What is the function of a Bumper in an automobile?

A bumper is a kind of structure attached in the front and rear of an automobile to absorb impact in a minor collision, ideally minimizing repair costs. Bunpers are standard equipments that are commonly used in vehicles nowadays.

Bumpers also have two major safety functions: diminishing height mismatches between vehicles, and safeguarding pedestrians from major injury.

The bumper structure on modern automobiles usually have a plastic cover over a reinforcement bar made up of steel, aluminum, fiberglass composite, or plastic.

Bumpers save other vehicle components by dissipating the impact of kinetic energy generated in a collision. This energy is a function of vehicle mass and velocity squared. In formula form, it is given by  which suggests that a vehicle protecting the components at 5 km/ hr must be four times stronger than the bumper that protects at a 2.5 km/hr.