NASS is composed of two systems - the Crashworthiness Data System (CDS) and the General Estimates System (GES). Both systems are based on cases selected from a sample of police crash reports. CDS data focus on passenger vehicle crashes, and are used to investigate injury mechanisms to identify potential improvements in vehicle design. GES data focus on the bigger overall crash picture, and are used for problem size assessments and tracking trends.

Established in 1979, NASS was created as part of a nationwide effort to reduce motor vehicle crashes, injuries, and deaths on our nation's highways.

NASS collects crash data to help government scientists and engineers analyze motor vehicle crashes and injuries. NASS collects detailed data on a representative, random sample of hundreds of thousands of minor, serious and fatal crashes involving passenger cars, pickup trucks, vans, large trucks, motorcycles, and pedestrians.

The two components which make up NASS, the Crashworthiness Data System (CDS) and the General Estimates System (GES), select cases from police crash reports (also known as PARS: Police Accident Reports) at police agencies within randomly selected areas of the country. These areas are counties and major cities that represent all areas of the United States. CDS data are collected by field researchers who carefully study and record aspects of selected motor vehicle crashes to include exterior and interior vehicle damage, occupant injury, crash scene investigation, environmental conditions at the time of the crash, etc., etc. GES data comes from a larger sample of crashes, but only basic information is recorded from the PARs and entered into the system.

NASS Special Studies

Special Studies are periodically mandated by Congress in order to study a specific element or segment of highway safety. The NASS infrastructure provides an existing means of data collection, analysis and reporting with which to satisfy the parameters of many such requests and can meet the requirements of the study while minimizing costs.