Fast Tracks is a racing game released in 1985 for the Commodore 64. It was designed by Mark Turmell and published by Activision.
The game involves running into other cars on the track. Each time a player bumps another car off the track, the car returns to the start of the lap, and two seconds are removed from the final time. Of course, if you leave the track you also have to restart the lap.
A map editor is also available in the game, which can be saved onto the disc
Source: Wikipedia, "Fast Tracks: The Computer Slot Car Construction Kit," available under the CC-BY-SA License.