Pennsylvania CDL Knowledge Test Sample Questions
Real, Pennsylvania-specific sample questions from our practice question bank, with the correct answer, a full explanation, and a source reference for each. See our national sample questions for topics that apply to every state, or take the full Pennsylvania cdl practice test to test yourself instead of just reading the answers.
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1. What happens to an air brake system's spring brakes when air pressure drops too low?
Spring brakes are held back by air pressure; when pressure drops too low, they apply automatically to prevent a runaway vehicle.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Air Brakes
2. If the drive wheels start to skid from over-acceleration on a slick road, what should the driver do?
Easing off the accelerator allows the drive wheels to regain traction; hard braking or sharp steering can make the skid worse.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Skid Control
3. How soon after starting a trip should a driver first re-check cargo securement?
Cargo securement should be checked within the first 50 miles of a trip, then again about every 150 miles or 3 hours.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Cargo Securement
4. Under federal hours-of-service rules, how many hours may most property-carrying drivers drive after 10 consecutive hours off duty?
Federal hours-of-service rules allow most property-carrying drivers up to 11 hours of driving after 10 consecutive hours off duty.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Hours of Service
5. When required to stop at a railroad crossing, how far from the nearest rail should a commercial vehicle stop?
A commercial vehicle required to stop at a crossing should stop no closer than 15 feet and no farther than 50 feet from the nearest rail.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Railroad Crossings
6. Why do larger commercial vehicles require more following distance than passenger cars?
The greater weight and size of a commercial vehicle increases the distance it needs to stop safely.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Space Management
7. What is the main reason a commercial driver performs a pre-trip inspection?
A careful pre-trip inspection catches mechanical issues before they turn into a breakdown or crash on the road.
Source: PennDOT, Pennsylvania Commercial Driver's Manual, Vehicle Inspection