Why should drivers be cautious when passing a bicyclist at higher speeds?

• Motor vehicles create strong wind currents that can batter or cause an accident for the bicyclist.
  Explanation:

  "Be aware that when traveling at higher speeds, motor vehicles create strong wind currents which can batter a person on a bicycle, even resulting in an accident."
• Bicyclists can speed up unexpectedly.
• Bicyclists always have the right of way.
• There is no need to be cautious when passing a bicyclist.