During the truck walk-around, you find tire fabric visible through a cut in the sidewall. The tire still holds air. What should you conclude?
Correct answer: Holding air does not make the tire safe; the damage needs correction before use.
Exposed fabric from a tire cut or other damage is a defect to identify during inspection. Air pressure alone does not establish that a damaged tire is safe.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.1.3 What to Look For - Tire Problems; physical PDF page 42. ↗
After pumping a hydraulic brake pedal, you hold steady pressure and the pedal slowly sinks. What is the appropriate response?
Correct answer: Have the possible hydraulic leak or other brake problem corrected before driving.
The manual describes holding the pedal after pumping it as a hydraulic leak check. A moving pedal during the hold indicates a problem that must be corrected.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.1.5 Step 7 - Test for Hydraulic Leaks; physical PDF page 48. ↗
You must back a tall truck into an unfamiliar loading area. What should the preliminary walk-through include?
Correct answer: Ground-level obstacles, side clearance, and overhead clearance along the entire path.
Before backing, get out and inspect the path. A clear pavement surface does not establish clearance from branches, wires, canopies, or side obstructions.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.2.4 Backing Safely - Look at Your Path; physical PDF page 50. ↗
A helper will watch the blind area while you back toward a dock. What must you agree on before the truck moves?
Correct answer: Clear hand signals, especially the signal that means stop.
A helper supplements the driver’s checks. Agreed signals, particularly a stop signal, prevent confusion during backing.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.2.4 Backing Safely - Use a Helper; physical PDF page 50. ↗
In ordinary conditions, which scanning plan follows the CDL manual’s guidance for anticipating trouble ahead?
Correct answer: Look about 12 to 15 seconds ahead while also checking nearer traffic and the mirrors.
The manual recommends a 12-to-15-second look-ahead range. It is a scanning guide, not a reason to ignore nearby hazards or mirrors.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.4.1 Seeing Ahead; physical PDF page 51. ↗
A car looks small and far away in your truck’s curved mirror. How should this affect a lane-change decision?
Correct answer: Allow for the mirror making objects appear smaller and farther away than they are.
Convex mirrors expand the field of view but distort apparent size and distance. Use the complete mirror-check routine and a genuinely safe gap.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.4.2 Seeing to the Sides and Rear - Using Mirrors; physical PDF page 52. ↗
A loaded truck approaches a curve with a posted advisory speed commonly used by cars. What is the safest plan?
Correct answer: Reduce speed before entering; the posted curve speed may still be too fast for the truck.
A truck’s load and center of gravity affect its safe curve speed. Slow before the curve instead of relying on a speed suitable for a passenger car.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.6.3 Speed and Curves; physical PDF page 56. ↗
Your headlights reveal less clear roadway than the distance your truck needs to stop. What adjustment is needed?
Correct answer: Slow enough to stop within the roadway you can see is clear.
Do not drive faster than the available sight distance permits. Darkness, hills, curves, and weather can all shorten the clear distance ahead.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.6.4 Speed and Distance Ahead; physical PDF page 56. ↗
Under good conditions, a 40-foot commercial vehicle is traveling at 55 mph. What following interval matches the manual’s length-and-speed guideline?
Correct answer: At least five seconds.
The manual recommends one second per 10 feet of vehicle length below 40 mph, plus one additional second above 40 mph. Forty feet at 55 mph gives five seconds; adverse conditions require more.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.7.1 Space Ahead; physical PDF page 57. ↗
The truck starts to hydroplane across standing water. Which response helps the tires regain contact?
Correct answer: Ease off the accelerator and avoid hard braking or abrupt steering.
Hydroplaning reduces tire contact with the road. Ease off power and let the vehicle slow without abrupt inputs; the manual also discusses disengaging the clutch where applicable.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.6.2 Matching Speed to the Road Surface - Hydroplaning; physical PDF page 56. ↗
The pavement is wet on a cold day, but a bridge ahead looks unusually dry and dark. What should you allow for?
Correct answer: The bridge may be icy even though nearby pavement is only wet.
Bridges can freeze before other road surfaces, and ice may not be obvious. Make smooth control inputs and reduce speed before reaching a suspect surface.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.6.2 Matching Speed to the Road Surface - Bridges; physical PDF page 56. ↗
You are approaching an icy stretch with the retarder switched on. What does the CDL manual recommend?
Correct answer: Turn the retarder off when traction is poor.
Retarders act through the drive wheels and can cause a skid on slippery surfaces. The manual advises turning them off in poor-traction conditions.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.3.4 Retarders; physical PDF page 51. ↗
After a long drive on a hot day, a properly inflated tire shows a higher pressure than its cold reading. Should you bleed air to restore the cold reading?
Correct answer: No; normal heating raises pressure, and bleeding air can leave the tire underinflated when it cools.
Do not let air out of hot tires simply because their pressure has risen. If a tire is excessively hot, stop safely and let it cool while addressing the cause.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.14.1 Vehicle Checks - Tires; physical PDF page 70. ↗
Your loaded truck is about to descend a long, steep grade. When should you select the suitable low gear?
Correct answer: Before starting down the grade, while speed is under control.
Plan the safe speed and gear before descending. Engine braking should carry much of the speed-control load; late downshifting can fail when engine speed is too high.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.16.2 Select the Right Gear Before Starting Down the Grade; physical PDF page 74. ↗
A traffic queue beyond a railroad crossing leaves room for the tractor but not the entire trailer. What should you do?
Correct answer: Wait before the tracks until the whole combination can clear them without stopping.
The entire vehicle must be able to get across and clear the tracks. Never enter a crossing when congestion may trap part of the combination on it.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.15.5 Crossing the Tracks; physical PDF page 73. ↗
On a slippery curve, the truck keeps sliding straight despite your steering input. What is the useful response?
Correct answer: Reduce the demand on the front tires and slow down so they can regain traction.
A front-wheel skid means the front tires lack traction to steer. More steering does not restore that traction; reduce the cause of the skid and slow the vehicle.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.19.3 Front-wheel Skids; physical PDF page 79. ↗
A driver is struggling to stay awake and considers taking a stimulant to finish the delivery. What is the sound safety decision?
Correct answer: Stop safely and rest rather than use a drug to hide fatigue.
The manual warns against masking fatigue with drugs. Rest addresses fatigue; temporary alertness tricks do not make a tired driver reliably safe.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.11.2 Driver Factors - Fatigue and Lack of Alertness, continued; physical PDF page 68. ↗
A cold medicine is sold without a prescription, but its label warns of drowsiness. What should a commercial driver understand?
Correct answer: Nonprescription medicine can still impair safe driving.
Legal medicines, including cold remedies, can affect alertness and safe operation. Follow warnings and appropriate medical advice rather than treating nonprescription status as proof of safety.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 2.22.2 Other Drugs; physical PDF page 83. ↗
Warehouse staff loaded your unsealed trailer while you completed paperwork. Who remains responsible for checking that the cargo is safe to transport?
Correct answer: You, the driver, even though someone else performed the loading.
The driver remains responsible for safe loading, weight, balance, and securement. Having another person load the vehicle does not remove those responsibilities.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 3 Transporting Cargo Safely - Driver Responsibility; physical PDF page 87. ↗
Two loads have the same weight. One stacks the heaviest freight high; the other puts it low. Which arrangement better resists rollover?
Correct answer: The arrangement with the heaviest freight kept low.
Keeping heavy cargo low lowers the center of gravity. Weight distribution affects stability even when total vehicle weight does not change.
Source: South Dakota Commercial Driver License Manual, Revised 07/2025, 3.2.3 Don't Be Top-heavy; physical PDF page 88. ↗
