Report to Congress
STATUS OF NHTSA PLAN FOR
SIDE IMPACT REGULATION HARMONIZATION AND UPGRADE
March 1999
Executive Summary
On September 16, 1996, the U.S. Congress directed the National Highway Traffic Safety Administration (NHTSA) to study the differences between the U.S. and proposed European side impact regulations and to develop a plan for achieving harmonization of these regulations. In response to this directive, NHTSA submitted a side impact harmonization plan to the U.S. Congress in April of 1997 [1]. In the Senate Appropriations Committee, Report 105-249, September 1998, Congress further directed NHTSA to provide a report to the House and Senate Committees on Appropriations by December 15, 1998, on progress in addressing side impact harmonization issues. The specific language in Report 105-249 is:
Side impact standard harmonization. - In the conference report accompanying the fiscal year 1997 bill, the conferees noted that there are substantial differences between the U.S. side impact standard and a similar European requirement. The report notes that "these differences are inconsistent with the need for the international harmonization of motor vehicle safety standards", and directed that a report be provided on NHTSA's plan for achieving harmonization of the side impact rule. The Committee is concerned that NHTSA is not moving forward more aggressively on this matter, particularly since a harmonized standard could result in a safety improvement for U.S. motorists. Therefore, the committee directs NHTSA to use funds made available in the vehicle safety performance standard program budget for development of a harmonized side impact standard so long as the Administrator is convinced that such a harmonization effort will improve the safety of U.S. motorists. The Committee directs NHTSA to report to the House and Senate Committees on Appropriations by December 15, 1998, on progress in addressing this issue.
This report responds to this directive and provides Congress with detailed information on the progress that the agency has made in determining the possible functional equivalence between the U.S. and European side impact requirements and on the eventual global harmonization of side impact standards.
The first phase of the agency's 1997 plan involved crash testing vehicles compliant with the U.S. Federal motor vehicle safety standard (FMVSS 214) to the European Union (EU) side impact directive 96/27/EC. Eight vehicles marketed in the U.S. were tested in the EU test conditions. The level of safety performance of the vehicles based on the respective injury measures of the European and U.S. side impact regulations was assessed.
This series of comparative testing, presented in this report, with current U.S. production vehicles has provided important insights into the performance of vehicles when tested to the requirements of the FMVSS 214 and EU 96/27/EC regulations. However, it can only be viewed as a partial step in determining the overall safety performance of vehicles relative to the two regulations. Results of the current testing showed that the eight vehicles tested were not ranked similarly by their performance in each regulation when using each regulation's performance limits as the "yardstick" for comparison. Ideally, such a comparison of performance using data sets containing different injury criteria would be done by examining the probability of injury indicated by the measured injury criteria. However, updated injury risk curves were not available for the European chest injury criteria. Additionally, a measurement anomaly in the European test dummy (Eurosid-1) related to the rib displacement was present in most, if not all, tests. This anomaly, along with the limited amount of comparative test data, did not allow a positive determination of functional equivalence of the two side impact standards. These results also brought into question the biofidelity of the current European regulation dummy's chest. Recent developments in rib module design show promise in partially alleviating this problem.
What cannot be concluded from this set of testing is whether vehicles designed to meet the EU regulation will meet the U.S. regulation. This would require further tests. It is important to note that this series of tests is only one part of a general matrix needed to assess the comparative performance of vehicles relative to the two regulations. The general matrix would include testing of European production vehicles to determine how well such vehicles perform relative to FMVSS 214. The matrix would also include testing of vehicles designed for both U.S. and European markets to the requirements of both regulations. Vehicles equipped with side air bag systems would also be part of this matrix as they are becoming prevalent in both the U.S. and European fleet. Moreover, a small number of vehicles were tested in this series. A larger number of U.S. production vehicles that more broadly represent the U.S. fleet may need to be tested.
In this report, the development of a next generation side impact dummy is discussed relative to its possible harmonized use in both future U.S. and foreign regulations. An overview of the changing U.S. side impact crash environment due to the increased market share of light trucks, vans and sports utility vehicles (LTVs) is also presented. A large portion of the current U.S. side impact casualties results from impacts with the LTV class of vehicles. The lighter and less stiff EU moving deformable barrier (EUMDB) is less representative of the current and future mix of U.S. vehicles. Therefore, side impact countermeasures based on the EU barrier may not lead to real safety benefits.
An updated NHTSA research and development plan is presented which investigates the possibility of a harmonized dummy and test procedure changes which seek safety benefits related to more closely simulating the current U.S. crash environment.
The results of the current testing, in particular the measurement anomalies in the Eurosid-1, do not support a positive determination of functional equivalence of the two side impact standards. With the current changing U.S. side impact crash environment and questionable Eurosid-1 performance, it appears that the agency's resources would be better utilized in efforts to improve FMVSS 214. These efforts will include working with the European community in upgrading the Eurosid-1 dummy. The international harmonization goal of the agency is to reach agreement on the dummy and injury criteria, regardless of the differences in regulations that may be necessary due to the differences in the traffic environment, i.e., the vehicle fleet and traffic characteristics. Details and schedules for improving occupant protection in side impacts and for international harmonization are provided in the agency's Research Plan.
The following provides a summary of the findings from the matched-pair full vehicle tests and the agency's current position on side impact harmonization:
NHTSA is working towards the near term use of an upgraded Eurosid-1 (Eurosid-2) in harmonization with the European Community. However, NHTSA is not convinced that harmonization to the EU test procedure and MDB will improve the safety of U.S. motorists. In view of this, upgrading FMVSS 214 will be given significantly higher priority than international harmonization.
