10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free IA-CDL questions are organized by exam domain, so you can see how each part of the Iowa CDL Permit Test blueprint is tested. Reveal the answer and explanation under each question.
A power unit has a GVWR of 22,000 pounds and tows a trailer with a GVWR of 12,500 pounds. The combination has a GCWR of 34,500 pounds. Assuming no passenger or hazardous-material issue, what CDL class is required?
Correct answer: B - Class A; the combination meets both Class A rating thresholds
A 70-foot tractor-trailer is traveling 55 mph on a dry road in light traffic. Applying the CDL following-distance rule for good conditions, the driver needs at least:
Correct answer: D - 8 seconds
Without warning, the right-front tire blows while a loaded straight truck is moving at highway speed. The truck is still tracking within its lane. What should the driver do before making any deliberate braking input?
Correct answer: A - Grip the wheel firmly, hold course, and avoid braking until speed drops
A 21-foot crated shipment weighing 14,000 pounds is blocked against forward movement by a rated bulkhead. Three tie-downs provide a verified aggregate WLL of 9,000 pounds. Which securement audit conclusion is correct?
Correct answer: C - Sufficient; the tie-down count is three and aggregate WLL exceeds 7,000 pounds
Before a long downgrade, a driver selects a low gear and establishes 40 mph as the safe speed. When the vehicle returns to 40 mph, select the controlled-braking cycle that limits brake fade.
Correct answer: B - Brake firmly to about 35 mph in roughly three seconds, then release
During a pre-trip air test on a tractor-semitrailer, the engine is off, the parking brakes are released, and the service brake is not applied. After stabilization, pressure falls 3.4 psi in one minute. How should the driver score this released-brake leakage test?
Correct answer: B - A failure; released-brake loss must be less than 3 psi in one minute
An air-braked bus completes its ABS self-check, but the yellow ABS lamp stays on. The service brakes feel normal during a low-speed check. What does the persistent lamp indicate?
Correct answer: D - Normal braking remains, but ABS may be unavailable and needs repair
While checking the low-air warning, a driver repeatedly applies the brakes. Both gauges reach 52 psi before any visual or audible warning appears. Which system has failed its functional check?
Correct answer: A - The low-air warning; it should activate before pressure drops below 55 psi
After coupling, a tug test holds, yet the visual inspection shows a gap between the upper and lower fifth-wheel plates and the jaws appear closed around the kingpin head. The landing gear is still down. What must the driver do before departure?
Correct answer: D - Secure the rig, then recouple until the plates meet and the jaws lock on the shank
During a brake check, the tractor brakes apply normally but the trailer service brakes do not. The red emergency line is intact, the trailer reservoirs are charged, and the blue service line is severed. Which diagnosis accounts for the result?
Correct answer: C - The foot-brake signal cannot reach the trailer service brakes through the severed blue line
The full bank has 1,020 more IA-CDL questions with explanations.
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