From McHenry Accident Reconstruction:
- "Confusion in the interpretation of damage in actual accidents can be created by the use of the term Barrier Equivalent Velocity as opposed to Barrier Impact Velocity in the specification of corresponding test conditions. Such confusion comes from the following definition (e.g., Reference ) of the Barrier Equivalent Velocity (BEV):
- BEV is “the equivalent impact velocity of a vehicle into a fixed, rigid barrier that would result in the same magnitude of crush as observed on a subject vehicle under analysis.”
Note that this confusion could be overcome by either
- (a) the definition of deployment thresholds in terms of Barrier Impact Velocity rather than BEV, or
- (b) a more proper definition of BEV as meaning “that portion of the impact speed-change that precedes the achievement of a common velocity.”
- When the two vehicles involved in a car-to-car collision have essentially similar deformation and weight characteristics, such a BEV method of assessing impact severity can be reasonably reliable for use in statistical studies. However, if the vehicles have dissimilar characteristics, the BEV ratings can be considerably in error as a measure of impact severity.
- For example, if a heavy soft car collides with a light stiff car, it is possible for the stiffer car to experience a substantial change in velocity with no appreciable damage (Ref. , ).
- 1. Kerkhoff, J.F., Husher, S.E., et al, “ An Investigation into Vehicle Frontal Impact Stiffness, BEV and Repeated Testing for Reconstruction”, Society of Automotive Engineers Paper No. 930899.
2. Ashton, S.J., Hardy, J.L.G., Mackay, G.M., “The Use of the Vehicle Deformation Index and Collision Speed Assessments”, Proceedings of the International Accident Investigation Workshop, Pilot Study on Road Safety, NATO, Brussels, Belgium, June 28-29, 1973.
3. Hight, P.V., Lent-Koop, D.B., Hight, R.A., “Barrier Equivalent Velocity, Delta-V, and CRASH3 Stiffness in Automobile Collisions”, Society of Automotive Engineers Paper No. 850437.
4 Knipling, R.R., Kurke, D.S., “NASS Field Techniques – Volume IV – CRASH MEASUREMENTS”, US Department of Transportation, National Accident Sampling System,
(NOTE: lAug 2022 link was to NHTSA site, no longer valid, will post up full report soon)