1. Introduction
2. Review of Current U.S. and European Side Impact Standards
3. Comparative Testing of Regulation
3.1 Vehicle Matrix
3.2 Test Results Summary and Conclusions
3.2.1 Dummy Measurement Anomaly
3.2.2 Vehicle Rankings
3.2.3 Front Seat Impact Severity
3.2.4 Rear Seat Impact Severity
3.2.5 Crush Profiles
4. Initial Assessment of Functional Equivalence
5.1.1 AAMA/AIAM/IIHS Petition
5.1.2 Advocates for Highway Safety Petition
5.2 Current Global Research and Harmonization Activities
5.2.1 International Harmonized Research Activities (IHRA)
5.2.2 Auto Safety Community
The National Highway Traffic Safety Administration (NHTSA) has long recognized the need for international harmonization of side impact requirements and the potential of added safety benefits resulting from such harmonization. Although the U.S. and EU side impact regulations address the same safety problem, they differ in test procedures, barriers, dummies, and injury criteria. Also, manufacturers have stated that these differences lead to different vehicle designs, thus posing financial burdens in terms of dual development, testing, manufacturing and distribution of vehicles in various markets.
On September 16, 1996, the U.S. Congress directed NHTSA to study the differences between the U.S. and proposed European side impact regulations and to develop a plan for achieving harmonization of these regulations. NHTSA submitted a side impact harmonization plan to the U.S. Congress in April of 1997 [1]. Figure 1 is the flowchart of the harmonization plan submitted with the Congressional report. This report serves as the first status report on side impact harmonization and responds to the September 1998, Senate Appropriations Committee, Report 105-249, in which Congress further directed NHTSA to provide a report to the House and Senate Committees on Appropriations by December 15, 1998, on progress in addressing side impact harmonization issues. The specific language in Report 105-249 is:
"Side impact standard harmonization. - In the conference report accompanying the fiscal year 1997 bill, the conferees noted that there are substantial differences between the U.S. side impact standard and a similar European requirement. The report notes that 'these differences are inconsistent with the need for the international harmonization of motor vehicle safety standards', and directed that a report be provided on NHTSA's plan for achieving harmonization of the side impact rule. The Committee is concerned that NHTSA is not moving forward more aggressively on this matter, particularly since a harmonized standard could result in a safety improvement for U.S. motorists. Therefore, the committee directs NHTSA to use funds made available in the vehicle safety performance standard program budget for development of a harmonized side impact standard so long as the Administrator is convinced that such a harmonization effort will improve the safety of U.S. motorists. The Committee directs NHTSA to report to the House and Senate Committees on Appropriations by December 15, 1998, on progress in addressing this issue."
The focus of this report is NHTSA's activities and accomplishments since submission of the harmonization plan to Congress in April 1997. Tentative conclusions regarding the difficulties for near term harmonization are presented. Discussions of international activities which are underway to establish consistency in dummy design, injury criteria, and aspects of the test conditions are presented. Details of NHTSA's short and long term research plans are given.
Figure 1 - Flowchart of NHTSA's Side Impact Harmonization plan.
To begin the process of international harmonization NHTSA initiated a research program by testing eight U.S. production Federal Motor Vehicle Safety Standard 214; - Side Impact Protection (FMVSS 214) compliant vehicles to the EU Directive 96/27/EC requirement. This is schematically represented by the dashed "START" box in Figure 1. Based on the results of this testing the plan proceeds into a process of assessing whether the safety performance of vehicles is functionally equivalent relative to the European regulation (EU Directive 96/27/EC) and the FMVSS 214.
The Functional Equivalence Assessment Process was developed in coordination with foreign governments, industry and consumer groups. NHTSA has recently published a final rule institutionalizing the process [2]. The final rule sets forth the process that the agency will use in comparing U.S. and foreign vehicle safety standards and in determining appropriate rulemaking response, if any. The rule reaffirms NHTSA's policy of actively identifying and adopting those foreign vehicle safety standards that result in significantly higher levels of safety performance than the counterpart U.S. standards. The rule also outlines the agency's policy in the case where the comparison indicates that the foreign standard's safety benefits are approximately equal to those of a counterpart U.S. standard.
This report will describe the results of the EU regulation testing as it compares to the U.S. regulation in terms of the level of safety performance of the vehicles tested under both regulations and the subsequent relationship to functional equivalence.
2. Review of Current U.S. and European Side Impact Standards
The U.S. regulation on side impact, FMVSS 214 [3], addresses thoracic and pelvic fatalities and injuries in vehicle crashes. The dynamic requirement, or crash test portion of this standard, was added in October of 1990. It was phased-in beginning with 1994 model year (MY) cars such that all new cars by the 1997 MY had to meet the requirement. Starting with the 1999 MY, trucks, buses, and multipurpose passenger vehicles less than or equal to 2,721 kg (6000 lbs) must meet the dynamic part of this standard [4].
The European Union (EU) side impact regulation, EU Directive 96/27/EC was approved in October of 1996. It applies to new and redesigned M1 and N1 vehicle types beginning with the 1999 MY. M1 vehicles are those with a capacity of nine or less occupants and would include passenger cars, multipurpose passenger vehicles, and mini buses. N1 vehicles are those with the capacity of carrying up to 3.5 metric tons, e.g. vans and chassis cabs. Vehicles with an R-point (seating reference point) of the lowest seat exceeding 700 mm from the ground are excluded. All M1 and N1 vehicles starting in the 2004 MY must meet this regulation.
The test procedures of both regulations are similar only to the extent that a stationary test vehicle is struck with a moving deformable barrier (MDB). These dynamic test procedures focus on the measurement of anthropomorphic test dummy responses to compute injury criteria. However, the two regulations use different test procedures, barriers, dummies, and injury criteria. Figures 2 and 3 show a schematic of the test setup for the U.S. and EU regulations. Table 1 compares the relevant crash test parameters such as impact direction, impact velocity and barrier face dimensions.
