in smaller percentages. MORPACE prepared a final report on the clinic and its findings, which the agency placed in docket NHTSA-1998-3390.

Following the issuance of the report, a number of motor vehicle and child restraint manufacturers wrote to NHTSA concerning the findings. Copies of these letters have been placed in docket 3390. GM and Indiana Mills Manufacturing Inc. (IMMI) stated that they believed that the clinic showed that consumers' preferences are highly in favor of the flexible latchplate system. GM and IIMI stressed that the clinic showed that consumers are willing to pay the added cost of the flexible latchplate system for added security and performance, but that consumers will not accept the cost and weight of a bracket-based rigid bar anchorage child restraint.

Some manufacturers did not agree that the clinic necessarily showed a preference for the flexible latchplate system. BMW, Volvo, Volkswagen, Mercedes-Benz, Toyota, Fisher-Price and the University of Michigan Child Passenger Protection Research Program believed that the clinic showed that child restraint systems interfacing with the rigid bars had a combined first choice preference of 48 percent, compared to a 40 percent first choice preference for the flat latchplate. Chrysler did not believe it was appropriate to add the proportions of participants who expressed preferences for the rigid bar anchorage variants and to express that sum as a preference for the round bar anchorage. However, Chrysler believed that the clinic's findings are limited in that they reflect consumer views on the "ease of use" of a child restraint but not consumer preference for the vehicle anchorages used. Chrysler also reiterated its belief, expressed in earlier comments to the docket, that the rigid bar anchorage system has greater potential safety benefits than the flexible latchplate system.

Ford believed that while it may not be statistically valid to add the percentages of respondents favoring child restraints that attach to the rigid bar anchorages, it would be "directionally right, in that the [rigid bar anchorages] are more flexible [design-wise] and can be used with a wider variety of child restraints." Ford believed that the clinic found that consumers want (1) an alternative way of attaching child restraints, and (2) more than anything, a child restraint that provides safety and security. Ford reiterated its belief that the rigid bar anchorage system is the best vehicle system. Ford said the system provides consumers with a wider variety of child restraints, and is the most immobile, a feature that MORPACE has said signifies to consumers that the seat is secure, which MORPACE says was "the most important criterion" for the respondents in evaluating a child restraint.

Century Products stated that it believed that the high preference rating for child restraints designed for the flexible latchplate system is due to the familiarity of the latchplates. The company stated that "the three designs using the 6 mm rigid bars in the vehicle also showed acceptance by the respondents indicating that the 6 mm bar is acceptable to users."

A number of these commenters also said that the prototype child restraints used in the clinic were of highly inconsistent quality. For example, some believed that the rigid bar anchorage bracket-based restraint was not representative because it was unrealistically heavy, high, and upright, in order to adapt the unmodified production Century restraint to a rigid bar anchorage base. It was 3.6 kg (8 lb) heavier than the UCRA restraint. They stated that, in contrast, the flexible latchplate restraint and others did not include the weight of any of the reinforcements that are needed for the restraint to meet Standard 213's dynamic test and thus were lighter than would be an actual restraint. They also believed that the vehicle's flexible latchplates used in the clinic were substantially more sophisticated than what the agency had proposed and thus far more costly. Chrysler also said that the $128 price given for the rigid bar anchorage bracket-based child restraint was too high, because costs would be lowered if the bracket mechanism were produced in high volume.

In September 1998, Canada adopted its final rule amending its tether anchorage requirement in section 210.1 of the Canadian Motor Vehicle Safety Regulations. As a result of an effort to harmonize internationally on tether anchorage requirements, NHTSA's proposal on tether anchorages reflected almost all of the provisions that had been proposed by Canada (March 15, 1997) prior to its final rule.

Since 1989, Canada had required that tether anchorages be installed on all passenger cars. However, that requirement did not require tether anchorages to be "user-ready," i.e., it did not require the installation of the hardware necessary for the attachment of the tether strap. Consumers could not use the tether anchorage on the vehicle as delivered from the factory. While Canada required that manufacturers provide a pre-drilled hole in a reinforced location specifically designed for the installation of the hardware, it did not require that such hardware be installed. Consequently, parents typically had to take their vehicle to a dealer or repair shop to have the hardware installed. Canada's new rule requires the factory installation of user-ready tether anchorages for all anchorages in passenger cars manufactured on or after September 1, 1999, and a year later in all minivans and light trucks.

The Canadian rule requires a specified number of tether anchorages, depending on vehicle type and the number of rows or seating positions in the vehicle. Generally, it requires passenger cars and minivans to have two or three anchorages. The rule specifies the zone in which a tether anchorages must be located for a particular seating position. It specifies strength requirements, and a method for testing the strength of the anchorages.

The rule contains a number of changes to the test procedure that Canada had proposed for testing the strength of the anchorages. The proposal would have specified testing the anchorages by attaching a strap to the anchorage and passing that strap forward over the seat back. In response to comments and discussions with manufacturers, Canada changed the test method to specify the use of one of two prescribed static force application test devices. Both represent a child restraint system with a tether. One device replicates a child restraint that attaches to a rigid bar anchorage system. This device will be used to test the tether anchorage in a seating position that has the rigid bar anchorage system. The other represents a child restraint that is attached by the vehicle's belt system, and is used to test a tether anchorage at a position that is not equipped with a rigid bar anchorage system. The test is conducted by installing the test device on the seat using the seat belt or the rigid bars, as appropriate, attaching the tether strap to the tether anchorage, and applying a test force to the child restraint device, rather than directly to the tether anchorage.

