Here's why:

* Velocity is a measure of both speed and direction.

* Uniform velocity means the speed and direction of the vehicle remain constant.

* Acceleration is the rate of change of velocity. If the velocity isn't changing, there's no acceleration.

Think of it this way: If you're driving on a straight road at a constant 60 mph, you're moving with uniform velocity. Even though you're in motion, your acceleration is zero because you're not speeding up or slowing down.