 Figure 2. FMVSS 214 Side Impact Test Configuration |
 Figure 3. EU 96/27EC Side Impact Test Configuration |
The FMVSS 214 dynamic test simulates the 90 degree impact of a striking vehicle traveling 48.3 km/h into a target vehicle traveling perpendicular to the striking vehicle at 24.2 km/h. This is achieved by a moving deformable barrier with all wheels rotated 27 degrees (crab angle) from the longitudinal axis, impacting a stationary test vehicle with a 54 km/h closing speed. For a typical passenger car, the left edge of the FMVSS 214 MDB (214MDB) is 940 mm forward of the mid point of the struck vehicle wheel base.
In the EU 96/27/EC dynamic test, the European MDB (EUMDB) impacts the target vehicle at 50 km/h and 90 degrees with no crab angle. This differs from FMVSS 214 in that no attempt is made at simulating the two vehicle moving collisions. The lateral striking position is aligned with the occupant seating position rather than the vehicle wheelbase. The EU MDB is centered about the R-point or seating reference point defined as the H-point for lowest and rearmost driving seat position. Under such conditions the A/B pillar engagement by the barrier will depend on the vehicle size (wheelbase).
Table 1.
Crash Test Parameter Comparison
| EU 96/27/EC | FMVSS 214 | |
| MDB Mass | 950 kg | 1367 kg |
| Velocity Vector | 50 kph/90 | 54 kph/63 |
| Impact Point | Centered on R-point* | 940 mm from wheelbase center |
| Barrier Face Ground Height |
300 mm | 279 mm Bumper 330 mm |
| Face Width | 1500 mm | 1676 mm |
| Barrier Material | Performance Defined | Aluminum Honeycomb |
*same as seating reference point
2.1 FMVSS 214 and EU 96/27/EC Movable Barriers
The dimensions and material characteristics of the 214MDB face are shown in Figure 4. The aluminum honeycomb of the barrier face is specified by design. The bottom edge of the MDB is 279 mm from the ground. The protruding portion of the barrier simulating a bumper is 330 mm from the ground. The 214MDB has a total mass of 1367 kg initially derived from the weights of passenger cars and lights trucks in the U.S. fleet with a adjustment made assuming a downward trend in vehicle mass due to fuel economy needs [5, pg IIIA-6]. The dimensions of the EUMDB face are given in Figure 5. The European barrier face is segmented into six blocks with force deflection performance characteristics specified in the EU regulation. The lower blocks are stiffer than the top blocks and the center blocks are stiffer than the outboard elements. The EUMDB face is about 20% smaller than the 214MDB in terms of face area. It is also much softer than the 214MDB face on the blocks closest to the sides. The bottom edge is the most forward part of the European MDB and is 300 mm from the ground. The European barrier has a mass of 950 kg, 40% less than the mass for the U.S. barrier.
 Figure 4. FMVSS 214 Side Impact
Deformable Barrier Face. |
 Figure 5. EU 96/27/EC Side Impact
Deformable Barrier Face |
2.2 FMVSS 214 and EU 96/27/EC Dummies and Injury Criteria
In both regulations, successful test performance is determined by dummy injury criteria. However, the regulations differ in both the test dummy and injury criteria. Figure 6 is a schematic of the two side impact dummies, the U.S. side impact dummy (SID) used in FMVSS 214 and the EU dummy (EUROSID-1) used in Directive 96/27/EC.
Although both dummies ideally represent a 50th percentile side impact anthropomorphic device, they are based on different designs and have different measurement capabilities. In particular, Eurosid-1 has an articulating half arm, while the response of the arm is molded into the design of the thorax in SID. FMVSS 214 requires that a SID be placed in both the front and rear seats of the test vehicle. The EU Directive requires that only one EUROSID-1 be placed in the front seat. The injury criteria for each regulation, given in Table 2, relate to the measurement capabilities of the dummy used.
|
|
|
SID was designed to measure only the acceleration of the ribs, spine and pelvis to compute thoracic and pelvic injury criteria [6]. The rib and spine accelerations are combined into a single metric called the Thoracic Trauma Index (TTI(d)) which has an 85g limit for 4-door passenger cars and all LTVs. The TTI(d) limit is 90g for 2-door passenger cars. The pelvic acceleration (PelvicG) has a 130g limit.
EUROSID-1 has additional measurement capabilities than SID, including force and displacement as well as acceleration based readings [7]. The EU regulation places limits on five dummy criteria to determine vehicle performance. The head protection criteria (HPC) specified is that which is generally used for frontal impact protection and is derived from head acceleration over a head contact time duration and must remain below 1000. A rib deflection criterion (RDC) allows a maximum of 42 mm of deflection in the thorax. A soft tissue viscous criterion (V*C), computed from combined rib deflection and velocity, is to be reported with a proposed limit of 1 m/s. It is worth noting that for the first two years in which EU 96/27/EC becomes effective, V*C values are to be reported but not used as a pass/fail criterion. A review of the EU directive is planned in the year 2000 during which the status of V*C as a required injury criteria will be decided. The abdominal peak force (APF) is limited to 2.5 KN. Finally, the pubic symphysis peak force (PSPF), which is in the pelvic region, must be less than 6 kN.
3. Comparative Testing of Regulation
3.1 Vehicle Matrix
Table 3 lists the annual production of U.S. made vehicles that were tested to the EU 96/27/EC requirements. The vehicles were identical in design to vehicles tested to FMVSS 214 in the NHTSA compliance test program. The matrix included four 4-door and four 2-door passenger cars. The vehicles were selected to provide a range of marginal to good performers relative to FMVSS 214 and to represent as many manufacturers as possible.
