Q3Rally is a car driving and car combat standalone game. It is based on Ioquake3. Since the latest release (available at 20/08/18) also MacOS X (10.5 and above) is supported. Also Windows and Linux (x86/x64). Try it out. It's damn fast, baby.
It is all i could find at the Internet. Many mapmodels. Useful for Q3Rally but also for all Q3 Level Designer.