Rear-end collision

A rear-end collision in Yate, near Bristol, England, in July 2004. The car failed to stop when the semi-trailer stopped at a roundabout. The car's hood can be seen deep under the rear of the lorry. There were no injuries.

A rear-end collision (often called simply rear-end) is a traffic accident where a vehicle (usually an automobile or a truck) impacts the vehicle in front of it, so called because it thus hits its rear. It may also be a rail accident where a train runs into the rear of a preceding train.

Typical scenarios for rear-ends are i) a sudden deceleration by the first car (for example, to avoid someone crossing the street), ii) the following car that does not have the time to brake and impacts the first and iii) at a road junction the following car accelerates more rapidly than the leading.

In rear-ends, mechanical damage is equally shared by the two vehicles if they have identical plasticity and mass. Injuries to the occupants are usually much worse for the impacted vehicle, because occupants of the following vehicle often anticipate the imminent impact and take automatic measures.

As a rule of thumb, impacting into another car is equivalent to impacting into a rigid surface (like a wall) at half of the speed. This means that rear-ending a still car while going at 30 mph is equivalent, in terms of forces, to impacting a wall at 15 mph. The same is true for the impacted vehicle.

A typical medical consequence of rear-ends, even in case of collisions at moderate speed, is Whiplash.

For purposes of insurance and policing, the driver of the car that rear-ends the other car is almost always considered to be at fault due to not being within stopping distance or lack of attention.

The Ford Pinto became the focus of a major scandal when it was alleged that a flaw in its design could cause fuel-fed fires as the result of a rear-end collision, though the car was actually no more likely to cause such fires than similar models sold at the time.