Table 3.
FMVSS 214/ EU 96/27/EC Test Matrix
| Vehicle | FMVSS 214 test | Side NCAP | Production | |
| 1997 Lexus SC300 | 2-Dr | 1995 | No | 13K |
| 1997 Ford Mustang | 2-Dr | 1996 | No | 170K |
| 1997 Mitsubishi Eclipse | 2-Dr | 1996 | No | 111K |
| 1995 Geo Metro | 2-Dr | 1996 | No | 58K |
| 1996 Ford Taurus* | 4-Dr | 1996 | Yes | 539K |
| 1995 Volvo 850 SW | 4-Dr | 1995 | No | 63K |
| 1997 Hyundai Sonata | 4-Dr | 1996 | Yes | 15K |
| 1997 Nissan Sentra | 4-Dr | 1996 | Yes | 72K |
*The EU test for the 1996 Taurus was performed by Ford Motor Company.
3.2 Test Results Summary and Conclusions
A broad overview of the test results is presented in this section. Much greater detail and analysis can be found in the agency's Experimental Safety of Vehicles (ESV) paper on this topic, which is attached in Appendix B [8]. With the exception of placing a Eurosid-1 dummy in the rear outboard position, the procedures of the EU 96/27/EC Directive were followed in performing the European side impact tests of the FMVSS 214 compliant vehicles. In addition, experts from TNO, Netherlands, provided training on the latest dummy seating practices. They also provided guidance on common EU 96/27/EC test set up practices, especially in areas where the EU directive is not specific. This series of comparative testing with current U.S. production vehicles has provided important insights into the performance of vehicles when tested to the requirements of the FMVSS 214 and EU 96/27/EC regulations. However, it can only be viewed as a partial step in determining the overall safety performance of vehicles relative to the two regulations. The following are concluded from this series of tests:
3.2.1 Dummy Measurement Anomaly
Conclusions based on this testing may not be valid due to the displacement measurement "flat-top" anomaly in the Eurosid-1.
The agency was aware that measurement anomalies had previously existed in earlier designs of the Eurosid-1. However, the intent of this testing was to assess the EU directive as presently in effect relative to the existing U.S. standard. The Eurosid-1 dummies were procured from the official European manufacturer (TNO). TNO provided assistance in assuring that the procured devices met all calibration requirements.
The measurement anomalies (plateaus or "flat-tops" on the test data plots, illustrated in Figure 7) appear to be present for the Eurosid-1 in the driver position for all the vehicles tested. These "flat-tops" appear to be present for the rear dummy in three of the six vehicles. The displacement levels of these plateaus range anywhere from 15 to 50 mm and are below the full range of the measurement capabilities of the Eurosid-1. The "flat-tops" cast doubt on the validity of EU 96/27/EC rib deflection and V*C injury criteria values.
Very recently, NHTSA initiated testing of the Eurosid-1 with prototype modification to the ribs utilizing ball bearing cylinders in the posterior piston cylinders. This modification was developed by Advanced Safety Technologies Corporation (ASTC) to reduce the flat-topping behavior. Results to-date indicate a significant reduction in the "flat-tops" and a subsequent increase in maximum rib displacements. However, vehicle impact and pendulum tests indicate that the shoulder design may still be playing a part in the abnormal rib displacement and continue to induce "flat-tops". These results are documented in a technical paper published in the 1999 SAE International Congress and Exposition and is attached in Appendix C [12].
FMVSS 214 and EU 96/27/EC did not provide similar vehicle performance rankings or pass/fail based on their respective criteria. Some vehicles performed well under both regulations.
Based on this series of comparative testing, FMVSS 214 and EU 96/27/EC did not provide similar vehicle performance rankings nor pass/fail results based on the respective thoracic and pelvic criteria (see Tables 10., 11.,and 12.). In some cases, the ranks are based on a very small difference between the performances of two vehicles. It is not possible to determine if these differences are statistically significant because they are based on the results of a single test. All vehicles tested had complied with the requirements of FMVSS 214 based on previous tests. However, three out of these eight vehicles failed one or two of the EU criteria for the driver based on the deficient measurements.
Table 10.
FMVSS 214 vs EU 96/27/EC Criteria: Pass/Fail (P/F)
| Vehicle | Dr | 214 P/F | 214 80%* | EU P/F | EU 80%* |
| Lexus SC300 | 2 | P | P | P | P |
| Ford Mustang | 2 | P | P | P | F |
| Mitsubishi Eclipse | 2 | P | F | F | F |
| Geo Metro | 2 | P | F | F | F |
| Ford Taurus | 4 | P | P | P | F |
| Volvo 850 SW | 4 | P | P | P | P |
| Hyundai Sonata | 4 | P | F | P | P |
| Nissan Sentra | 4 | P | P | F | F |
* 80% = Exceed 80% of Criteria
Considering the vehicle rankings for the 4-Dr vehicles based on the driver dummy criteria, FMVSS 214 TTI(d) rated the Hyundai Sonata as fourth, while the EU RDC rated the Sonata as first and the V*C rated it as second. Based on real-world performance of vehicles in the U.S. fleet, it must be noted that larger vehicles typically perform better in side crashes than smaller vehicles. Rankings based on the pelvic criteria for the 4-Dr vehicles were a much better match with only the third and fourth position switched.
Table 11.
FMVSS 214 vs EU 96/27/EC 4-Dr Vehicle Rankings: Driver
| Vehicle | TTI rank | RDC rank | V*C rank | PelvG rank | PSPF rank |
| Volvo 850 | 1 | 2 | 1 | 1 | 1 |
| Ford Taurus | 2 | 3 | 3 | 2 | 2 |
| Nissan Sentra | 3 | 4 | 4 | 3 | 4 |
| Hyundai Sonata | 4 | 1 | 2 | 4 | 3 |
Table 12.
