Without going under the "Dial-In" E.T.
Example. Say your Mustang runs 13.50's consistently (it's a nice even #). You get lined up against a serious drag car that runs the 1/4 in 8.50 seconds. If you use those #'s for each car's dial-in (respectivly). The tree turns green for you 5 seconds before the drag car. If you both run your dial-in, then reaction time will win the race. It keeps it fair for different speed cars. If you run a 13.49 second run and beat the faster car to the traps, you loose the race because you "broke-out" (effectivly lied about how fast your car was). If you run slower 13.55 seconds, but still get to the traps first, you win.