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CDL General Knowledge Test · CDL General Knowledge Test

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CDL General Knowledge Test Night, Fog, Winter, and Hot Weather Summary

Importance
★★★★☆ (4 / 5)
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About 5 of 50 CDL General Knowledge Test questions (10%)

Night vision and glare, headlight use, fog, winter checks and slippery roads, wet brakes, and tire, coolant, and radiator cap safety in very hot weather.

📖 See Night, Fog, Winter, and Hot Weather concepts →

Night, Fog, Winter, and Hot Weather: must-know points

  • Dim your high beams within 500 feet of an oncoming vehicle or a vehicle you are following.
  • In fog, use low beams and fog lights, slow down before you enter it, and avoid passing.
  • Do not let air out of hot tires. Pressure goes up with heat and drops when the tire cools.
  • Never remove the radiator cap until the system has cooled.

Night, Fog, Winter, and Hot Weather: 7 sample questions

Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 1. When should you dim your high beams?

  1. ① Within 200 feet of an oncoming vehicle
  2. ② Only when the other driver flashes their lights
  3. ③ Within 500 feet of an oncoming vehicle, and when following a vehicle within 500 feet
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Answer: ③ Within 500 feet of an oncoming vehicle, and when following a vehicle within 500 feet

Key point: Dim lights within 500 feet

Dim your lights within 500 feet of an oncoming vehicle and when following another vehicle within 500 feet. Use high beams when it is safe and legal.

Wrong choices

  • Within 200 feet of an oncoming vehicle: 200 feet is too late. The other driver is already blinded.
  • Only when the other driver flashes their lights: You must dim even if they do not flash.
Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 2. If you must drive in fog, which lights should you use?

  1. ① Low-beam headlights and fog lights
  2. ② High-beam headlights
  3. ③ Parking lights only
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Answer: ① Low-beam headlights and fog lights

Key point: Fog: low beams and fog lights

The best advice for fog is to pull off and wait. If you must drive, slow down before you enter the fog, use low beams and fog lights even in daytime, turn on your four-way flashers, and avoid passing.

Wrong choices

  • High-beam headlights: High beams reflect off the fog and make it harder to see.
  • Parking lights only: Parking lights make you hard for others to see.
Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 3. On a very hot day, your tire pressure reads higher than normal. What should you do?

  1. ① Let some air out to bring it back to normal
  2. ② Do not let air out. The pressure will drop when the tire cools.
  3. ③ Drive faster so air flow cools the tires
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Answer: ② Do not let air out. The pressure will drop when the tire cools.

Key point: Never let air out of hot tires

Air pressure rises with temperature. Do not let air out, or the pressure will be too low when the tire cools. If a tire is too hot to touch, stay stopped until it cools, or it may blow out or catch fire.

Wrong choices

  • Let some air out to bring it back to normal: Then the tire will be under-inflated once it cools.
  • Drive faster so air flow cools the tires: Higher speed makes tires hotter.
Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 4. When is it safe to remove the radiator cap?

  1. ① Any time the engine is not overheated
  2. ② Any time, as long as you wear gloves
  3. ③ Only after the cooling system has cooled down
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Answer: ③ Only after the cooling system has cooled down

Key point: Open the radiator cap only when cool

Never remove the radiator cap until the system has cooled. Steam and boiling water can spray under pressure and cause severe burns. If you can touch the cap with your bare hand, it is probably cool enough.

Wrong choices

  • Any time the engine is not overheated: A hot system is under pressure even if it is not overheating.
  • Any time, as long as you wear gloves: Gloves do not protect you from a spray of boiling coolant.
Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 5. What is black ice?

  1. ① A thin layer of clear ice that makes the road look only wet
  2. ② Thick, dark ice that is easy to see
  3. ③ Ice that forms only on gravel roads
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Answer: ① A thin layer of clear ice that makes the road look only wet

Key point: Black ice looks like a wet road

Black ice is a thin layer clear enough to see the road through. It makes the road look wet. Any time the temperature is below freezing and the road looks wet, watch out for black ice.

Wrong choices

  • Thick, dark ice that is easy to see: Black ice is hard to see. That is why it is dangerous.
  • Ice that forms only on gravel roads: It can form on any road surface.
Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 6. You have just driven through deep standing water. What should you do with your brakes?

  1. ① Brake as hard as you can right away to test them
  2. ② Keep light pressure on the brakes for a short distance to dry them, then make a test stop
  3. ③ Nothing. Brakes dry out on their own in seconds
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Answer: ② Keep light pressure on the brakes for a short distance to dry them, then make a test stop

Key point: Wet brakes: light pressure, then test stop

Water can make brakes weak, uneven, or grabby. After going through water:

  1. Keep light pressure on the brakes for a short distance to heat and dry them.
  2. Make a test stop when it is safe (check that no one is behind you).
  3. If they still do not work well, dry them more the same way.

Wrong choices

  • Brake as hard as you can right away to test them: Hard braking with wet brakes can cause lockups or pulling.
  • Nothing. Brakes dry out on their own in seconds: Wet brakes can be weak or grab. You need to dry them.
Practice questionReviewedCDL General Knowledge Test › Night, Fog, Winter, and Hot Weather★★★★☆

Question 7. In very hot weather, how often should you inspect your tires?

  1. ① Every 4 hours or every 200 miles
  2. ② Only at the end of the day
  3. ③ Every 2 hours or every 100 miles
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Answer: ③ Every 2 hours or every 100 miles

Key point: Hot weather: tires every 2 hours or 100 miles

Heat raises tire pressure and the risk of blowouts and fires. In very hot weather, inspect the tires every two hours or every 100 miles.

Wrong choices

  • Every 4 hours or every 200 miles: This is too long between checks in very hot weather.
  • Only at the end of the day: Heat can damage tires during the trip.

Test yourself.

Night, Fog, Winter, and Hot Weather: 5 questions →CDL General Knowledge Test: 5 questions →