THE U.S. NEW CAR ASSESSMENT PROGRAM (NCAP):

PAST, PRESENT AND FUTURE

Lawrence L. Hershman

National Highway Traffic Safety Administration

United States

Paper Number 390

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THE U.S. NEW CAR ASSESSMENT PROGRAM (NCAP): PAST, PRESENT AND FUTURE

Lawrence L. Hershman

National Highway Traffic Safety Administration

visibility and use of NCAP information by consumers

in their buying decisions, and increased references to

NCAP information by vehicle manufacturers in their

advertisements, contribute to the manufacture and

purchase of safer vehicles and attest to the expanded

importance of NCAP. NHTSA has increased the

types of tests and the categories and numbers of

vehicles it tests and is considering the use of smaller

stature dummies in NCAP. Developmental testing has

been conducted and consideration is being given to

present status, with a reference comparison to NCAP

programs of other organizations in the U.S. and

abroad. It discusses NCAP in relation to rulemaking.

It examines NCAP’s future prospects, including

changes and additions to its testing program and the

presentation of its information, international

harmonization, program management, and strategic

issues.

INTRODUCTION

The annual death toll on America’s highways has

Department of Transportation’s National Highway

Traffic Safety Administration (NHTSA). NCAP was

designed to provide safety information to the public

and to improve occupant safety by providing market

incentives for vehicle manufacturers to voluntarily

design better crashworthiness into their vehicles.

U.S. NCAP HISTORY

NCAP was mandated under Title II of the Motor

Vehicle Information and Cost Savings Act of 1973 (15

U.S.C. §1942 et seq.) to provide information to

The second goal was to establish market forces to

encourage vehicle manufacturers to design higher

levels of safety into their vehicles.

NCAP began crash testing light trucks with the 1983

model year. NHTSA began an NCAP Optional Test

Program in 1986, in which manufacturers could

request a test or retest of a particular model based on

design changes or the introduction of innovative safety

features. The manufacturer pays the cost of this test,

which NHTSA controls at an approved test site. In

common injury-causing crash events–frontal and side

impacts. Most recently, in January 2001, NHTSA

announced its Static Stability Factor (SSF) ratings

program and published the first results of its new

rollover resistance ratings, which covered 43 model

year (MY) 2001 vehicles. In February 2001 an

additional 34 ratings were published.

TEST PROCEDURES

NHTSA chooses crash test vehicles from passenger

car, light truck, sport utility vehicle, and van models

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is tested. NHTSA uses four contractors to conduct its

Crash test results on models that have no basic

changes are carried over to the next year, so results are

available on about 85 percent of the new cars sold.

NCAP restrains test dummies within the vehicle with

all manual and automatic restraints to assess the

vehicles’ maximum crashworthiness, whereas

compliance tests use only passive restraints (automatic

belts and air bags). NCAP results do not apply to

unbelted occupants. All passive restraints available on

a vehicle (such as air bags) are kept operational in the

crashed into a fixed barrier at 56.3 kilometers per hour

(km/h) (35 miles per hour (mph)). This impact is

equivalent to a vehicle moving at 112.7 km/h (70 mph)

striking an identical parked vehicle, or equivalent to

two identical vehicles each moving toward each other

at 56.3 km/h (35 mph). NHTSA collects data on

injury potential in both NCAP and compliance tests by

measuring accelerations and forces placed on an

occupant’s head, chest, and upper leg. The lower the

numbers for the head, chest, and the femur load, the

conducted using the dummy that the manufacturer

recommended for the higher severity testing,

regardless of the dummy used in certifying compliance

to FMVSS No. 208. Switching to exclusive use of the

Hybrid III dummy has permitted the collection of

more injury data, which enables NHTSA and

manufacturers to obtain research data on the potential

for injury to other body parts. Using the Hybrid III

exclusively also eliminates potential performance

variability.

to gravity), with the maximum allowable level of 60

g’s over 3 milliseconds, or chest compression, with a

maximum reduction of three inches in the distance

between the sternum and spinal column. Femur load

measures the compressive force transmitted axially

through the upper legs, with a maximum allowable

level of 2,250 pounds of force. NHTSA concluded

that a combined effect of injury to the head and/or

chest should be used, since it is well documented that

an individual who suffers multiple injuries has a higher

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analyzed the system, especially the implied precision

Appropriations Committee requirements, NHTSA

performed a use study and in 1994 began

implementing new methods of informing consumers of

the comparative levels of the safety of vehicles

through NCAP.

