I was racing and noticed a car come to a complete (instant) stop on the track.
if you follow Ozzy (on lap 3, straight) in this replay you will see what i am talking about.

What causes this to happen? I've never had it happen to me before.

If you ask me it´s clearly lag. This could easily happen to you too, if you do this with a driver who lags or if you lag yourself. No bug, just lag.

Quote from mhartma5 :

I was racing and noticed a car come to a complete (instant) stop on the track.
if you follow Ozzy (on lap 3, straight) in this replay you will see what i am talking about.

What causes this to happen? I've never had it happen to me before.

The guy in front of him brakes and lag does the rest. Pretty common. Might want to report the other guy for wrecking if you know the admins.

thanks for the replies guys, i never seen this before and thought, maybe, someone was cheating. Good to know its just lag.