Question 1
A straight truck has a GVWR of 28,000 lb and tows a trailer with a GVWR of 9,000 lb. It is not carrying passengers or placardable hazardous materials. Which CDL class is required?
Show answer & explanation
Correct answer: B - Class B
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A straight truck has a GVWR of 28,000 lb and tows a trailer with a GVWR of 9,000 lb. It is not carrying passengers or placardable hazardous materials. Which CDL class is required?
Correct answer: B - Class B
A 60-foot tractor-trailer is traveling 55 mph on a dry road with good visibility. Before adding any extra cushion for traffic or weather, what minimum following interval should the driver maintain?
Correct answer: D - 7 seconds
A driver checked the cargo at departure and again within the first 50 miles. Thirty miles later, the driver changes duty status at a terminal; only 90 minutes have passed since the last check. What must happen before the trip continues?
Correct answer: A - Reinspect the cargo and securement
During a pre-trip inspection, a steering-axle tire measures 3/32 inch of tread in a major groove. A drive-axle tire also measures 3/32 inch, and neither tire has another defect. Which interpretation is correct?
Correct answer: C - Only the steering-axle tire fails the tread requirement
A tractor-trailer's front tire blows at highway speed, and the tractor pulls sharply toward the failed tire. The driver still has directional control. Which response best preserves control?
Correct answer: D - Hold the wheel firmly, avoid braking at first, let speed fall, then brake gently
During the applied air-leakage test on a combination vehicle, the engine is off, the parking brakes are released, and the foot brake is held after the initial pressure drop stabilizes. Pressure falls from 118 psi to 113 psi in one minute. How should the driver interpret the result?
Correct answer: B - The leak rate is excessive; repair is required before operation
While fanning the brakes during a controlled pre-trip test, the low-air warning first activates at 57 psi. The spring brakes have not begun to apply. What does this finding mean?
Correct answer: C - The low-air warning failed; repair is required
After the normal self-check and a short roll, the tractor's ABS warning lamp remains on. A 5-mph service-brake check stops the vehicle straight, and the air-pressure and leakage tests are normal. What is the best course of action?
Correct answer: A - Drive cautiously and arrange prompt ABS repair
After a tractor backs under a semitrailer, the tug test holds. The visual check then shows daylight between the trailer apron and fifth wheel, and the jaws appear to be around the kingpin head rather than the shank. What should the driver do?
Correct answer: B - Uncouple, correct the trailer height, and couple again
In a yard maneuver, the blue trailer air line separates while the red supply line remains connected and the trailer tanks stay charged. Which change should the driver expect?
Correct answer: A - Trailer service-brake response will be lost or reduced
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