These new star ratings were designed to give

consumers a quick, simplified single point of

comparison between different vehicles. The star scale

was based on a “Level of Protection Scale,” which

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serious type of automobile crashes causing injury and

death. Though only one in four crashes is a side

impact, more than one-third of seriously injured

occupants sustained their injuries from vehicle side

impacts.

NHTSA implemented a dynamic side impact

compliance test, FMVSS No. 214, in 1990. It

simulates a 90 degree side impact, in which a moving

deformable barrier, representing the striking vehicle,

moves at 53.9 km/h (33.5 mph), crabbed at 27 degrees,

type collision with a 1,367.6 kilogram (3,015 pound)

nominal weight deformable barrier moving at 62 km/h

(38.5 mph) into a standing vehicle. Side collision star

ratings indicate the chance of a life threatening chest

injury for the driver and the left rear seat passenger. If

the pelvic instrumentation in the crash test dummy

indicates a high likelihood of pelvic injury in the

lateral test, the consumer is also informed of this

possible injury. Head injury is not measured in these

tests. Since all tested vehicles are impacted by the

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same size barrier, it is possible to compare side crash

It should be noted that some SUVs tipped over when

struck during side impact collision testing. Since the

test was not designed to measure how likely a vehicle

is to rollover, NHTSA makes no prediction whether

those vehicles are more prone to rollover in side

impact crashes than other SUV models. Nonetheless,

the tests do reinforce real-world crash experience that

shows that, when struck in a side impact collision,

SUVs are more prone to roll over than other vehicle

types. It should be noted that the vast majority of

impact (to rate head protection). Japan NCAP rates

side impacts using a rating system with A/B/C/D

categories, and the A category has one subcategory,

A

, which indicates vehicles with especially good

crash test injury scores. The side crash ratings cover

injury risk to drivers, door open-ability, driver

rescuability, and fuel leakage. Australian NCAP also

rates side impact protection, performing its side impact

test into a deformable barrier at 50 km/h (31 mph).

annually. Over 60 percent of SUV fatalities occur in

rollover crashes. In December 1998, NHTSA decided

to develop consumer information on rollover

resistance via NCAP. From 1991 to 1999, NHTSA

studied both static metrics and vehicle maneuver

(dynamic) tests for their potential to describe rollover

resistance in an objective and repeatable way.

Following publication of the results of the most recent

driving maneuver test program in 1999, NHTSA

decided to use the static stability factor (SSF) as the

wheels hit a curb, soft shoulder or other roadway

object, whereas untripped rollover is caused by driving

maneuvers (entering a curve at excess speed, e.g.) –

rather than wheel contact with a tripping object.

Improvements in SSF improve both types of rollover

risk, whereas it is possible to make vehicle

adjustments that improve performance in a dynamic

maneuver test but have no positive impact on the risk

of tripped rollover. Other reasons for selecting the

SSF measure are: maneuver test results are greatly

2000 on the use of the SSF for a 5-star rating program

on the rollover resistance of light vehicles. In the

conference report on the FY2001 DOT Appropriation

Act, Congress permitted NHTSA to move forward

with the rollover rating proposal while calling for a

National Academy of Sciences study by summer 2001

to assess the validity of SSF as a rollover metric and

to compare SSF versus dynamic tests. A January 2001

notice [49 CFR Part 575, which can be found on

NHTSA’s web site at

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consumer information, recommend marketing

marketing plan.

NHTSA has taken several steps to improve the

comprehensibility and accessibility of NCAP

information provided to consumers. Originally,

NCAP test information had been presented in

technical terms such as a “Head Injury Criteria” value.

To improve consumers’ understanding of the

information, the test results for each vehicle are now

presented in an easier-to-understand five-star rating

NHTSA has successfully leveraged its limited

resources by established partnerships with several

organizations to develop and disseminate NCAP safety

ratings and other information through its brochures and

more demanding NCAP levels than at the established

standard levels.

Evidence abounds that NHTSA’s efforts have been

effective in increasing the public’s awareness and use

of the crash test ratings in purchasing a new vehicle.

Various polls show that more and more consumers are

placing a higher emphasis on a vehicle’s safety

features and performance in making their purchasing

decisions. The awareness of this consumer attitude is

reflected by the increased references to vehicle model

TV and in magazines.

NCAP has grown into a worldwide force to promote

and encourage automotive safety. The original US

initiative has led to rapidly developing consumer

information programs in Europe, Japan, and Australia.

