Usually there is a judged section that you choose on track you choose, and you can either have a follow car who is judging, people spectating or judges placed like clipping points on each corner.
One chase run, one lead run. The judge can call for a OMT (one more time, re run) if the battle is close and he can't decide the winner.
A good judge bases his decision on entries, angle, speed, line and how clean your driving is, (transitions, how close you can chase, how much of a gap you create as a leader etc.)
When contact is made: If the follower makes contact with the leader resulting in a spin or crash, the leader gets the win. If the leader spins out or does a mistake resulting in a crash, the chaser wins. The judge can also call for a re-run if he wants to. BUT, trading paint is cool, so don't be afraid to stay close to the leader.
-Get it right dawg, we ain't ever left-
-We just, moved in silence and repped to the death-
-It's official, I survived what I've been through-
Y'all got drama "the saga continues"-