And they might not even stay in the lane for half of that. We clocked the entry-to-exit times of many cars at 15 seconds or less. (Bidding doesn’t necessarily start when the car enters the lane, nor does it end when the car exits. Or as CarMax explains to dealers, “You’re bidding on taillights,” Bostain said.) The 100-percent sale rate isn’t some wild anomaly. In fact, CarMax Auctions hit a 97 percent average auction sales rate in fiscal-year 2016.