Question

The motion of a car on a position time graph is represent with a horizontal line . What does this indicate about the cars motion

Answer 1

It indicates that car is at rest at all time (t) :-) Hope it helped you. ✌

Answer 2

A horizontal line on a position/time graph means that the car's position
doesn't change as time goes by.  This is a pretty good indication that
the car is either stopped at a red light, or else parked in the driveway. 
It isn't moving.