DRIVING VEHICLE, COMING TO TOLL BOOTH 300 FT AWAY; GRAYISH SMOKE CAME FROM UNDER HOOD. OTHER PEOPLE NOTICED HEAVY BLACK SMOKE. TOLL OFFICIAL CALLED FIRE DEPT; VEHICLE IN FLAMES BEFORE FIRE DEPT ARRIVED; WAS TOWED TO YARD. INS. CO. WILL LOOK AT VEHICLE IF MOVED TO DEALER. *AK POSSIBLE ENGINE FAILURE. *SLC