VI. Agency Decision Regarding Final Rule

This final rule requires motor vehicle manufacturers to install child restraint anchorage systems, consisting of lower rigid bar anchorages and a user-ready upper tether anchorage, in their vehicles. The 6 mm round bars in the vehicle seat must be rigidly mounted. Thus, they may not be attached to the vehicle by webbing material. This rule also requires child restraints to be permanently equipped with a means of being attached to the lower vehicle anchorages. It does not, however, specify either the design of the means of attachment or how that means is permanently attached to the child restraint.

This rule requires vehicles to have two child restraint anchorage systems at two rear designated seating positions, if the vehicle has at least two rear seating positions. This rule also requires vehicles with three or more rear designated seating positions to have a user-ready upper tether anchorage at a third rear seating position.⁽¹⁷⁾ It amends the child restraint standard by reducing the limits on allowable head excursion. The agency expects that in order to comply with the reduced limits, most forward-facing child restraint models will be equipped with an upper tether strap. When used, a tether reduces head excursion and the likelihood of head impacts against the vehicle structure.

To provide consumers with the rigid bar anchorage system as quickly as possible, this rule will start a three-year phase-in of the requirements for the rigid bars, beginning September 1, 2000. The bars will ultimately be required in all passenger cars, and in trucks and multipurpose passenger vehicles with a gross vehicle weight rating (GVWR) of 3,856 kg (8,500 lb) or less, and in buses (including school buses) with a GVWR of 4,536 kg (10,000 lb) or less. There will be a two-year phase-in of the user-ready tether anchorage for passenger cars beginning September 1, 1999. The user-ready tether anchorage will be required in the other vehicle types⁽¹⁹⁾ beginning September 1, 2000.

Child restraints will be required to have the components for attaching to the rigid bars beginning September 1, 2002. The restraints will be dynamically tested under Standard 213 when attached by those components to rigid bars on the standard seat assembly specified in the standard. They will be tested both with and without attaching a tether. Child restraints will have to meet a reduced head excursion limit beginning September 1, 1999. A tether will probably be needed to meet this requirement, and one may be attached for the test. Child restraints will also have to meet the standard's existing head excursion limit when tested attached by a lap belt and nothing else, to ensure that head excursion is limited if the tether is not used.

The estimated average cost of this rule is approximately $152 million annually. The cost of the rule for vehicles is estimated to be about $85 million. The costs of the rule related to the vehicle will range, per vehicle, from $2.82 (one rigid bar anchorage system in front seat only) to $6.62 (for a system in front seat and one in back seat or two systems in rear seats, plus a tether anchorage). NHTSA estimates that 15 million vehicles will be affected annually: 9 million passenger cars and light trucks with "adequate" rear seats, 3 million vehicles with no rear seat, and 3 million vehicles that can only accommodate a forward-facing child restraints in the rear seat (not a rear-facing infant seat). The impact of the rule on child restraint systems is estimated at $67 million (3.9 million child restraints at $17.19 per restraint, based on webbing-attached connectors). The cost per child restraint system varies depending on the type of connector used, e.g., a hook versus a buckle, and the means used to attach the connector to the child restraint system, e.g., webbing versus a rigid attachment.

The annual benefits of the rule are estimated to be 36 to 50 lives saved, and 1,231 to 2,929 injuries prevented.

The main difference between the final rule and the NPRM concerns the lower anchorage portion of the child restraint anchorage system in vehicles. Instead of permitting a choice between lower anchorages of either the flexible latchplate system or the rigid bar system, the final rule mandates the latter system. The NPRM would have allowed vehicle manufacturers the option of installing the rigid bar system only if they provided an adapter, such as a connector (that need not have been permanently attached to the vehicle) that would have had a component on one end that latches onto the rigid bar, and a latchplate on the other, for attaching to buckles on a child restraint that is designed for a flexible latchplate anchorage system. Commenters overwhelmingly opposed an adapter, believing that the adapter would be lost or misused by consumers. On reevaluating this issue, NHTSA agrees that mandating a single system would better ensure that the child restraint anchorage system is universal to all vehicles, for all child restraints, and for all consumers regardless of the type of vehicle or child restraint they may be using for a particular trip.

Second, this final rule requires vehicle manufacturers to rigidly-mount the 6 mm bars. Thus, it does not permit the bars to be attached to the vehicle by webbing, as had been proposed. The purpose of requiring rigid mounting is to maintain better control over the compatibility between child restraints and the anchorage system. However, connectors on the child restraint are permitted either to be attached by webbing, or to be rigidly mounted.

