asked my son who is a track guy and he said when bolt said his world record in the 100m he was clocked at just under 28 mph at roughly 60m in the race
yes, that is a fairly big margin over derius, but then consider bolt was running in a straight line, custom built shoes for maximum traction, wearing a one piece that weighs damn near nothing, out of starting blocks, and on a track that is designed for maximum traction and rebound
derius is wearing full uniform, football cleats, carrying a ball, having to make a turn, and running on a turf field and that speed is just ridiculous