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Winter Driving

Winter Driving is a required knowledge area under 49 CFR 383.111(a)(12)(i), which names snow, ice, sleet, and high wind directly. The tire tread depth figures tested here, 4/32 inch on front wheels and 2/32 inch on all others, are directly codified at 49 CFR 393.75(b) and (c).

Practice Winter Driving

5 Questions

  1. Under 49 CFR 393.75, what is the minimum tread depth required in a major tread groove of a commercial motor vehicle's front (steering) tires, and how does that compare to its other tires?
  2. Under 49 CFR 383.111(a)(12)(i), which weather conditions does federal regulation specifically name as examples of the "bad weather" a CDL knowledge test must cover?
  3. Why does guidance for driving on icy or snow-covered roads advise against using the engine brake or speed retarder?
  4. Which of the following is a clue that a road surface may be icy even though it does not look wet or icy?
  5. After driving a commercial motor vehicle through a deep puddle or standing water, why does guidance recommend applying light, steady pressure to the brakes for a short distance afterward?