Other differences between this final rule and the NPRM relate to provisions concerning: the types of vehicles and of child restraints that are subject to the requirements; the number of anchorage systems that are required in each vehicle; the visibility and placement of the rigid bars in the vehicle; a requirement for an audible or visual indicator that the child restraint is securely attached to the bars; the strength requirements and test procedures for testing the child restraint anchorage system and the tether anchorage; and leadtime for and a phase-in of the requirements.

VII. Issue-by-Issue Discussion of the Agency Decision on Content of Final Rule

The agency initially gave preference to the flexible latchplate anchorage system over the rigid bar anchorage system after weighing the abilities of each system to accomplish the goals that the agency believed a uniform attachment system should meet. 62 FR at 7867-7868. NHTSA believed that an anchorage system should:

• Improve the compatibility between child restraint systems and vehicle seats and belt systems, thereby decreasing the potential that a child restraint was improperly installed;
• Ensure an adequate level of protection during crashes;
• Ensure correct child restraint system use by ensuring that the child restraint systems are convenient to install and use, and will be accepted by consumers;
• Ensure that the child restraint systems and anchorages are cost effective and available within a reasonable leadtime; and,
• Achieve international compatibility of child restraint performance requirements for uniform anchorage points.

NHTSA tentatively concluded that the flexible latchplate system would, on balance, best achieve these goals. The agency stated that the rigid bar anchorage system and flexible latchplate anchorage system appeared comparable in terms of safety performance and public acceptance, but the flexible latchplate anchorage system appeared to have advantages over the others with respect to its cost impact, and near-term availability. The agency further stated that the flexible latchplate anchorage system had advantages in terms of its usability and visibility. The agency believed the familiarity of the components (particularly the crucial connector pieces--buckles and latchplates--that attach a child restraint to the vehicle system) was a definite advantage over the other systems. Also, the agency believed that child restraints designed for use with the flexible latchplate system were not as bulky or heavy as child restraints designed for use with the rigid bar anchorage system, which would increase the public acceptance of the flexible latchplate system.

The agency's proposal to give preference for the flexible latchplate system over the rigid bar anchorage system for the lower anchorages was supported by some commenters, but opposed by most commenters in their comments on the NPRM or in their post-comment period submissions. Proponents of the flexible latchplate anchorage system agreed with the agency's tentative conclusions in the NPRM that the system appeared to be superior to the rigid bar system because a child restraint made for the flexible latchplate anchorage system would be less costly, bulky and heavy than a child restraint designed to attach to a rigid bar anchorage system. Some commenters supported the flexible latchplate anchorage system because they believed that a rule based on that system could be implemented more quickly. Some believed that the flexible latchplate system was preferable because its buckle is simple, intuitive, and familiar to consumers. GM argued that the AAMA/AIAM 1998 consumer clinic proved that consumers overwhelmingly prefer the flexible latchplate anchorage system because of its superior installation accuracy and acceptable costs, compared to alternative concepts, including the rigid bar anchorage system.

Opponents of the flexible latchplate anchorage system disagreed with those views. They believed the rigid bar anchorage system and the flexible latchplate anchorage system would have similar cost, weight and leadtime impacts. They stated that the agency's tentative decision to give preference to the flexible latchplate anchorage system was based on faulty premises, such as believing that the hardware interfacing with the rigid bars would necessarily be costly and unavailable in the near-term. These parties strongly disputed that the 1998 consumer clinic showed the flexible latchplate anchorage system had greater public acceptance. In fact, many believed the clinic showed a public preference for systems using the rigid bar anchorage system in the vehicle, because most of the respondents chose, as their first choice, variations of child restraints that had attachments that were designed to attach to the rigid bar anchorage system. (Forty-eight percent chose child restraints designed to attach to the rigid bars, compared to 39 percent that chose child restraints designed for the flexible latchplate system.)

After reviewing the comments and other new information before it, NHTSA concluded it needed to revise its assessment of the relative merits of the flexible latchplate system and the rigid bar anchorage system. The agency's main reason for proposing to give preference to the flexible latchplate system over the rigid bar anchorage system was information indicating that the installation of rigid bar anchorage systems in motor vehicles would make it necessary for child restraints to be equipped with the following three features: two rigid prongs, or brackets; a heavy supporting structure for those prongs or brackets; and specialized jaw-like clamps to attach to the rigid lower anchorages on the vehicle. This information consisted of statements by the supporters of the rigid bar anchorage system describing the child restraints and of the prototypes or mock-ups they had provided prior to the NPRM. Those prototypes or mock-ups included all three of these features. The addition of these features to child restraints would have had a substantial cost impact on child restraints (essentially doubling the price of a child restraint), and added substantially to its bulk and weight. The agency also believed that manufacturers would need substantial time to design child restraints with the brackets and supporting structure. Further, NHTSA was concerned that consumers would not be familiar with the new technology.

All commenters supporting the rigid bar anchorage system told the agency that the brackets were not necessary to attach a child restraint to the rigid bar anchorage system. Commenters, including many child restraint manufacturers, said that a simple hook, made to attach to a rigid bar, could and would be used by many child restraint manufacturers if the rigid bar anchorage system were adopted. The hook could be attached to the child restraint by means of webbing, identical to the attaching of the buckle on a child restraint designed for the flexible latchplate system. After the NPRM was published, some child restraint manufacturers developed prototype child restraints, equipped with hooks, to demonstrate to NHTSA the feasibility of using hooks as the connector hardware and of using webbing for attaching hooks to a child restraint. Further, almost all of the child restraint manufacturers asserted that, if allowed, they would use straps to attach the connector to the child restraint. These assertions apparently reflected their judgment that the use of straps would be practicable and publicly acceptable.

