Safe Commercial Driving Operations & Hazards practice test: free CDL General Knowledge questions

Sample Practice Questions for Safe Commercial Driving Operations & Hazards

1. Question 1Ref: AAMVA CDL Manual — Chapter 2: Safe Driving

   What should you do first when you notice your vehicle starting to skid on a wet road?

   ATake your foot off the acceleratorBApply the brakes firmlyCTurn the steering wheel sharplyDDownshift to a lower gear
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   Correct Answer
   A. Take your foot off the accelerator

   When a skid begins, your first response should be to remove your foot from the accelerator. This lets the tires regain traction naturally. Slamming the brakes or yanking the steering wheel can make the skid worse or cause you to lose control entirely.

2. Question 2Ref: AAMVA CDL Manual — Chapter 2: Adverse Conditions

   When driving in fog, what lights should you use?

   AHigh beams to cut through the fogBEmergency flashers and high beamsCLow beams or fog lights onlyDNo lights, since they reflect back
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   Correct Answer
   C. Low beams or fog lights only

   In fog, use low beams or fog lights. High beams bounce light off the water droplets in the fog and reflect it back at you, actually making visibility worse. Emergency flashers can confuse other drivers about whether you are moving or stopped, and should only be used when you are completely stopped.

3. Question 3Ref: 49 CFR 392.10 — Railroad Grade Crossings

   You are approaching a railroad crossing and the gates are starting to come down. What should you do?

   ASpeed up to cross before the gates fully lowerBPull around the gate on the shoulderCStop before the gates and wait until they riseDStop, then proceed slowly once you can see the tracks
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   Correct Answer
   C. Stop before the gates and wait until they rise

   When railroad crossing gates begin to lower, you must stop and wait until the gates fully rise and the signal stops before crossing. Never drive around lowered gates—this is both illegal and extremely dangerous. Trains travel faster than they appear and cannot stop quickly.

4. Question 4Ref: AAMVA CDL Manual — Chapter 5: Stopping Distance

   A CMV's stopping distance is affected by four main factors. Which of the following is NOT one of them?

   ATotal vehicle weightBBrake adjustmentCTire tread depthDRoad surface conditions
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   Correct Answer
   C. Tire tread depth

   While tire condition matters for overall safety, the four key stopping distance factors are perception distance, reaction distance, brake lag distance, and brake effectiveness. Weight, brake adjustment, road surface, and speed are critical. Tire tread depth is not among the four primary factors.

5. Question 5Ref: AAMVA CDL Manual — Chapter 2: Following Distance

   What is the "four-second rule" used for in CMV driving?

   AMeasuring proper following distance behind another vehicleBTiming how long you can run the engine without a breakCDetermining how long your turn signal should flashDEnsuring you check your mirrors every four seconds
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   Correct Answer
   A. Measuring proper following distance behind another vehicle

   The four-second rule helps CMV drivers maintain a safe following distance. Pick a fixed point ahead; if you pass it less than four seconds after the vehicle in front of you, you are following too closely. Add more time for wet or icy roads.