What can rust around a commercial vehicle’s wheel nuts indicate?
Correct answer: The nuts may be loose
Rust trails around wheel nuts can be evidence of movement and looseness.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.1.3, What to Look For > Wheel and Rim Problems; printed p. 2-2, physical PDF page 31. ↗
When should a commercial driver select the proper low gear for a downgrade?
Correct answer: Before starting down the grade
The gear must be selected before descending because shifting later may be unsafe or impossible.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.16.2, Select the Right Gear Before Starting Down the Grade; printed p. 2-40, physical PDF page 69. ↗
Why might an empty cargo van require more overhead clearance than the same van when loaded?
Correct answer: Its suspension may sit higher when empty
Removing cargo can raise the vehicle, so a clearance that worked while loaded may no longer be sufficient.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.7.4, Space Overhead; printed p. 2-23, physical PDF page 52. ↗
What does a single vehicle’s gross vehicle weight rating (GVWR) represent?
Correct answer: Its manufacturer-specified loaded weight rating
GVWR is a rating specified by the manufacturer, not the actual scale reading for a particular trip.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.2.1, Definitions You Should Know > Gross Vehicle Weight Rating; printed p. 3-2, physical PDF page 84. ↗
Why should a driver check cargo covers in the mirrors while traveling?
Correct answer: A loose cover can tear away, expose cargo, or block someone's view
A flapping cover can detach and create a visibility or roadway hazard.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.3.4, Covering Cargo; printed p. 3-3, physical PDF page 85. ↗
You are approaching a curve in a commercial vehicle with a manual transmission. When should you reduce speed and select the appropriate lower gear?
Correct answer: Before entering the curve
Slow to a safe speed and select the proper gear before the curve. This helps you maintain stable control rather than needing a gear change during the turn.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.3.1, Manual Transmissions > Before Entering a Curve; printed p. 2-14, physical PDF page 43. ↗
Before departure, why should you secure loose tools and other articles in the cab?
Correct answer: They can obstruct controls or strike occupants during a collision
Loose articles can interfere with vehicle controls or become impact hazards. Secure them before driving rather than relying on their current resting position.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.1.5, Seven-step Inspection Method > Step 6 > Get In Vehicle; printed p. 2-10, physical PDF page 39. ↗
At dusk in rain, are identification and clearance lights alone sufficient to make your truck visible?
Correct answer: No, use headlights too
Clearance lamps do not replace headlights in reduced visibility.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.5.2, Communicating Your Presence > When It Is Hard to See; printed p. 2-17, physical PDF page 46. ↗
Snow covers the truck's mirrors and side windows before departure. What is needed for a safe start?
Correct answer: Clear them as well as the windshield
You need usable views around the vehicle before entering traffic.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.13.1, Vehicle Checks > Windows and Traffic Monitoring Devices / Mirrors; continued physical 65, printed 2-36; printed p. 2-35, physical PDF page 64. ↗
When is it safe to open the pressurized radiator system for a coolant check?
Correct answer: After it has cooled, following the vehicle’s instructions
Hot pressurized coolant can cause severe burns. Engine shutdown alone does not release that danger.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.14.1, Vehicle Checks > Engine Coolant; printed p. 2-37, physical PDF page 66. ↗
Why is listening for a horn alone an unsafe crossing check?
Correct answer: Cab noise may hide the horn until the train is dangerously close
Do not depend on hearing a horn. Check for trains and obey crossing controls before proceeding.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.15.3, Driving Procedures > Do Not Expect to Hear a Train; printed p. 2-39, physical PDF page 68. ↗
Smoke indicates a vehicle fire while you are driving. Where should you stop if you can safely move off the road?
Correct answer: An open area clear of combustible surroundings
Stop safely away from things that could ignite and notify emergency services.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.21.3, Fire Fighting > Pull Off the Road; printed p. 2-47, physical PDF page 76. ↗
A B:C extinguisher is intended for which hazards?
Correct answer: Flammable-liquid and electrical fires
Match the rating to the fire; do not assume one extinguisher covers every material.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.21.3, Fire Fighting > Use the Right Fire Extinguisher: B:C prose; printed p. 2-47, physical PDF page 76. ↗
What makes a dry-bulk tank load demanding in a sharp curve?
Correct answer: A high center of gravity and possible load movement
Reduce speed before curves and avoid abrupt maneuvers.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.4.1, Dry Bulk; printed p. 3-4, physical PDF page 86. ↗
Your load is within the legal maximum. Does that guarantee it is safe for bad weather or a mountain route?
Correct answer: No, conditions can require operating below legal maximum weight
Legal limits do not replace judgment about braking, traction, and the route.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.2.2, Legal Weight Limits; printed p. 3-2, physical PDF page 84. ↗
Your eyelids are heavy and you are struggling to stay alert. What is the safe response?
Correct answer: Stop at a safe place and sleep
Temporary stimulation does not replace sleep or make continued drowsy driving safe.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.11.5, Night Driving Procedures > If You Get Sleepy, Stop at the Nearest Safe Place; fatigue guidance physical 62, printed 2-33; printed p. 2-35, physical PDF page 64. ↗
Your truck’s brakes have failed on a downgrade and an escape ramp is available. What should you do?
Correct answer: Use the escape ramp
A designated escape ramp offers a means to stop a runaway vehicle; delay increases danger.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.17.3, Brake Failure > Brake Failure on Downgrades; printed p. 2-42, physical PDF page 71. ↗
Why should a commercial driver keep required hazardous-material shipping papers easy to find?
Correct answer: Responders may need to identify the cargo when the driver cannot speak
Accessible cargo information helps emergency personnel choose suitable precautions.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.23.2, Why Are There Rules? > To Communicate the Risk: shipping papers; printed p. 2-51, physical PDF page 80. ↗
A freight container is designed to transfer between a truck chassis, a train and a ship. What kind of container is it?
Correct answer: An intermodal container
Intermodal means the container can be used across two or more transport modes; the cargo still needs appropriate securement.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.3.5, Sealed and Containerized Loads; printed p. 3-3, physical PDF page 85. Corroboration/qualification: 393.126 - Intermodal Containers, https://www.fmcsa.dot.gov/regulations/cargo-securement/cargo-securement-rules, reviewed 2026-09-12. ↗
Why check the rated capacity of a coupling device before assigning a load?
Correct answer: It has limits on the weight it can pull or carry
A coupling has its own rated limit for weight pulled or carried. Check that rating along with the vehicle, axle, tire and applicable legal limits.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.2.1, Definitions You Should Know > Coupling Device Capacity; printed p. 3-2, physical PDF page 84. ↗
