These numbers are a little off. Most commuters are going to scoot along in the 8-12 mph range. People riding for exercise or training for a sport are going to get up near 20 mph. Amateur bike races will hold sustained speeds of 24-30 mph for a few hours (depending on the terrain). In the TdF this year the fastest team in the time trial averaged 35 mph for 25 min. TdF sprinters can hit 50 mph and 70 mph on mountain descents.