Start Free Practice

CDL Test: Weather and night questions and answers

Every question we use, with the correct answer, an explanation and the source it comes from.

Take a practice test 16 questions · Why trust us

Weather and night

16 questions

  1. #1

    If you must drive in fog, which should you turn on so vehicles approaching from behind notice you sooner?

    1. Your high beams
    2. Your cruise control
    3. Your 4-way flashers
    4. Your interior light

    Answer: C. Turning on 4-way flashers gives vehicles approaching from behind a quicker chance to notice you.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 52Turn on your 4-way flashers.

  2. #2

    When approaching fog on the highway, you should:

    1. assume the fog will thin out once you are inside
    2. keep your speed because fog thins quickly
    3. speed up to leave the fog sooner
    4. not assume the fog will thin out after you enter it

    Answer: D. Visibility can deteriorate rapidly, so slow down before entering fog.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 52Do not assume that the fog will thin out after you enter it.

  3. #3

    What is the minimum tread depth required in every major groove of front tires?

    1. 2/32 inch
    2. 6/32 inch
    3. 4/32 inch
    4. 8/32 inch

    Answer: C. You must have at least 4/32 inch tread depth in every major groove on front tires.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53You must have at least 4/32 inch tread depth in every major groove on front tires and at least 2/32 inch on other tires.

  4. #4

    What is the minimum tread depth required on tires other than the front tires?

    1. 1/32 inch
    2. 2/32 inch
    3. 4/32 inch
    4. 6/32 inch

    Answer: B. Tires other than the front tires need at least 2/32 inch of tread in every major groove.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53You must have at least 4/32 inch tread depth in every major groove on front tires and at least 2/32 inch on other tires.

  5. #5

    In winter driving, a lack of spray from other vehicles' tires indicates that:

    1. the road is dry and safe
    2. the road is flooded
    3. ice has formed on the road
    4. the temperature is rising

    Answer: C. A lack of spray from other vehicles indicates ice has formed on the road.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53A lack of spray from other vehicles indicates ice has formed on the road.

  6. #6

    As the temperature rises to the point where ice begins to melt, the road becomes:

    1. less slippery, so you can speed up
    2. even more slippery, so slow down more
    3. safe to drive at normal speed
    4. slippery only on bridges

    Answer: B. As ice begins to melt the road becomes even more slippery; slow down more.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53as the temperature rises to the point where ice begins to melt, the road becomes even more slippery.

  7. #7

    Exhaust leaks can let poisonous carbon monoxide into the cab. Carbon monoxide gas will cause you to:

    1. become sleepy
    2. become more alert
    3. lose hearing
    4. smell fuel strongly

    Answer: A. Carbon monoxide will make you sleepy and in large enough amounts can kill you.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53Carbon monoxide gas will cause you to be sleepy.

  8. #8

    Wet brakes from heavy rain or deep standing water can cause:

    1. stronger braking and shorter stops
    2. weak, uneven or grabbing brakes
    3. brakes that never need adjustment
    4. faster brake lining wear only

    Answer: B. Water in the brakes can cause weak braking, uneven application, grabbing, wheel lockups and pulling to one side.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53Water in the brakes can cause the brakes to be weak, to apply unevenly, or to grab.

  9. #9

    In very hot weather the tire air pressure rises. If the tires are hot, you should:

    1. let air out until pressure is normal
    2. add air to balance the heat
    3. drive faster to cool them
    4. not let air out of the tires

    Answer: D. Air pressure increases with temperature, so do not let air out or the pressure will be too low when the tires cool.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 53Do not let air out or the pressure will be too low when the tires cool off.

  10. #10

    In very hot weather, spots where tar "bleeds" to the surface of the pavement are:

    1. extra grippy
    2. very slippery
    3. safe at any speed
    4. dangerous only for cars

    Answer: B. Tar in the pavement frequently rises to the surface in very hot weather, and those spots are very slippery.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 54Spots where tar “bleeds” to the surface are very slippery.

  11. #11

    In hot weather, the coolant temperature gauge goes above the highest safe temperature. You should:

    1. keep driving until the next scheduled stop and then check the gauge
    2. open the radiator cap right away to let the pressure escape
    3. drive faster to increase airflow through the radiator and cool the engine
    4. stop driving as soon as safely possible and find out what is wrong

    Answer: D. If the gauge goes above the highest safe temperature, engine failure and possibly fire could follow.

    Source: North Dakota CDL Manual (AAMVA model), Section 2, p. 54Stop driving as soon as safely possible and try to find out what is wrong.

  12. #12

    The CDL manual's best advice for driving in fog is to:

    1. Turn on your high beams
    2. Follow the taillights ahead closely
    3. Pull off the road until it clears
    4. Speed up to get through it quickly

    Answer: C. The best advice is not to drive in fog: pull off into a rest area or truck stop until it clears. If you must drive, slow down, use low beams and fog lights, and turn on your 4-way flashers.

    Source: Michigan CDL Manual (2022), 2.12

  13. #13

    On slippery roads, the engine brake or speed retarder should be:

    1. Used constantly
    2. Turned off — it can make the drive wheels skid
    3. Used only downhill
    4. Set to maximum

    Answer: B. On slippery surfaces engine brakes and retarders can cause drive-wheel skids.

    Source: Michigan CDL Manual (2022), 2.13

  14. #14

    In very hot weather, you should check tire mounting and air pressure about every:

    1. 10 miles
    2. Day
    3. 500 miles
    4. Two hours or 100 miles

    Answer: D. Check every two hours or 100 miles; never let air out of hot tires.

    Source: Michigan CDL Manual (2022), 2.14

  15. #15

    When should you remove the radiator cap?

    1. Only after the cooling system has cooled
    2. While the engine is hot, to check the level
    3. Whenever the gauge is in the red
    4. Never — it is sealed

    Answer: A. Never open the pressurized cooling system until it has cooled.

    Source: Michigan CDL Manual (2022), 2.14

  16. #16

    After driving through deep water, to dry your brakes you should:

    1. Brake hard several times at speed
    2. Park and wait for an hour
    3. Slow down, use a low gear and apply light brake pressure
    4. Pump the clutch

    Answer: C. Water can make brakes weak, uneven or grabbing; light pressure in low gear dries them.

    Source: Michigan CDL Manual (2022), 2.13
Take a practice test