Toward quieter, less cluttered marathons

No marathoner should have to dodge police motorcycles near the finish, or be subjected to gas fumes and blaring sirens mile after mile. These hazards, though, are not unknown to anyone who's ever led the Boston Marathon, and possibly other similar races. To cut down on noise, congestion, and exhaust en route, why not replace motorcyles with moped escorts, use bullhorns for crowd clearance only when necessary, and find some sort of electric alternatives to the official buses and truck that litter the course? If marathons are going commercial, some manufacturer would probably jump at the chance to put a non-combustion-powered vehicle on display.