These new prototypes, reinforced by the new assertions of the child restraint manufacturers, changed NHTSA's assessment of the relative advantages of the flexible latchplate and rigid bar anchorage systems. The emergence of straps as a viable means of attaching the connector made it necessary for the agency to reverse its earlier tentative conclusion that a child restraint must have the heavy brackets to attach to a rigid bar anchorage system, and its derivative tentative conclusions about related advantages of the flexible latchplate system concerning the cost, bulk, and weight of child restraints designed for the system.

NHTSA's cost estimates in the NPRM were based on the information indicating that the brackets had to be used on the child restraint system. The high cost of a rigid bar anchorage child restraint, relative to a flexible latchplate child restraint, was mostly due to the material then believed by the agency to be needed for the bracket structure and not to the cost of the hardware connecting to the 6 mm bar. Several commenters stated that buckles designed to attach to 6 mm bars would, as production volume rose, ultimately be comparable to, if not less than, the cost of the buckle of the flexible latchplate system. NHTSA agrees with these statements because the types of components (spring, latch, release button and casing) of current prototype buckles designed to attach to a rigid bar and to the flexible latchplate, are basically the same. Because the same types of components are used in both buckles, it is reasonable to conclude that the cost under similar production assumptions are likely to be similar. Thus, there would be no significant cost difference between a child restraint designed for the rigid bar anchorage system that uses webbing to attach the connector to the restraint and a child restraint designed for the flexible latchplate system. Accordingly, the agency now concludes there need not be a cost advantage to the flexible latchplate system compared to the rigid bar anchorage system.

NHTSA also believes that child restraints designed for the rigid bar anchorage system would be comparable in weight and bulk to child restraints designed for the flexible latchplate anchorage system if they used webbing to attach the connector to the child restraint. The incremental bulk and weight of a rigid bar anchorage child restraint, relative to a flexible latchplate child restraint, was due to the material then believed by the agency to be needed for the bracket structure and not to the hardware connecting to the rigid bar. Accordingly, there need not be an advantage to the flexible latchplate anchorage system over the rigid bar anchorage system in terms of the bulk and weight of the child restraints.

Supporters of the flexible latchplate anchorage system argue that the AAMA/AIAM consumer clinic shows that consumers prefer their system and that for this reason, the flexible latchplate system should prevail. NHTSA's view of the clinic results is discussed in Appendix B. In brief, the agency cannot conclude that the results clearly warrant the agency's selection of either the flexible latchplate system or a rigid bar anchorage system. The agency recognizes that consumers gave their highest scores to the flexible latchplate design used in the clinic. However, combining the results of the child restraints designed for the rigid bar anchorage system accounted for an even larger number of participants. Further, NHTSA believes that the high score of the flexible latchplate design was at least partially due to the fact that consumers are currently more familiar--and perhaps more comfortable--with the buckle and latchplate design. The agency believes further that once the rigid bar anchorage system and child restraints with the new connectors are introduced, the public will become equally familiar and comfortable with those new designs. Moreover, the agency anticipates that consumers will be receptive to the design flexibility of the rigid bar anchorage system. As discussed below in section d.2., the anchorage system allows them to choose from a variety of connector hardware designs and child restraint systems to satisfy their needs.

The NPRM would have allowed vehicle manufacturers the option of installing the rigid bar anchorage system if they provided an adapter (that need not be integral to the vehicle) that would enable a child restraint that is designed for the flexible latchplate system to be used with the rigid bars. The adapter would have to latch at one end onto the rigid bar and at the other end onto the flexible latchplate system buckle. Commenters overwhelmingly opposed the concept of an adapter, believing that adapters would be lost or misused by consumers. For example, Toyota Motor Corporation stated that an adapter-

will further complicate the tightening procedure and therefore securing the CRS will be more difficult. Accordingly, we believe that there will be an increased possibility of misuse, resulting in loose fit and/or improper securing of the CRS to the vehicle. In addition, we believe this will add to the owner's confusion as to how to properly affix this system. * * * In addition, Toyota is concerned as to whether the owner of these vehicles will take the necessary precautions to keep from losing the adapter(s), as any additional loose articles in a vehicle are more likely to be misplaced or lost.

After reviewing the comments, the agency concludes that mandating a single type of anchorage system would ensure that motorists will find the same child restraint anchorage system in all vehicles and that the system will be compatible with all child restraints, regardless of the make or model of vehicle or child restraint they may be using for a particular trip. Allowing use of an adapter might not only perpetuate existing child restraint compatibility problems, but also exacerbate them beyond what they are today. Thus, the agency decided it must choose one, and only one, system to require.⁽²⁰⁾

NHTSA's selection of the rigid bar anchorage system advances its international harmonization policy goal of identifying and adopting those non-US safety requirements that reflect equivalent or higher levels of safety performance than the counterpart U.S. standard. Requiring the rigid bar system will enhance the safety of child restraints by making them easier to install and possibly more securely installed than by means of the vehicle's belt system. Further, harmonizing the U.S. standard permits vehicle and child restraint manufacturers to have a greater measure of planning certainty and predictability in designing and selling their products, helps ensure that parents are provided an anchorage system that meets their safety needs at the lowest possible cost, and facilitates the global marketing of child restraints.

