CDL general knowledge practice test 1

1. How does ABS primarily assist the driver during braking?

1. It helps avoid wheel lock up and maintain control.
2. It guarantees a shorter stopping distance on all surfaces.
3. It prevents skids caused by spinning drive wheels.
4. It replaces the need for regular brake maintenance.

2. What is the primary reason a bridge formula sets lower maximum axle weights for axles that are closer together?

1. To prevent overloading bridges and roadways
2. To improve fuel efficiency on long hauls
3. To allow for faster acceleration on upgrades
4. To reduce the wear on tire treads

3. What is the recommended action to regain control when a vehicle is hydroplaning?

1. Apply the brakes firmly to stop the vehicle quickly.
2. Steer sharply in the direction of the skid.
3. Release the accelerator and push in the clutch.
4. Increase speed to break through the water layer.

4. When driving down a long, steep grade in a modern truck, why might a driver need to use a lower gear than they would use to climb the same hill?

1. Modern trucks have less friction and air drag to hold them back going down hills.
2. Modern trucks have heavier engines that require lower gears for stability.
3. Modern trucks have automatic transmissions that cannot shift at high speeds.
4. Modern trucks have shorter wheelbases that require lower gears for turning.

5. According to the handbook, what is the primary function of an Antilock Braking System (ABS) during hard braking?

1. It significantly shortens the stopping distance compared to normal brakes.
2. It keeps the wheels from locking up to help maintain vehicle control.
3. It increases the overall braking capability of the vehicle beyond normal limits.
4. It automatically applies the brakes when the driver does not respond quickly enough.

6. When driving in heavy traffic, what is the recommended speed strategy for a commercial driver?

1. Drive at the speed of other vehicles
2. Drive faster than other vehicles to save time
3. Drive at the maximum posted speed limit regardless of traffic
4. Drive slower than other vehicles to ensure extra stopping distance

7. What action should a driver take if they are unsure whether their vehicle has sufficient overhead clearance to pass under an object?

1. Accelerate quickly to minimize time under the object.
2. Take another route.
3. Stop immediately in the middle of the lane.
4. Assume the posted height is accurate and proceed.

8. Why is braking inside a curve considered dangerous for commercial drivers?

1. It causes the engine to overheat.
2. It makes it easier to lock the wheels and cause a skid.
3. It forces the vehicle to roll over immediately.
4. It prevents the driver from seeing the exit of the curve.

9. Which type of trailer is specifically identified in the handbook as being prone to getting stuck on raised railroad crossings?

1. Low slung units such as lowboys or car carriers.
2. Standard dry van trailers with tandem axles.
3. Tank trailers carrying liquid hazardous materials.
4. Flatbed trailers carrying oversized loads.

10. According to the handbook, when must a driver re-check cargo and securing devices after beginning a trip?

1. Within the first 50 miles
2. Only if the weather is bad
3. Every 100 miles regardless of breaks
4. Only before entering a highway

11. When operating a vehicle with a manual transmission and starting from a stop, what is the correct procedure to prevent rolling back?

1. Fully engage the clutch before releasing the brake.
2. Partly engage the clutch before taking your right foot off the brake.
3. Release the parking brake immediately after taking your foot off the brake.
4. Apply the hand valve on the trailer brake before engaging the clutch.

12. Why is it important to check your mirrors before starting a lane change?

1. To ensure the trailer is straight
2. To make sure there is enough room
3. To check for tire fires
4. To verify the cargo is secure

13. According to the handbook, what is the correct procedure for using mirrors while driving?

1. Focus on the mirrors for an extended period to ensure a complete view of the surroundings.
2. Check them quickly and look back and forth between the mirrors and the road ahead.
3. Rely solely on convex mirrors because they provide a wider field of vision without distortion.
4. Avoid checking mirrors frequently to maintain focus on the road directly in front.

14. Why do empty trucks require greater stopping distances compared to fully loaded trucks?

1. Empty trucks have heavier brakes that take longer to engage.
2. Empty vehicles have less traction, causing them to bounce and lock up their wheels.
3. Fully loaded trucks have more air resistance, which helps slow them down.
4. Empty trucks have shorter reaction times for the driver.

15. If hydraulic pressure is lost, how should a driver use the parking brake to slow the vehicle?

1. Apply it fully and hold it until the vehicle stops.
2. Press the release button or pull the release lever at the same time you use the emergency brake.
3. Apply it only when the vehicle is already stopped.
4. Use it exclusively on uphill grades to prevent rolling backward.

16. What is the minimum tread depth required for tires other than the front tires?

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

17. What is the minimum number of tie-downs required for securing cargo, regardless of the cargo's size?

1. One tie-down per ten feet of cargo.
2. Two tie-downs.
3. Three tie-downs.
4. One tie-down per five feet of cargo.

18. What is the required shape and orientation for hazardous materials placards?

1. Square, lying flat.
2. Rectangular, oriented horizontally.
3. Diamond shape, turned upright on a point.
4. Circular, centered on the panel.

19. How does doubling your speed affect the stopping distance of your vehicle?

1. It doubles the stopping distance.
2. It increases the stopping distance by about four times.
3. It has no significant effect on stopping distance.
4. It halves the stopping distance due to increased momentum.

20. How does stopping distance change if a driver doubles their speed?

1. It increases by four times
2. It increases by two times
3. It remains unchanged
4. It decreases by half

21. When a tire fails, what is the recommended procedure regarding the brake pedal?

1. Apply the brakes firmly and immediately to stop the vehicle as quickly as possible.
2. Stay off the brake until the vehicle has slowed down, then brake very gently.
3. Pump the brakes rapidly to prevent the wheels from locking up.
4. Use the parking brake to stabilize the vehicle while steering with one hand.

22. What is the recommended action for handling a cargo fire in a van or box trailer?

1. Open the doors immediately to allow heat to escape.
2. Keep the doors shut to limit oxygen supply to the fire.
3. Use water directly on the flames to cool the cargo.
4. Remove the cargo from the trailer before extinguishing.

23. If ABS is present only on the tractor, what should the driver do if the trailer begins to swing out?

1. Let up on the brakes if safe to do so.
2. Apply harder brakes to stabilize the tractor.
3. Steer sharply in the opposite direction.
4. Ignore the swing and continue braking firmly.

24. According to the proper braking technique for long or steep downgrades, at what speed should a driver release the brakes after applying them?

1. When the speed has been reduced to approximately five mph below the safe speed.
2. When the speed has increased to the safe speed.
3. Immediately after applying the brakes for one second.
4. When the engine braking effect becomes insufficient.

25. What is the correct steering action when a vehicle begins to slide sideways during a skid?

1. Steer quickly in the direction you want the vehicle to go.
2. Keep the steering wheel straight to maintain momentum.
3. Steer slowly in the opposite direction of the slide.
4. Turn the wheel sharply against the direction of travel.