SD CDL - South Dakota Commercial Drivers License Basic Vehicle Control Questions and Answers — Questions and Answers
Question 1: When backing a large commercial vehicle, what is the most important safety practice to follow?
- Relying solely on your mirrors to see what is behind you.
- Backing up as quickly as possible to minimize traffic disruption.
- Getting out of the vehicle to look at your path of travel before backing. (Correct answer)
- Assuming your path is clear if you just checked it a few minutes ago.
Correct answer: Getting out of the vehicle to look at your path of travel before backing.
The most critical safety step before backing is to get out and walk around the vehicle (G.O.A.L. - Get Out And Look). This allows the driver to identify any obstacles, hazards, or changes in the environment that are not visible in the mirrors. Conditions can change quickly, and relying only on mirrors creates dangerous blind spots.
Question 2: You are driving a truck with a manual transmission. To accelerate smoothly from a stop, you should:
- Release the clutch quickly while pressing hard on the accelerator.
- Slowly release the clutch while gently pressing the accelerator. (Correct answer)
- Press the accelerator to the floor before releasing the clutch.
- Keep the clutch pressed halfway down while accelerating.
Correct answer: Slowly release the clutch while gently pressing the accelerator.
To achieve a smooth start in a manual transmission vehicle, the driver must coordinate the gradual release of the clutch with a gentle application of the accelerator. This allows the engine to engage with the transmission without jerking or stalling the vehicle. Releasing the clutch too fast or applying too much throttle will result in a rough, jerky start.
Question 3: Which of the following best describes the primary purpose of a vehicle's retarder?
- To bring the vehicle to a rapid stop in an emergency.
- To help slow the vehicle and reduce wear on the service brakes. (Correct answer)
- To engage the parking brake automatically on steep grades.
- To improve traction on slippery road surfaces.
Correct answer: To help slow the vehicle and reduce wear on the service brakes.
Retarders (such as engine brakes or exhaust brakes) are designed to help slow a vehicle, particularly on long downgrades, which reduces the need to use the service brakes. This helps prevent the service brakes from overheating and fading, and it reduces wear, ensuring the brakes are in good condition for when they are truly needed for stopping.
Question 4: A driver is preparing to make a right turn in a large truck. To execute the turn properly without hitting the curb, the driver must:
- Keep the rear of the trailer as close to the curb as possible throughout the turn.
- Turn the steering wheel sharply as soon as the front of the truck reaches the corner.
- Swing wide to the left before starting the turn to allow the rear wheels to clear the corner. (Correct answer)
- Accelerate quickly through the turn to reduce the turning radius.
Correct answer: Swing wide to the left before starting the turn to allow the rear wheels to clear the corner.
Large vehicles exhibit "off-tracking," where the rear wheels follow a shorter path than the front wheels during a turn. To compensate for this and prevent the rear wheels from running over the curb or sidewalk, the driver must steer the front of the vehicle wide into the intersection, a maneuver often called a "button hook" turn.
Question 5: Under which condition should a driver AVOID using an engine retarder or "jake brake"?
- When driving on a long, steep downgrade.
- When driving on dry pavement in clear weather.
- When the roadway is wet, icy, or covered in snow. (Correct answer)
- When approaching a stop sign on a level road.
Correct answer: When the roadway is wet, icy, or covered in snow.
Retarders apply braking force only to the drive wheels. On surfaces with poor traction, such as those that are wet, icy, or snow-covered, using the retarder can cause the drive wheels to lock up and skid, potentially leading to a loss of vehicle control. Therefore, retarders should be turned off in such conditions.
Question 6: When shifting up in a heavy vehicle with a non-synchronized manual transmission, the proper technique is to:
- Push the clutch in once and quickly shift to the next higher gear.
- Release the accelerator, push the clutch in, shift to neutral, release the clutch, then push the clutch in again to shift to the next gear. (Correct answer)
- Keep the accelerator pressed down while quickly shifting gears.
- Shift directly from a low gear to a high gear, skipping the gears in between.
Correct answer: Release the accelerator, push the clutch in, shift to neutral, release the clutch, then push the clutch in again to shift to the next gear.
Most heavy-duty trucks with manual transmissions are non-synchronized and require the driver to double-clutch when shifting up or down. The process involves using the clutch to move the transmission to neutral, and then using the clutch a second time to engage the next gear, matching the engine RPM to the road speed.
SD CDL - South Dakota Commercial Drivers License Basic Vehicle Control Questions and Answers
When backing a large commercial vehicle, what is the most important safety practice to follow?