NHTSA's selection of the rigid bar anchorage system also accords with its statutory obligations. The Trade Agreements Act of 1979, as amended (July 26, 1979, P. L. 96-39, §1(a), 93 Stat. 144.) (19 U.S.C. §2501 et seq.), requires Federal agencies to take into consideration international standards and, if appropriate, base the agencies' standards on international standards. In addition, the National Technology Transfer and Advancement Act of 1995 (Public Law 104-113) requires all Federal agencies to use technical standards "that are developed or adopted by voluntary consensus standards bodies, using such technical standards as a means to carry out policy objectives or activities determined by the agencies and departments."

The rigid bar anchorage system is the one most likely to be chosen as a harmonized design under the auspices of the United Nations Economic Commission for Europe (UN/ECE).⁽²¹⁾ The rigid bar anchorage system is supported by the expert group within WP.29 that considers issues relating to child restraints and vehicles, the Group of Rapporteurs for Passive Safety (GRSP). At the 23^rd session of the GRSP meeting of experts in June 1998, the GRSP accepted a proposal for requiring rigid bar anchorages. At the 24th session of the GRSP meeting of experts in December 1998, the GRSP formed an informal group to look into developing a proposal to be presented at the May 1999 GRSP meeting. The proposal is to consist of alternative means, including a top tether, to reduce the possibility of undesirable rotation that might otherwise occur when a child restraint is attached to some vehicle seats by means of the two lower rigid bar anchorages only. The GRSP plans to discuss the proposal during the May 1999 meeting and expects to decide during its December 1999 meeting whether to adopt a means to address the concern of possible undesirable rotation and, if so, which means should be adopted.

The rigid bar anchorage system is also favored in other international forums as well. The rigid bar anchorage system, with a top tether anchorage, is the system preferred by Canada and Australia and is the child restraint anchorage system most likely to be adopted by those countries. Both of these countries already require a user-ready tether anchorage for attaching child restraints.

The International Standards Organization (ISO) also appears to be moving toward adoption of the rigid bar system. The ISO working group that has been developing the rigid bar anchorage system is completing its working documents on the system and is preparing to circulate the draft standard to the ISO member bodies for voting. The ISO working group circulated a committee draft report for voting. The ballots received by the deadline of May 4, 1998 showed that no country disagreed to circulate a draft of the international standard to the ISO Central Secretariat for ballot. (The U.S. abstained from voting because agreement has not been reached within the U.S. domestic auto industry on the use of rigid versus flexible anchorages.) NHTSA understands that the full committee will vote on the draft international standard in the near future. To be adopted as an ISO standard, the draft has to be approved by at least 75 percent of the member bodies casing a vote.

The rigid bar anchorage system encourages design flexibility to a greater extent than the flexible latchplate anchorage system. The rigid bar anchorage system has the advantage of allowing child restraint manufacturers flexibility in developing a variety of possible connectors to the bars. Unlike the flexible latchplate system, which envisions a specific design of a buckle to connect to the latchplate, the rigid bar anchorage system gives child restraint manufacturers maximum leeway in designing connectors.⁽²²⁾

For example, child restraint manufacturers may use designs ranging from jaw-like clamps to buckles to simple hooks, and may attach these to the child restraint using means ranging from brackets to webbing. A number of child restraint manufacturers support the rigid bar system because of its design flexibility.

The design flexibility of the rigid bar system also has implications for potential improvements in the safety provided by child restraints. For example, Century Products has indicated that the rigid bar system could enable them to design booster seats (a type of child restraint system, see 49 CFR §571.213, S4) for children over 18 kg (40 lb) that could better limit head excursion than present boosters. A rigid attachment on the booster restraint might reduce some of the excessive forward motion that a child restraint attached to the vehicle seat by a belt experiences when tested with a 6-year-old dummy, due to elongation of the belts.

Consumers would also benefit from design flexibility, in that they could choose from a variety of child restraint systems to purchase to suit their needs or tastes. For some, a one-step "plug-in" design, such as that seen on Britax prototypes with rigid connectors, might be the most convenient or desirable, while others may prefer a child restraint that has a connector attached by webbing because such a system would weigh and cost less than restraints that have rigid connectors.

The NPRM stated that both the flexible latchplate anchorage system and the rigid bar anchorage system have performed satisfactorily in dynamic tests, which implied that both would provide comparable levels of safety. Supporters of the rigid bar anchorage system disagreed with the agency, suggesting that that system has the potential to better protect children with regard to two aspects of safety.