FMVSS 214 vs EU 96/27/EC 2-Dr Vehicle Rankings: Driver
| Vehicle | TTI rank | RDC rank | V*C rank | PelvG rank | PSPF rank |
| Ford Mustang | 1 | 2 | 3 | 1 | 4 |
| Lexus SC300 | 2 | 1 | 1 | 2 | 1 |
| Geo Metro | 3 | 3 | 2 | 3 | 3 |
| Mitsubishi Eclipse | 4 | 4 | 4 | 4 | 2 |
As to vehicle rankings for the 2-Dr vehicles based on the driver dummy criteria, there was a good match for the thoracic criteria, with only the first and second position switched. Rankings based on the pelvic criteria were a poor match. PelvicG rated the Ford Mustang as first while PSPF rated the Mustang as fourth. PelvicG rated the Mitsubishi Eclipse as fourth, while PSPF rated the Eclipse as second.
It is worth noting that the Volvo 850 which ranked first among the 4-Dr vehicles for all the injury criteria of both regulations, with the exception of ranking a close second for RDC, was the only vehicle in the matrix which was designed to meet both regulations. In addition, it has a side mounted air bag system. As to the Lexus SC300, which ranked first or second among the 2-Dr vehicles for both regulations, it was actually designed to meet FMVSS 214. Its good performance relative to the EU requirements may be attributed to its inherent design, with a wider track and considerable crush space between the occupant and inner door, and between the inner and outer door. Based on these results, it can be concluded that some vehicles designed to meet FMVSS 214 may not meet EU 96/27/EC. However,some vehicles designed to meet FMVSS 214 performed well under both regulation indicating that vehicles can be explicitly designed to do so.
3.2.3 Front Seat Impact Severity
With the caveat of questionable EU thoracic injury criteria, results from the driver dummies indicate a higher normalized chest deflection reading in the EU tests than a normalized TTI(d) value in the FMVSS 214 tests(1).
Normalization of the dummy measures is done by dividing the dummy readings by the performance limit such that a normalized value greater than one exceeds the limit. With the caveat that the Eurosid-1 rib deflections which form the basis for computing RDC and V*C are questionable (Refer to section 3.2.1 above), the following observations are made. For the 4-Dr vehicles, the Nissan Sentra driver dummy, exceeded the RDC and V*C criteria. For the 2-Dr vehicles driver dummy, the Geo Metro exceeded RDC and the Mitsubishi Eclipse exceeded both RDC and V*C.
With the exception of the Hyundai Sonata and the Lexus SC300, the normalized TTI(d) was on the average 26.8% lower than RDC for the driver dummy. For the Sonata and the SC300, TTI(d) was 12% and 3% higher than RDC. As to V*C, the results were more of a mismatch, with normalized TTI(d) on the average 27.1% lower than V*C for the driver dummy for four of the vehicles and higher by 27.5% for the remaining four vehicles. There were no apparent trends in these differences for either the 2-Dr or 4-Dr sets of vehicles.
It cannot be concluded from the normalized chest injury results that the EU regulation is more severe or provides greater safety benefits than FMVSS 214 (see section 3.3.6). One may expect that since FMVSS 214 is in place, the manufacturers have optimized their vehicle designs to meet this regulation rather than the EU regulation.
3.2.4 Rear Seat Impact Severity
The EU tests showed much lower rear dummy normalized injury measures than in the FMVSS 214 tests for both thoracic criteria.
Although no rear seat occupant protection is required in the EU directives, a Eurosid-1 dummy was placed in the rear seat in these tests to allow a comparison of the two standards for rear seat occupants. However, since the impact location of the barrier is determined on the basis of the R-point for the front dummy, the tests show that a Eurosid-1 dummy placed in the rear seat in the EU procedure undergoes a relatively less severe impact than that seen by the rear SID in FMVSS 214 procedure, based on the normalized injury criteria in each regulation. None of the rear dummy thoracic criteria exceeded their limits. With the exception of the Geo Metro, the normalized TTI(d) was on the average 82% higher than RDC for the rear dummy. For the Geo Metro the TTI(d) was 3.9% lower than the RDC. The reason for this is mainly the combination of the EUMDB barrier design (softer on the sides) and uncrabbed 90 impact of the EU test conditions. This problem will be exacerbated in large cars. The current U.S. crash environment (based on a 1988-1996 NASS/CDS and FARS study) indicates that rear occupant severe injuries (MAIS 3) account for 7.3% of the total severe injuries and 5.1% of the overall fatalities. These low injury rates are mainly due to the low rear seat occupancy rates. Nevertheless, it is desirable to require a certain level of protection for the rear occupant by the placement of a rear dummy in a dynamic side impact safety standards, particularly because children often ride in the rear seat.
The EU test vehicle crush profiles were significantly different from those observed in FMVSS 214 tests.
In order to facilitate comparison with the intrusion profile in the FMVSS 214 tests, pre and post test side crush measurements were collected for the EU tests as specified in the FMVSS 214 test procedure [9]. The maximum and average side crush at the door sill and mid door levels for the EU and FMVSS 214 tests are presented in Table 8. The EUMDB is 176 mm or 10.5% narrower than the 214MDB and in the EU procedure it is centered on the driver seating reference point while the 214MDB is positioned more forward and is positioned relative to the center of the wheelbase. This resulted in no MDB to A-pillar engagement in the EU tests while the A-pillar was engaged in all of the FMVSS 214 tests. Examples of the static crush profiles at the door sill and mid door levels are presented in Figures 8 and 9.
