Here's why:

* Uniform acceleration means the car's velocity is changing at a constant rate.

* Acceleration is the rate of change of velocity.

* If the rate of change of velocity is constant, then the acceleration is also constant.

Example:

If a car is accelerating at a constant rate of 2 m/s², this means its velocity increases by 2 meters per second every second. This constant rate of change defines the uniform acceleration.