From one of the newspaper articles:

Dan Seeman, who works on Clanton and was headed to a nearby hardware store, said he saw the collision. The bicyclist was a big guy, he said, and had gotten his attention.

"One moment he was alive and riding by me," Seeman said, "and the next he was dead."

Seeman said the man on the bicycle was riding fast and seemed to have his head down. The bike hit the bus near the door.

The bus driver couldn't get his front door open, Seeman said, and exited from a back one. The driver checked on the bicyclist, told Seeman to call 911, then ran for help.

It opens many possibilities on BOTH sides. IF (Big if, a decent road bike position might look like head down) he had his head down then the rider may have ridden into the side of the bus when he had very adequate time to stop. Other side is he may have been going fast, the driver saw him and assumed he had plenty of time to complete the turn. One last thing, it is VERY rare to see riders really flying at the extreem right where they can get 'lost' in the parked cars. So this is one big point on the side that he should have been seen.