Project: Compatability of Cars in Crashes

Reference: S095B/VF

Last update: 27/08/2003 15:15:59


The project objectives are:

* the development of new standards and test procedures that are designed to improve the compatibility of car structures in car-to-car impacts thus enhancing the level of occupant protection in frontal and lateral impacts giving due consideration to protection in impacts with pedestrians, HGVs and other obstacles; and
* complete the development of frontal impact test procedures for the protection of car occupants.


Following the introduction of regulatory tests for frontal and side impacts, studies have shown that improving the compatibility of cars could deliver a one third reduction in the number of fatal and serious injuries sustained in car-to-car impacts. This project was therefore commissioned to identify and understand the factors which influence compatibility in car-to-car frontal and side impacts, and to propose test methods that could be used to measure and control the compatibility of cars.

The report concludes that whilst sufficient knowledge has been gained to propose concepts for testing compatibility in frontal impacts, further research will be needed if test methods are to be proposed for side impact compatibility. For good compatibility in frontal impacts, car structures need to interact in a predictable manner to absorb energy with minimal occupant compartment intrusion. This requires car fronts to have a more uniform stiffness distribution which is matched to that of other cars. For side impact compatibility neither mass nor stiffness are seen to have a major effect.

Three test methods are recommended for further consideration - a 64km/h 40% offset and a 56km/h full frontal test into a deformable barrier mounted on a high resolution load cell wall, and a high speed 40% offset into a deformable barrier. The test conditions, performance criteria and limit values are to be developed in a new project which will provide the UK contribution to EU and UN work on future regulatory tests.


TRL Limited
Crowthorne House, Nine Mile Ride, Wokingham, Berkshire, RG40 3GA
+44 (0)1344 773131

Contract details

Cost to the Department: £2,979,000.00

Actual start date: 24 April 1995

Actual completion date: 31 July 1999


PR/SE/563/99. Compatibility and Frontal Impact Test Procedures
Author: TRL Ltd.
Publication date: 01/07/1999
Source: Contact

Conference papers presented to ESV 1998
Author: TRL Ltd.
Publication date: 01/05/1998
Source: Contact

RO-97-SC 1064. Improvement of Crash Compatibility Between Cars. Report for the European Commission DGVII
Author: Consortium Partners
Publication date: 30/04/1999
Source: Contact:

Summary of results

  1. Much has been learnt about frontal compatibility and three tests were proposed for scientific consideration by EEVC and IHRA. Side impact is still exploratory but is not adversely affected by potential frontal improvements. The international research community is now well engaged on what is a longer term effort. Benefit estimates were limited and drew on Renault work.
    Focus has been on car to car impacts. Specific consideration has not been given to HGVs or pedestrians but improved compatibility measures need not inhibit progress on these fronts.