When you use your car to film shots it makes the scene more real and looks as though you are walking or running with that person in the shot. You can also create out of body shots along with out of body shots you can create more depth by standing on top of the car to create a birds eye view.
You may also have problems with your audio because of the running engine but an easy fix is to put your car into neutral and push it along yourself.
Using your car can be very beneficial to compose a movie with unique shots that capture the audiences attention.
http://nofilmschool.com/2015/09/tutorial-your-car-best-friend-capturing-smooth-tracking-shots