What are those little RC cars called that run on a set track that you snap together?

My niece wants to play her real-life one, but i can't find any of the cars for it. She likes to play little computer games so i thought i could find a flash game i remembered playing a few years ago with those games, if anybody knows the name of that game, or a link that would be great but i could google for it myself if i knew what those little racing car games were actually called.

I always find and play online flash games at http://www.wowflashgames.com

It's free and updated regulary.

Enjoy it