Skip to content

Controlling Speed

Controlling Speed is a required knowledge area under 49 CFR 383.111(a)(9) (the effects of speed on stopping distance, surface conditions, road shape, visibility, and traffic flow). The general duty to reduce speed, and stop if needed, in hazardous conditions is directly codified at 49 CFR 392.14.

Practice Controlling Speed

5 Questions

  1. Why do empty trucks require greater stopping distances than fully loaded trucks, even though they weigh less?
  2. Under 49 CFR 392.14, what must a driver do when snow, ice, or heavy rain reduces the traction between the tires and the road?
  3. Why can a loaded truck roll over on a curve even while traveling at or below the speed posted on a curve warning sign?
  4. Under 49 CFR 392.14, what must a driver do when fog reduces visibility of the road ahead?
  5. Why does driving significantly faster than the surrounding flow of traffic increase crash risk, even if the speed itself is within the legal limit?