FUTURE AND POTENTIAL NCAP

EXPANSION

The future expansion of NCAP depends on several

factors, primarily engineering science and funding.

Limited funding levels can restrict NCAP’s expansion

reality dictates that priorities will have to be

established and followed.

Even for existing tests, funding constraints limit the

number of vehicles NCAP can test. Twenty-five

percent of the e-mail on the Buying a Safer Car web

page is from consumers complaining that the vehicles

they are interested in have not been tested.

It has been suggested that NCAP could use computer-

based simulations for enhanced safety design.

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Although costly, simulated crashes allow designers to

simulate frontal, rear, and side impacts and roof

crushes. They may model a specific component and in

some cases, use nonlinear finite-element models to

simulate the entire vehicle and predict its interaction

with occupants during a collision. The simulations can

provide information on structure deformation,

intrusion into the occupant compartment, and the

forces generated by structural components. However,

computer-simulated crashes are expensive since they

require access to a supercomputer, and their use would

crash situations. As we expand required protections

female dummy - into Part 572, Anthropomorphic Test

Devices (49 CFR Part 572). In May 2000, the

FMVSS 208 interim final rule for advanced air bags

added the new family of crash test dummies to the test

requirements of the standard.

Developmental tests using the 5th percentile dummy

were performed by NCAP in offset frontal and full

frontal crashes in 1997 and 1998. The FY 2001 DOT

Appropriations Act prohibits the NCAP program from

including this dummy in its test results. The Research

the new child dummies are being conducted as part of

the child restraint safety program (see below).

Offset Frontal Crashes

(NASS) estimates, 42 percent of frontal crashes are

full-frontal crashes and about 56 percent are offset

frontal crashes. In September 1996, the U.S. Congress

directed NHTSA to conduct a feasibility study toward

establishing a Federal Motor Vehicle Safety Standard

safety that are not evaluated by the traditional 50

th

percentile male Hybrid III dummy.

Safety experts have noted that lower-extremity trauma

is strongly associated with disability. Currently,

neither FMVSS No. 208 nor U.S. NCAP assesses

injury risks to the lower leg. Results from NHTSA

tests in 1999 indicated that the offset test produced a

higher potential for lower leg injuries than the flat

barrier test. Research suggests that there is a safety

a frontal crash.

In the United Kingdom, the Transport and Road

Research laboratory conducted an investigation based

on real-world crashes and found that, despite the use of

seat belts, offset frontal impacts pose the greatest

threat to car occupants due to vehicle intrusion. The

U.K. study suggested that there is a need for a test in

which the barrier is offset and a deformable impact

face is used.

In response to the Congressional directive, NHTSA

Marginal, Weak, Poor).

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Australia previously studied the EU offset test

draft European test standard in 1994 and was the first

consumer crash testing program that combined both

full frontal and offset crash tests. Starting in 1999,

ANCAP aligned its test and assessment procedures

with those of Euro NCAP, using a 64.4 km/h (40 mph)

impact. ANCAP assigns a score with a maximum of

four points to each of four body regions. It modifies

the offset score based on modifiers such as excessive

rearward movement of the steering wheel, airbag

stability, steering column movement, A-pillar

and upper and lower legs.

In the U.S., beginning in 1995, the Insurance Institute

for Highway Safety (IIHS) initiated a program using a

40 percent overlap frontal-offset test to rate safety in

cars. This ongoing frontal-offset testing program

evaluates the crashworthiness of new model vehicles

crashed at 64.4 km/h (40 mph) into a deformable

barrier. The IIHS found that a full-width frontal test

and a frontal-offset test complement each other; the

Based on real world crash data and laboratory testing

of five makes and models, NHTSA’s study suggests

three changes to frontal testing could yield important

benefits. First, the lower leg instrumentation and

criteria could be incorporated into both full-frontal and

offset-frontal crash testing. Second, the offset-frontal

crash test could be used to complement the full-frontal

crash test. Third, the small stature dummy could be

used in both of the frontal crash tests to evaluate risk

to that part of the overall population.

have urged that NHTSA develop a dynamic rollover

Transportation to fund a study with the National

Academy of Sciences on whether the SSF is a

scientifically-valid measurement and to include a

comparison of the SSF test versus a test based on

dynamic driving maneuvers. The study is to be

completed in July 2001 with an agency response

within 30 days following its completion. In the

interim, the Act permits the agency to move forward

on its proposal to provide rollover rating information

to the public. The Transportation Recall