The first safety aspect concerns the relative performance of the systems in side impacts. Michael Griffiths and Paul Kelly of the Roads and Traffic Authority (RTA), New South Wales, Australia, submitted data on side impact sled tests RTA conducted comparing the performance of the CAUSFIX system (CAUSFIX is the rigid bar anchorage system with a tether anchorage, which is the system NHTSA is adopting in this final rule, see footnote 13, supra), the flexible latchplate system, and a lap belt plus tether system. ("Comparative Side Impact Testing of Child Restraint Anchorage Systems," Kelly, Roads and Traffic Authority, New South Wales, Special Report 96/100, March 1997.) The side impact tests were conducted in accordance with Australian Standard (AS) 3691.1, except for the addition of a simulated door structure, replicating a rear door of a large sedan, adjacent to the test seat. Testing was conducted with the test seat mounted at both 90 degrees and 45 degrees to the direction of sled travel. The lower anchorage points for the CAUSFIX were positioned 280 mm (11 inches) apart on the test seat structure, with the inboard anchorage approximately 610 mm (24 inches) from the inner surface of the door. An instrumented 9-month-old dummy was used in all the tests.

RTA found that, for forward-facing seats,⁽²³⁾ only the CAUSFIX was able to prevent contact between either the dummy's head or the child restraint and the door structure in the 90 degree test. RTA stated that head contact with the door was evident in the test involving the flexible latchplate system.

This appeared to be largely the result of the restraint rotating towards the door at the end of its sideways movement. As a consequence, the dummy's head moved forward relative to the CRS [child restraint system] and contacted the front portion of the side-wing. In turn, the side-wing deflected and allowed the head to roll around its front edge, as the CRS rebounded from the door. . . . In contrast, the CAUSFIX system did not allow rotation. . . . The CAUSFIX concept offered better head protection compared to the conventional seat belt/top tether systems.

(Id., page 5.)

Many of the supporters of the rigid bar anchorage system included comments on their belief that side impact benefits could be attained with the system. In contrast, GM stated in its comment (pp. 10-11):

It has been alleged that the proposed combination of UCRA anchorages and a strap-based CRS may not provide adequate protection in a high severity lateral impact. However, no field accident statistics have been provided to support an allegation that high speed lateral impact performance should be a primary area of concern in the U.S. In fact, data analyzed by NHTSA researchers demonstrate that the primary child safety issue is the non-use of CRSs. A secondary concern is misuse of the CRS. Misuse includes failing to properly fasten the CRS's internal harness system or improperly securing the CRS in the vehicle.

While various groups continue to develop proposals for lateral impact test protocols and related dummy and injury assessment techniques, it appears unlikely that consensus on these topics will be reached for years. The continued debate should not delay implementation of improved CRSs and UCRA systems. This is particularly true since it is not apparent that the current U.S. field situation demonstrates a need for a side impact crash evaluation protocol. Further, it has not been established that lateral dummy head excursion is a meaningful predictor of injury in side impacts. Even if it were, NHTSA tests have shown that the existence of a top tether reduces lateral head excursion by one third compared to a current CRS secured without a top tether....

NHTSA has evaluated these and all other comments on this issue and concludes that the agency cannot make a precise determination of the relative side impact benefits based on the information available thus far. The RTA's test data were few in number. Further, the real world relevance of the 90 degree test is unclear at this point. NHTSA does not know if the path of a child's head in a 90 degree impact will necessarily be lateral. The path will depend on a variety of factors, including the speed of the struck vehicle, and the point of impact to the struck vehicle (forward part, middle, rear part). Further, NHTSA cannot determine at this time whether reduced head excursions would necessarily reduce injuries and fatalities in side impacts. Crash data should be analyzed to determine answers to these issues. The agency has been working with the ISO working group on the development of a side impact test procedure. NHTSA will be taking part in an evaluation of the side impact test protocols in the future. For now, however, the agency cannot conclude that the rigid bar anchorage system is more advantageous than the flexible latchplate system in side impacts.

The second aspect of safety on which proponents of the rigid bar anchorage system commented was that the combination of rigid lower anchorages on both vehicles and child restraints would virtually guarantee that the child restraint would be snugly attached to the vehicle seat. Commenters stated that studies and informal clinics have shown that consumers regularly fail to properly tighten the belt used to install child restraints. With a rigid bar anchorage system on both the vehicle and the child restraint, the child restraint is secured automatically once the consumer properly attaches the two rigid points of the seat, so there is no need for a separate tightening action by the consumer. Conversely, GM stated that concerns about parents not tensioning the flexible latchplate belts are unfounded, based on the findings of GM's consumer preference clinic (GM did not elaborate on those findings).

A number of consumer advocates urged NHTSA to adopt the rigid bar anchorage system because they have witnessed that parents often do not adequately tighten the vehicle belt attaching the child restraint to the vehicle. A child restraint with rigid attachments designed to attach to rigid bar anchorages in the vehicle would eradicate the problem of excessive slack in the belts.⁽²⁴⁾ By adopting the rigid bar anchorage system, this final rule provides consumers the rigid bar anchorage system in the vehicle and provides them the opportunity to purchase a child restraint with the rigid attachments if they want the more convenient system.

This final rule adopts most of the requirements under consideration by the ISO, adopts some that are not part of the ISO draft standard, and adopts some requirements that are dissimilar to those under consideration by the ISO. These are discussed below. Other differences with the draft ISO standard are discussed throughout this section (VII).