In general, the crush profile for the EU tests is more rounded with larger intrusion around the B-pillar and the rear section of the front door. In the FMVSS 214 tests, the crush profile is more rectangular in shape with the intrusion more evenly distributed along the area of MDB-to-vehicle engagement. This is attributed to the characteristics of the EUMDB and 214MDB and their positioning as described earlier. At both the mid-door and sill levels, the FMVSS 214 tests provided the largest average intrusion in five of seven cases. The average vehicle intrusion across the seven vehicles was 260 mm and 223 mm at the H-point and mid-door levels, respectively, for FMVSS 214 as opposed to 232 mm and 213 mm for the EU test. The average across the seven vehicles of the peak vehicle intrusion was greater for the EU tests at all three door levels. In 1991, Dalmotas et al. reported that in a series of vehicle tests performed by Transport Canada, the vehicle deformation patterns or side crush profiles produced by the 214MDB in the immediate proximity of the driver's seat showed closer agreement with vehicle to vehicle damage patterns than those produced by the EUMDB [10].
Figure 8
Figure 9
Side Intrusion at Door Sill, Driver H-point, & Mid-Door
| Vehicle | Door Sill Level
max and average crush (mm) |
Driver H-pt
level
max and average crush (mm) |
Mid-Door level
max and average crush (mm) | |||
| FMVSS 214 |
EU 96/27/EC |
FMVSS 214 |
EU 96/27/EC |
FMVSS 214 |
EU 96/27/EC | |
| Lexus SC300 | 157
109 |
130
100 |
320
272 |
330
216 |
351
239 |
304
193 |
| Ford Mustang | 132
99 |
266
153 |
254
220 |
333
211 |
234
171 |
335
197 |
| Mitsubishi Eclipse | 178
157 |
196
107 |
304
287 |
333
265 |
296
258 |
333
248 |
| Geo Metro | 160
112 |
112
70 |
239
227 |
249
179 |
226
161 |
262
141 |
| Ford Taurus* | N/A | N/A | N/A | N/A | N/A | N/A |
| Volvo 850 SW | 110
70 |
150
69 |
284
220 |
264
178 |
280
227 |
270
189 |
| Hyundai Sonata | 147
91 |
281
164 |
388
326 |
443
291 |
394
332 |
435
305 |
| Nissan Sentra | 166
125 |
217
120 |
310
270 |
372
287 |
280
172 |
377
217 |
| Average
(n = 7) |
150
109 |
193
112 |
300
260 |
332
232 |
294
223 |
331
213 |
* Crush profile data was not available for the Taurus EU test.
** Bold numbers indicate highest value measured, FMVSS vs EU.
3.2.6 Limitation of Current Study
It cannot be concluded from this set of testing that vehicles designed to meet the EU regulation will meet the U.S. regulation. This would require further tests.
It is important to note that this series of tests is only one part of a general matrix needed to assess the comparative performance of vehicles relative to the two regulations. The matrix should include testing of European production vehicles designed to no requirements and those exclusively designed to meet the EU requirements only to determine how well such vehicles perform relative to FMVSS 214. The matrix should also include testing of vehicles designed for both U.S. and European markets to the requirements of both regulations. Vehicles equipped with side air bag systems would also be part of this matrix as they are becoming prevalent in both the U.S. and European fleet. In addition, since manufacturers are beginning to design their vehicles for improved performance in the U.S. New Car Assessment Program (NCAP), testing of vehicles to similar higher severity test conditions for both regulations may also be needed. Moreover, a small number of vehicles were tested in this series. A larger number of U.S. production vehicles that more broadly represent the U.S. fleet, including large passenger cars and LTVs, may need to be tested.
4. Initial Assessment of Functional Equivalence
From NHTSA's perspective, in basic terms, a foreign vehicle safety standard is considered functionally equivalent to a counterpart U.S. standard when the two standards address the same safety need and provide similar safety benefit in the U.S. crash environment. Relative to the European and U.S. side impact regulations, FMVSS 214 has only recently been in full effect for passenger cars (MY 1997) and LTVs (MY 1999), and EU 97/26/EC is not yet in effect in Europe. As such, there is currently insufficient real world safety data to assess the effectiveness of either regulation, whether in the U.S. or European real world environments.
Data from compliance testing, such as the series presented in this report, can be used as a surrogate. Injury risk curves would be used to assess occupant risk in the real world from the computed injury criteria obtained via crash testing. Currently, injury risk curves are not available for the abdominal, pelvic, and lateral head impact EU injury criteria(2). In addition, due to the volume and quality of the earlier injury and impact data, the EU injury risk functions originally developed for the thoracic region may need to be improved [11]. Moreover, the thoracic injury risk functions were based on the responses of the production prototype of the Eurosid dummy and may need to be updated for the production Eurosid-1 or a modified Eurosid-1.
In addition, the aspect of how well the test conditions and movable deformable barrier of the EU regulation represent the real world U.S. crash environment cannot be overlooked when assessing the relative safety benefit of the two standards. A dynamic crash test requirement in a safety regulation should simulate the crash environment to the greatest extent possible. More importantly, the dynamic requirement should provide for realistic injury causing mechanisms. The representativeness of the EUMDB as the striking vehicle must be considered, because a large portion of the U.S. side impact casualties are the result of impacts with LTVs. LTVs have become a significant and a growing segment of the U.S. fleet. If an LTV strikes a vehicle in the side it is twice as likely to cause death or injury than if a car strikes a vehicle in the side. The adequacy of both the FMVSS 214 and the EU movable deformable barrier in representing the striking vehicle in the current and future U.S. crash environment is in question. In particular, the lighter and less stiff EU barrier is less representative of the current and future mix of U.S. vehicles. Therefore, side impact countermeasures based on the EUMDB may not lead to real safety benefits in the United States.
