Using the video as a reference and some math (speed = distance/time) I get the following:

Lap 1 of video :06s - :40s = :36s || 24.8 mph
Lap 2 of video :40s - 1:12s = :32s || 27.9 mph
Lap 3 of video 1:12s - 1:47s = :35s || 25.5 mph
Lap 4 of video 1:47s - 2:16s = :29s || 30.8 mph

Average speed in video = 27.25 mph
Max speed on my computer was 34.8 mph

I'm sure the guys up front had a much higher max speed.