Well if your car has raytraced reflections and the scene prop has those too, then your render will be dog slow, no matter how powerfull you computer might be. Lower the bucket size (as low as 12 perhaps) and think hard if you need every element in the scene to be visible in raytracing. Allso lower your raytrace bounces to 2. Lot's of reflections ---> slow render.

-Morbo will now introduce the candidates - Puny Human Number One, Puny Human Number Two, and Morbo's good friend Richard Nixon.
-Life can be hilariously cruel