The NPRM proposed to permit vehicle manufacturers to install "semi-rigid" anchorages in vehicles for the child restraint anchorage system. Semi-rigid bar anchorages refers to 6 mm bars that are attached by non-rigid material (webbing), extending from the vehicle seat bight. Semi-rigid bar anchorages basically look like the anchorages of the flexible latchplate system, except with a 6 mm round bar attached to the end of the webbing instead of a latchplate. The term "semi-rigid anchorages" is from the draft ISO standard (ISO/22/12/WG1, June 1998, Annex A), which permits vehicle manufacturers the option of installing semi-rigid bar anchorages as an interim alternative to the anchorages that are rigidly held in place. The draft ISO standard permits the use of semi-rigid bar anchorages for a limited period of time as an interim measure to address the concerns that had been expressed by some U.S. vehicle and child restraint manufacturers toward rigid bar anchorages. NHTSA's proposal allowed semi-rigid anchorages to harmonize to the extent possible with the version of the prospective ISO standard.

After reevaluating this issue, NHTSA has decided to require vehicle manufacturers to rigidly mount the 6 mm bars. Thus, bars may not be attached to the vehicle by webbing, as had been proposed. The agency made this decision to maintain better control over the compatibility between child restraints and the anchorage system. Requiring one type of attachment system on the vehicle (i.e., requiring the 6 mm bars to be rigidly mounted) better standardizes the vehicle anchorage system, which reduces the potential for confusion on the part of parents (who might be confused if they are looking for or expecting one type of anchorage system and come across another), and the misuse that typically results from confusion.⁽²⁵⁾ To determine whether a bar is "rigidly" mounted to the vehicle, this final rule specifies that the bar must be attached to the vehicle such that it will not deform (e.g., elongate, move, or deflect) when subjected to a 100 Newton (N) force in any direction. To further standardize the system, this final rule limits the length of the bars to not less than 25 mm, but not more than 40 mm. The upper limit is to reduce the likelihood that the bars may bend in a crash.

Even if NHTSA had decided to give vehicle manufacturers the option of installing non-rigidly mounted bars, it appears that they would not take advantage of that opportunity. Vehicle manufacturers supporting the rigid bar anchorage system did not indicate in their comments or other submissions that they would install non-rigid bar anchorages. NHTSA believes most, if not all, want to install the rigid bar anchorages. They emphasized what they believe to be superior side impact performance attributed to the rigid bar anchorage system, which can only be attained by use of a rigid system. They liked the fact that the rigid bar anchorage system did not give the appearance of "clutter" on vehicle seats from sets of child restraint anchorage belts and latchplates. Further, it appears that the provision for semi-rigid anchorages was included in the ISO draft standard to address what the working group believed was a desire to use such anchorages in this country. The Group of Experts on Passive Safety of the ECE stated in commenting on the NPRM that "[t]here is no benefit in Europe opting for a semi-rigid system as an interim step." NHTSA understands this to mean that European manufacturers are not interested in installing semi-rigid anchorages as an interim step prior to the installation of rigid anchorages.

While NHTSA has departed from its proposal in order to harmonize with revised location and visibility/marking requirements for rigidly-mounted anchorage bars in the draft ISO standard, the agency has not followed that draft standard in all respects. In the NPRM, the agency proposed location requirements for rigidly-mounted 6 mm bar anchorages. The location requirements were based on requirements developed in draft by the ISO working group in ISO/WD13216-1i, November 15, 1996. The NPRM proposed that the 6 mm diameter bars would be located using a child restraint fixture whose configuration and dimensions replicate a child restraint system. (The NPRM referred to the fixture as the "child restraint apparatus." For convenience, and in response to VW's suggestion in its comment, this final rule uses the term "child restraint fixture" (CRF), which is the term used in the draft ISO standard.) The CRF would be placed on the vehicle seat cushion and against the seat back. Anchorage bars that are rigidly attached were proposed to be located 50 mm (about 2 inches) behind of the rearmost lower corner surface of the fixture (called point Z). They also must not be more than 120 mm from the H point of the seating position. (The H point is the mechanically hinged hip point of a manikin which simulates the actual pivot center of the human torso and thigh. See definition, 49 CFR §571.3.)

In its June 1997 draft revision of the ISO standard, WG1 changed the rearward location requirement to specify that rigidly mounted bars shall be not more than 70 mm (2.7 in) behind point Z. (The limit on the forward placement of the bars was not changed.) This specification is reflected in the June 1998 draft standard. The distance for the fore-aft placement of the bars was increased from 50 mm to 70 mm (2 to 2.7 in) to make allowances for extremely contoured rear seats in some types of sport cars. Contoured seat cushions or seat backs in these vehicles may make it difficult to place the bars within 50 mm (2 in) of the CRF without having the bars be so far forward in the seat bight that they interfere with the comfort or safety of adult occupants.

Some commenters (Century, Gerry Baby Products, IMMI, Evenflo, and Cosco) were concerned about the visibility and accessibility of the bars at the seat bight. Other commenters pointed out that the ISO working group would be revising its draft standard and suggested that NHTSA should reference the location requirements of the revised draft standard.

