NASS Brochure

WHAT IS NASS?
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 NHTSA
electronic data system, which includes
Special Crash Investigations (SCI), the Large
Truck Crash Causation Study (LTCCS), the
National Motor Vehicle Crash Causation
Survey (NMVCCS)
and the Crash
Injury
Research &
Engineering
Network
(CIREN).
Crashworthiness field
researchers
carefully study
and record
key aspects of
each motor

vehicle crash selected: the crash location,
the vehicles, and occupants injuries. General
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 24 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
160,000 crashes. Trained crash researchers
obtain data and photographs from crash sites
collecting scene 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 60,000 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.

COOPERATION IS ESSENTIAL
NASS researchers depend on the
participation and cooperation of law
enforcement agencies, hospitals, physicians,
medical examiners, coroners, tow yard
operators, repair garages and the individuals
involved in crashes.
Cooperation from
law enforcement
agencies enables
NASS researchers to
list and select crashes
to be studied and to
obtain police
accident reports
(which give key
information on the
location of the crash, the vehicles involved,
and where the injured were taken for medical
care). The police also may permit access to
certain roadways and crashed vehicles.
The medical community provides access to its
records. It is the primary source of data on
the nature and severity of injuries and the
time spent recovering in the hospital.
Tow yards, repair garages, and impound
vehicle lots, provide access to damaged
vehicles. NASS researchers photograph
vehicles at these sites, measure vehicle
damage, and record the sources of
occupant injury.
Confidential interviews with people who were
in crashes provide confirmation of other
information, insights into how crashes occur,
the extent of injuries not treated at hospitals,
whether safety belts were used, and work
time lost.
Taken together, information from these
sources provide researchers with a detailed
profile of a crash -- from before the crash
through medical care for the injured.

HOW THE INFORMATION IS USED
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 highway
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 severity 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
Data Reporting and Information Division
NVS-424
1200 New Jersey Avenue, S.E.
Washington, DC 20590

National Automotive
Sampling System

(800) 934-8517
or
http://www.nhtsa.gov/portal/site/nhtsa/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, NVS-411
1200 New Jersey Avenue, S.E.
Washington, DC 20590
(202) 366-5378

(202) 366-3189 (FAX)

AUTO SAFETY HOTLINE
Do you need information on auto safety
recalls, 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. April 2008

RESEARCH ON
MOTOR VEHICLE
CRASHES AND INJURIES
TO SUPPORT
SAFETY PROGRAMS
National Center for Statistics and Analysis
National Highway Traffic Safety Administration
U.S. Department of Transportation