CO-WORKER WAS TRAVELING ON THE ROADWAY & SAW #15 TRUCK SITTING IN A WATER POCKET, ABOUT 15' IN THE WATER, WEST OF THE ROADWAY. ANOTHER CO-WORKER NOTICED THE TRUCK WAS STILL RUNNING. AS HE BAC KED UP HE SAW SOMEONE SLUMPED OVER ON THE FRONT SEAT. HE CHECKED FOR PULSE & THERE WAS NONE. CPR WAS STARTED. IT IS BELIEVED HE STOPPED & TRIED TO PUT TRUCK IN PARK. FATAL HEART ATTACK.