After evaluating the comments, NHTSA has decided to adopt the limits on the forward (not more than 120 mm from the H-point of the seating position) and rearward (not more than 70 mm behind point Z) placement of the bars in the current draft ISO standard. The agency has determined that the 70 mm distance is needed to ensure that the bars are rearward enough in vehicles with contoured cushions to limit excessive head excursions for children in a crash⁽²⁶⁾ and to avoid injuring the person occupying the vehicle seat in a crash or interfering with his or her comfort during normal vehicle operation. At the same time, the agency is mindful of the concerns of child restraint manufacturers that the child restraint anchorage system must be visible and accessible to be properly used.

NHTSA believes that most vehicles, except those with highly contoured seats, will have the bars 50 to 60 mm (2 to 2.4 in) from the CRF. At this distance, the agency believes that the bars would generally be visible at the seat bight without compressing the seat cushion or seat back.

The final rule requires that vehicles in which the bars are not visible must have a permanent mark on the vehicle seat back at each bar's location. The permanent mark required by this final rule is a small 13 mm (½ inch) diameter circle in a color that contrasts with the seat material and that is located above each individual anchorage, to help users locate and use the bars. The mark will indicate the presence of the anchorage system and act as a guide showing where to engage the bars. Consumers may not otherwise learn of the existence of a child restraint anchorage system in a particular vehicle or at a particular seating position in a vehicle without some type of visual reminder that the anchorage system is present. Even when they know the bars are present, they may not know precisely where in the seat bight to look for the bars. NHTSA notes if vehicle manufacturers do not want to mark their seats for esthetic or cost reasons, they need not do so if they install the bars such that there is an unobstructed view of the bars at an angle of 30 degrees from a horizontal plane tangent to the seat cushion.

This visibility requirement is significantly different from the one that NHTSA proposed and somewhat different from the visibility requirement in the draft ISO standard. In the NPRM, NHTSA proposed that, for rigid bar anchorages, inter alia, at least one lower anchorage bar shall be readily visible to the person installing a child restraint. That proposal was based on the ISO draft version in existence at the time. The ISO working group changed those requirements in the June 1997 draft version to specify that, wherever possible, at least one lower anchorage bar, one guidance fixture, or one seat marking feature (significantly larger than the one specified in NHTSA's final rule) shall be readily visible to the person installing the child restraint. NHTSA has determined that the proposed visibility requirement for the bars would have likely precluded vehicle manufacturers from placing the bars at the maximum 70 mm distance from the CRF, since at that distance the bars may not be visible. As stated above, the bars may need to be placed at the maximum distance on extremely contoured seats for the safety and comfort of adult passengers seated in that seating position. Because of this, the agency is not adopting its proposal that at least one of the bars has to be visible.

The NPRM requested comments on whether the webbing attaching the anchorage hardware on the child restraint should be color coded to distinguish the webbing from the straps comprising the harness for the child. A number of commenters supported color coding, while others did not. The agency has decided not to require color coding of the attachment system at this time. The Insurance Corporation of British Columbia (ICBC) and IMMI report contrasting experiences with regard to the propensity of clinic participants to confuse the webbing attaching the buckles of the flexible latchplate system to the child restraint with the webbing of the child restraint's internal harness. NHTSA notes that intermixing appears to be far less likely with the rigid bar system than with the flexible latchplate system because the types of connectors used to attach to the rigid bars are not likely to look like the buckles used for the child restraint harnesses.

The NPRM proposed to require user-ready top tether anchorages in vehicles. The draft ISO standard does not at this time include a provision for tether anchorages. Some supporters of a rigid system on both vehicles and child restraints believe that some restraints made to attach to the vehicle by means of a rigid attachment can meet a more stringent head excursion limit without a tether.

Test data show that an attached tether substantially improves the ability of a child restraint to protect against head impacts in a crash, when the child restraint is attached to the vehicle seat by the belt system or by a flexible latchplate anchorage system. In the U.S., parents have not attached the tethers in vehicles that lack a user-ready tether anchorage. However, Canada's experience indicates that parents are more likely to attach the tethers when a user-ready tether anchorage is factory-installed. Overall, commenters to the NPRM agreed with the agency that consumer-ready tether anchorages in vehicles are needed to increase the likelihood that consumers will attach a tether. For these reasons, and because a large proportion of child restraints will likely be attached to the child restraint anchorage system by webbing material, NHTSA believes there is good reason to require a user-ready tether anchorage in vehicles. The agency notes that the requirement for a user-ready tether anchorage will harmonize with Canadian requirements adopted in September 1998.

The NPRM proposed to apply the requirement for a child restraint anchorage system to passenger cars, and to trucks, multipurpose passenger vehicles and buses under 4,536 kg (10,000 lb) gross vehicle weight rating (GVWR). The agency had tentatively decided to include vehicles with a GVWR between 3,856 and 4,536 kg (8,500 and 10,000 lb) in an effort to ensure that such a child restraint anchorage system would be available in vehicles used to transport children to child care programs.

Commenters on the proposed applicability of the rule discussed whether there was a need to apply the rule to all vehicles