Walkies!

The gold car has a very impatient dog in it. Slide the traffic out of the way — cars only move along their lane — and drive him out the exit.

Every puzzle here has been checked by a solver, so the par is a real number rather than a guess — if you beat it, you found the intended line. The car that unlocks a board is rarely the one blocking the exit; it is usually two moves upstream, holding the car that holds the car. Work backwards from the gold one.