When is the average velocity equal to the instantaneous velocity

Average velocity is equal to the instantaneous velocity when acceleration is zero. In order for acceleration of an object to equal zero, there can be no change in speed or direction. For example, when a car is traveling down a straight road on flat land using cruise control.

Average velocity = the distance traveled divided by the amount of time it took to travel that distance.

Instantaneous velocity = the velocity at a particular instant of time.