Given the results of the current testing, in particular the measurement anomalies in the Eurosid-1, the data do not support a positive determination of functional equivalence of the two side impact standards. Further, an ideal comparison of the two test procedures and requirements would necessitate a complement of vehicles of all sizes that are known to be designed to meet either FMVSS 214 or EU 96/27EC. This testing would require significant funding to pursue. In light of the current changing U.S. side impact crash environment and questionable Eurosid-1 performance, the agency's resources may be better utilized in efforts to improve FMVSS 214. Such proposed efforts are outlined in section 6. and are believed to be more likely to result in tangible safety benefits than the pursuit of functional equivalent determination at the current time.
On December 22, 1997 the American Automobile Manufacturers Association (AAMA), Association of International Automobile Manufacturers (AIAM), and the Insurance Institute for Highway Safety (IIHS) submitted to NHTSA a petition for rulemaking on FMVSS 214. The petitioners request that amendments be made to FMVSS 214, Part 572 - Anthropomorphic Test Dummy, Side Impact and Part 587 - Moving Deformable Barrier such that: all new vehicles manufactured after September 1 of the calender year that is seven years after publication of the final rule shall comply with a modified version EU Directive 96/27/EC; effective immediately with publication of the final rule, manufacturers have the option of certification either to the dynamic requirements of current version of FMVSS 214 or the requirements of the modified EU Directive.
The modified EU Directive was defined by the petitioners as: EU 96/27/EC appropriately modified to specify an upgraded EUROSID-1 in the vehicle front seat at mid-point of its travel and an upgraded EUROSID-1 in the rear seat. The petitioners recognize essentially the same problems with the present Eurosid-1 as noted in the NHTSA test series (i.e., measurement anomalies indicated by "flat-topping" due to design deficiencies.) The petitioners also asked that NHTSA enforcement tests be performed using the same option chosen by the manufacturer and that lateral NCAP testing use the same test option that the manufacturer used to certify a given vehicle.
The petitioners stated that they were prepared to join in appropriate discussion, testing or data analysis to expedite agency action on the petition. They requested that NHTSA participate with governments, research organizations, and manufacturers worldwide to develop the next generation mid-size male side impact dummy. The petitioners have endorsed the pertinent ISO/TC22 resolution and support the ISO/TC22/SC12/WG5 working group as a forum to specify and design such a dummy. Finally, they urged NHTSA to adopt an upgraded EUROSID-1 and to work jointly with the Commission of the European Union for adoption of an upgraded package in both the EU Directive and the ECE Regulation.
Based on the results of NHTSA's set of EU tests, a need to resolve the issues for upgrading the Eurosid-1, and the concerns of side impact protection in the rapidly changing U.S. fleet, the agency has not been able to grant this petition. However, the agency, as detailed in the research plan, is working toward the near term use of an upgraded Eurosid-1 (Eurosid-2) for harmonization with the European community. In Section 5.2, a discussion of the international harmonization activities is presented.
5.1.2 Advocates for Highway Safety Petition
On July 2, 1998, Advocates for Highway and Auto Safety (Advocates) submitted a petition for rulemaking requesting NHTSA to upgrade Standard 214. In its petition, Advocates argues that the current dynamic side impact requirements of Standard 214 are insufficient to provide adequate protection to occupants of passenger cars and small LTVs and, therefore, recommends several ways in which NHTSA could amend the standard to increase the safety of occupants of those vehicles when they are struck in lateral collisions by larger, heavier and more aggressive vehicles.
The petitioners allege that the current regulation has several major deficiencies. They contend the 85/90 TTI(d)criteria are not stringent enough, explaining that neither the occupants of passenger cars nor small LTVs are being provided adequate protection when their vehicles are struck by higher, heavier, and more aggressive LTVs. Also they believe the MDB is not high/heavy enough because the barrier weight/height were originally designed for a vehicle fleet that was projected to be lighter and smaller than the current fleet. They state that since 1988, the passenger car fleet has not changed significantly while the LTV fleet has grown in average weight and number. The average weight difference between the passenger cars and LTVs was 1,000 lbs in 1993 up from 700 lbs when the MDB design was determined in 1988. They expect that this weight disparity will continue to grow in the future. Finally, they think that Eurosid-1 has advantages to SID because of additional measurement capability.
The petitioners propose that NHTSA consider rulemaking to raise the overall level of side impact protection at a cost that would be reasonable and acceptable to manufacturers and consumers. They recommend the following: amending FMVSS 214 to a higher safety performance level such that superior side impact air bags would be developed and installed in vehicles as standard equipment; replace the quasi-static door crush test with a side-to-pole impact test like the recent FMVSS 201 upgrade; lastly, replace SID with Eurosid-1.
The agency has granted the petition because it believes that current planned side impact research activities will fully address the issues in the petition.
5.2 Current Global Research and Harmonization Activities
5.2.1 International Harmonized Research Activities (IHRA)
A number of federal governments worldwide, including the U.S., Canada, the European Union, and Japan, have joined forces under the IHRA to conduct research, the results of which may form the basis for future harmonized standards. The IHRA provides a forum for cooperation among the governments of member countries to conduct research on various topics of interest.
To address worldwide harmonization in side crash protection and a related request from the European Experimental Vehicle Committee (EEVC), NHTSA recently received approval for the IHRA steering committee to include side impact research under IHRA activities. During the 16th ESV conference in June 1998, the IHRA Steering Committee approved a Side Impact Working Group (WG) within IHRA with Australia as the lead country for coordinating the side impact research activities. This working group met in September and November 1998 and is in the process of developing their research agenda. During the 16th ESV, the IHRA steering committee also directed the Biomechanics WG of the IHRA, which is under the U.S. lead, to form a Government-only ad hoc group to determine the specifications for a universal side impact anthropomorphic test device by performing the following:
a) Analyze the real world safety problem in side crashes and quantify fatalities and injuries.
b) Determine the injury mechanisms from biomechanical testing and real world studies, and establish injury criteria and associated injury risk functions.
c) Examine all available side impact dummies with regard to their biofidelity and injury risk assessment capabilities.
d) Make recommendations of the most suitable dummy, if any, and suggest modifications of those devices if needed.
