There has been considerable investigation into vehicle bumper response in low speed accidents. A bumper to bumper collision often results in very little or no apparent damage even though the collision might have been significant. However, when two vehicles which have considerably different bumper heights collide, the resulting damage quite often is visually extensive but it is confined to relatively weak sheet metal, lighting, and/or grill components. The amount of research dedicated to bumper override in low speed impacts is much more limited.
In an effort to add to the base of knowledge relative to low speed bumper override impacts, the authors conducted a series of barrier impacts involving several vehicles with human occupants. The impacts were in the 3 to 8 km/hr range. The vehicles were instrumented with an accelerometer and a velocity sensor. The occupants were instrumented with 8 accelerometers. For comparison, each vehicle (with occupant) was first impacted into the barrier with normal bumper contact. Then an override fixture was attached to the barrier, and other impacts were performed while maintaining all other conditions as identical as possible.
Comparison of occupant accelerations for barrier versus override impacts at similar speeds is presented. Photographs of test damage as presented may be useful in estimating speed change and/or accelerations of other vehicles involved in actual accidental collisions.