SD CDL - South Dakota Commercial Drivers License Pre-Trip Vehicle Inspection Questions and Answers — Questions and Answers
Question 1: During the in-cab portion of the pre-trip inspection, what is the minimum required tread depth for the front steering axle tires?
- 2/32 inch
- 4/32 inch (Correct answer)
- 6/32 inch
- It is not required to check tread depth during the in-cab inspection.
Correct answer: 4/32 inch
Federal and state regulations require a minimum tread depth of 4/32 of an inch on all steering axle tires to ensure proper grip and handling. Drive and trailer tires require a minimum of 2/32 inch.
Question 2: A driver performing a pre-trip inspection on a vehicle with air brakes notices that the low-pressure warning light and buzzer activate. At or before what pressure must this warning occur?
- 90 PSI
- 100 PSI
- 55 PSI (Correct answer)
- 20 PSI
Correct answer: 55 PSI
According to the standardized CDL air brake check procedure, the low air pressure warning devices (light and/or buzzer) must activate at or before the pressure drops to 55 PSI to provide the driver with adequate warning of a potential braking system failure.
Question 3: Which of the following items is NOT a required piece of emergency equipment that must be checked during a pre-trip inspection?
- A properly rated and fully charged fire extinguisher
- Three red reflective triangles
- Spare electrical fuses (unless the vehicle uses circuit breakers)
- A first-aid kit (Correct answer)
Correct answer: A first-aid kit
While a first-aid kit is highly recommended, federal regulations specifically mandate that a commercial motor vehicle must be equipped with a fire extinguisher, spare fuses (if applicable), and warning devices for stopped vehicles (such as three reflective triangles).
Question 4: When inspecting the steering system, what is the maximum amount of acceptable play or 'slack' in a 20-inch steering wheel?
- 4 inches
- 1 inch
- 3 inches
- 2 inches (Correct answer)
Correct answer: 2 inches
The acceptable limit for steering wheel play is 10 degrees, which translates to approximately 2 inches of movement at the rim of a 20-inch steering wheel. Exceeding this amount could indicate worn steering components and is considered unsafe.
Question 5: A driver is about to begin their pre-trip inspection for the day. Before inspecting any components, what is the very first step they must legally take according to 49 CFR 396.13?
- Start the engine to build air pressure.
- Check the oil and coolant levels.
- Review the previous driver's Driver Vehicle Inspection Report (DVIR). (Correct answer)
- Ensure the vehicle is clean.
Correct answer: Review the previous driver's Driver Vehicle Inspection Report (DVIR).
Federal regulation 49 CFR 396.13 explicitly requires a driver to review the last DVIR prepared for the vehicle. They must be satisfied that any listed safety-related defects have been repaired before operating the vehicle.
Question 6: During the walk-around inspection of a combination vehicle, what is a critical check for the fifth wheel assembly after coupling to a trailer?
- Ensuring the fifth wheel is freshly painted.
- Checking that there is a visible gap between the fifth wheel and the trailer apron.
- Verifying that the locking jaws are fully closed around the kingpin and the release handle is in the locked position. (Correct answer)
- Confirming the air lines have been painted red and blue.
Correct answer: Verifying that the locking jaws are fully closed around the kingpin and the release handle is in the locked position.
A secure connection is paramount. The driver must visually confirm that the locking jaws have properly engaged the trailer's kingpin. There should be no gap between the trailer apron and the fifth wheel skid plate, and the release handle must be in the correct position. A tug test should also be performed.
SD CDL - South Dakota Commercial Drivers License Pre-Trip Vehicle Inspection Questions and Answers
During the in-cab portion of the pre-trip inspection, what is the minimum required tread depth for the front steering axle tires?