What is a car rally

Car rally :

In a street rally, contenders contend over a foreordained course with time as the opponent. Vehicles start at (normally) one-minute interims. There is no immediate no holds barred dashing, and nowadays the accentuation is particularly on route and cooperation instead of absolute speed.

They run with time as the opponent, each vehicle in turn, on earth, asphalt, and anything in the middle. They run in all climate, in for all intents and purposes each nation on the planet. The game is a brilliant, beautiful thing, all commotion, and brutality and sliding sideways between trees at 100 mph.

The easiest answer is that Rally is each vehicle in turn on an open street shut down for hustling, and Rallycross is numerous autos running together on a shut course explicitly intended for dashing.