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.
This Trailer was done by LunaG from Headshot. It is a demonstration of what he is able to do. He is working right now on a release trailer for V1.4