Car movieclip boundry

Ok I am 16 and I am currently working on a racing car game. The only troubles i am having is with the boundry. Basically when the car touches I need it to maintain speed, but at the same time have the movieclip guide it. I am not sure how I am going to do this. Everything i have tried seems to make the car bounce off the movieclip or slide through it. Oh and its using two different variabes one for x and the other for y.

By the way, this is my first post here. SO if you do find any problems with this post please let me know.