The Side Impact WG is anticipated to coordinate closely with the Biomechanics WG regarding all aspects of injury criteria and dummy development.
Ongoing activities within the auto safety community have also demonstrated the need to take side impact safety research to the next level. Some of the more significant activities are:
a) The International Standards Organization (ISO) has developed performance criteria for side impact dummies, and is poised to develop a 2nd generation side impact dummy called the WorldSID, with a prototype 50th percentile male planned for the year 2000. The thrust of the ISO initiative is to develop a common dummy for use worldwide. Given the short development time frame, the upgraded dummy is expected to take the best features of existing dummies. One of the main candidates is the SID-IIs, a small adult female lateral impact dummy specifically designed to help evaluate side air bags, that was recently developed by Occupant Safety Research Partnership (OSRP) under the United States Council for Automotive Research (USCAR) consortium.
b) The European community is also aware of the need to upgrade the Eurosid-1, and has initiated the SID-2000 project, sponsored by an European Commission consortium. Recently, the European Commission approved the integration of the SID-2000 project into the ISO WorldSID work item. The SID-2000 program will reassess the European crash environment including distribution of injuries by body region, injury criteria, and the need for different size dummies.
c) In October, 1998, the EEVC submitted a letter to NHTSA "expressing the European interest to coordinate with NHTSA the necessary steps leading to a worldwide accepted interim harmonized Eurosid-2 dummy." The EEVC indicated that for most of the concerns regarding the performance of the EUROSID-1, "potential design solutions seem to exist which in a relatively short term may result in an updated EUROSID-1 with acceptable performance". The EEVC also indicated that it "has been reviewing proposed changes in the EUROSID-1 design and certification procedures in the light of the petition put forward by AAMA, AIAM and IIHS" and also suggested that "NHTSA specify which (further) changes they think are needed in the current EUROSID-1 design and send these to the chairman of the EEVC Working Group 12 "Adult Crash Dummies"." NHTSA is in the process of outlining the dummy requirements and will provide the input to EEVC shortly. In a earlier meeting, TNO staff indicated to NHTSA that TNO is committed to fixing the EUROSID-1 thorax, shoulder, and backplate to address NHTSA's main concerns regarding the EUROSID-1. The modified dummy would be called Eurosid-2. TNO indicated that the Eurosid-2 will be available by the end of the year for production but would be available to NHTSA for testing by August, 1999. NHTSA will pursue the successful upgrade of the Eurosid-1 as an interim dummy for international harmonization.
d) Several side impact thoracic and head protection air bag systems are emerging in the U.S. market and are projected to become prevalent in the fleet. These inflatable side protection systems vary widely in designs, sizes, mounting locations and methods, inflation systems, and areas of coverage. It is necessary to understand the performance and overall effectiveness of these dynamic side impact protection systems, especially in terms of any possible harmful effects and unintended consequences of side air bag deployment to children and out-of-position occupants. To gain more information about this rapidly proliferating technology NHTSA held a series of one-on-one meetings with vehicle manufacturers in late 1998 and early 1999. In December of 1998, NHTSA sent a letter to twenty-one vehicle manufacturer executives urging them to personally ensure that their side-mounted air bags are designed to "do no harm" to occupants. This was followed by a public meeting on April 19, 1999, hosted by the agency, to provide a forum for sharing available real world and test data and to explore technical issues relating to the assessment of potential benefits and risks of side inflatable protection systems.
Figure 10 shows the time line for harmonization tasks presented in the April 1997 Report to Congress. To date the first 5 tasks in Phase I have been completed. These tasks were completed approximately 6 months behind their estimated scheduled date primarily due to delays in obtaining and calibrating the Eurosid-1 test dummies. NHTSA is currently proceeding with tasks 6 through 10.
The Phase II plan as previously presented was always considered tentative and likely to be revised based on Phase I results. The test results to date indicate that the next phase of side impact research should proceed in a different direction. It is hoped that this next phase of research can lead to harmonization to the extent possible and will advance side impact safety in the U.S. fleet taking into account the level of available resources. If current efforts to merge the European SID2000 and ISO WorldSID dummy development projects succeed, it will result in an advanced harmonized side impact dummy which can be commonly produced and used world wide. As stated previously, NHTSA will pursue the successful upgrade of the Eurosid-1 to Eurosid-2 as an interim dummy for international harmonization. Harmonization research can then focus on evaluating the Eurosid-2 and/or the advanced world side dummy and its application in the next generation side impact safety standard(s). Harmonization of the dummy and injury criteria is a basic premise in achieving a global harmonized side impact regulation. While differences in the fleet composition and crash involvement may preclude totally harmonized test conditions and movable barriers, the use of a single dummy family would significantly alleviate the current burdens of vehicle design, testing, manufacturing, and distribution currently encountered by automobile manufacturers in the growing global market. It should also lead to improved side crash protection world wide.
Appendix A contains the agency's latest plan for both harmonization and upgrade of the side impact protection regulation. This supercedes Phase II of the previous research plan shown in Figure 10. The plan has both long term and short term goals. The major objectives are to improve occupant protection in both vehicle to vehicle and fixed object impacts, provide near term research to address the changing crash environment, and to conduct longer term research towards a harmonized next generation side impact test dummy and test conditions.
