The National Automotive Sampling System 

(NASS) was established in 1979 as part of a 

nationwide effort to reduce motor vehicle 

crashes, injuries, and deaths on our highways. 

NASS is operated by the National Highway 

Traffic Safety Administration (NHTSA) which is 

part of the U.S. Department of Transportation.

NASS collects crash data to help government 

scientists and engineers analyze motor 

vehicle crashes and injuries. NASS has 

detailed data on a representative random 

sample of minor, serious, and fatal crashes 

involving passenger cars, pickup trucks, vans, 

large trucks, motorcycles, and pedestrian 

crashes.

HOW NASS WORKS

NASS has two parts: the Crashworthiness 

Data System (CDS) and the General 

Estimates System (GES). Both systems select 

cases from 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.

NASS in turn is part of a larger Electronic Data 

System (EDS) which includes Special Crash

Investigations (SCI), the Large Truck Crash

Causation Study (LTCCS), the National Motor 

Vehicle Crash Causation Study (NMVCCS)

Cooperation f

law enforceme

agencies enab

NASS researche

list and select c

to be studied a

obtain police 

accident repo

(which give ke

information on 

estimates come from a larger sample of 

crashes, but only basic information from 

police accident reports is coded into a 

computer file.

CRASHWORTHINESS DATA SYSTEM (CDS)

There are 27 field research teams that study 

about 5,000 crashes a year involving

passenger cars, pickup trucks, and vans.

Since 1979, CDS has collected data on over 

140,000 crashes. Trained crash researchers

obtain data and photographs from crash sites 

collecting evidence such as skid marks, fluid 

spills, broken glass, and bent guardrails. They 

locate the vehicles involved, photograph

them, measure the crash damage and

identify interior locations that were struck by 

the occupants.

These researchers follow up their on-site 

investigations by interviewing crash victims

and reviewing medical records to determine 

the nature and severity of injuries. Interviews 

with people in the crash are conducted with 

discretion and confidentiality.

The research teams are interested only in

information that will help them understand the 

nature and consequences of the crashes. 

Personal information about individuals --

names, addresses, license and registration

numbers, and even specific crash locations --

are not included in public NASS files.

GENERAL ESTIMATES SYSTEM (GES)

General estimates come from a nationally

representative sample of police reports on

crashes of all types from minor to serious. 

Since 1997, GES has collected data on

approximately 50,000 crashes each year.

These reports are chosen from 60 areas that 

reflect the geography, roadway mileage,

population, and traffic density of the U.S. This 

information is used to estimate how many

motor vehicle crashes of different kinds take 

place and what happens when they occur.

location of the crash, the vehicles invo

and where the injured were taken for me

care). The police also may permit acce

certain roadways and crashed vehicles.

The medical communityprovides acces

records. It is the primary source of dat

the nature and severity of injuries and 

time spent recovering in the hospital.

Tow yards, garages, and city vehicle po

provide access to damaged vehicles. 

researchers photograph vehicles at 

sites, measure vehicle damage, and re

the sources of occupant injury.

Confidential interviews with people who 

in crashes provide confirmation of 

information, insights into how crashes o

the extent of injuries not treated at hosp

whether safety belts were used, and 

time lost.

Taken together, information from 

sources provide researchers with a de

profile of a crash -- from before the 

through medical care for the injured.

NASS researchers depend on the 

participation and cooperation of law 

enforcement agencies, hospitals, physici

medical examiners, coroners, tow yard 

operators, garages, city vehicle pounds, 

the individuals involved in crashes. 

and the Crash 

Injury 

Research & 

Engineering 

Network 

(CIREN).

Crashworthiness field 

researchers 

carefully study 

and record 

key aspects of 

each motor
The data collected by the CDS and GES 

research teams become permanent NASS 

records. This information is used by NHTSA for 

a variety of purposes:

•to assess the overall state of highway safety 

and identify existing and potential traffic 

safety problems;

•to obtain detailed data on the crash 

performance of passenger cars, pickup 

trucks, and vans; and evaluate vehicle safety 

systems and designs;

•to learn more about the nature of crash 

injuries and about the relationship between 

the type and seriousness of a crash and the 

resultant injuries;

•to assess the effectiveness of motor vehicle 

and highway safety program standards, and 

evaluate alcohol and safety belt use 

programs; and,

•to evaluate the effect of such societal 

changes as increased traffic flow and 

increased large truck traffic.

Information collected in NASS, with all 

personal identifiers removed, is made 

available to other researchers and 

organizations involved in the highway safety 

effort. They include other Federal agencies; 

state and local governments; universities; 

research institutions; the automobile, trucking, 

and insurance industries; and the general 

public.

INFORMATION ON NASS

For statistical publications and information, 

case data, or data files, contact:

National Highway Traffic Safety Administration

National Center for Statistics and Analysis

Information Services Branch, NPO-121

400 7th Street, S.W. 

Washington, DC 20590

(202) 366-4198 or (800) 934-8517

or 

http://wwwnrd.nhtsa.dot.gov/departments/nrd-30/ncsa/

(202) 366-7078 (FAX)

For more information on NASS technical 

operations and field procedures, contact:

National Highway Traffic Safety Administration

National Center for Statistics and Analysis

Crash Investigation Division, NPO-111

400 7th Street, S.W. 

Washington, DC 20590

(202) 366-5378 (202) 366-5374 (FAX)

AUTO SAFETY HOTLINE

Do you need information on auto safety 

re-calls, crash test results, or fuel economy 

ratings? Do you have a complaint about a 

possible motor vehicle safety defect? 

Call the Auto Safety Hotline, toll-free:

(800) 424-9393

DOT HS 807 304

Rev. APR 2005

National Automotive

Sampling System

National Center for Statistics and Ana

National Highway Traffic Safety Administ

U.S. Department of Transportation