Under federal rules for an interstate bus, which tires are prohibited on its front wheels?
Correct answer: Regrooved, recapped, or retreaded tires
A bus may not use regrooved, recapped, or retreaded tires on its front wheels.
Source: 49 CFR 393.75(d), bus front tires; eCFR Title 49 current through 2026-09-10, reviewed 2026-09-12. Interstate CMV scope. Related PA study passage: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.1.3, What to Look For > Tire Problems: bus front tires; printed p. 2-2, physical PDF page 31. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=31 ↗
What is the principal method for controlling speed on a long downgrade?
Correct answer: Engine braking in a suitable low gear
Selecting a low gear before descending lets engine braking control speed while preserving the service brakes.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.16.1, Select a Safe Speed: engine braking; printed p. 2-40, physical PDF page 69. ↗
How should a commercial driver respond to a vehicle following too closely?
Correct answer: Increase the space ahead and avoid sudden changes
More room ahead reduces the need for sudden braking and gives the tailgater an opportunity to pass.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.7.2, Space Behind > Dealing with Tailgaters Safely; printed p. 2-22, physical PDF page 51. ↗
On an interstate truck trip, after the initial check of an accessible, unsealed load, when must you next recheck securement?
Correct answer: At a duty-status change, 3 hours of driving, or 150 miles, whichever occurs first
Recheck securement at the first of these events: a change of duty status, three driving hours, or 150 miles. Make needed adjustments before continuing.
Source: 49 CFR 392.9(b)(3)(i)-(iii) and (b)(4), reinspection triggers and exceptions; eCFR Title 49 current through 2026-09-10, reviewed 2026-09-12. Interstate CMV scope. Related PA study passage: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.1, Inspecting Cargo > Re-check; printed p. 3-1, physical PDF page 83. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=83 ↗
An interstate truck carries a 7-foot article under the general federal tiedown rule. It is not blocked against forward movement. What is the minimum tiedown count?
Correct answer: Two
An article longer than 5 feet and no longer than 10 feet needs at least two tiedowns when it is not blocked against forward movement. Required working load limit and any cargo-specific rules still apply.
Source: 49 CFR 393.110(a), (b)(2)(ii), and (d), general tiedown minimum and special-purpose exception; eCFR Title 49 current through 2026-09-10, reviewed 2026-09-12. Interstate CMV scope. Related PA study passage: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.3.2, Cargo Tie-Down: tiedown count; printed p. 3-3, physical PDF page 85. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=85 ↗
The drive wheels begin spinning as you accelerate from a stop on a snowy road. What response does the handbook recommend?
Correct answer: Ease off the accelerator to stop the wheel spin
Too much power on a low-traction surface can make the drive wheels spin and cause loss of control. Remove your foot from the accelerator and use gradual acceleration suited to the available traction.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.2.1, Accelerating; printed p. 2-12, physical PDF page 41. ↗
What is the safest way to make routine mirror checks while traveling?
Correct answer: Use brief checks and return attention to the road ahead
Frequent, brief mirror checks help you monitor surrounding traffic without traveling a long distance while looking away from the road ahead.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.4.2, Seeing to the Sides and Rear > How to Use Traffic Monitoring Devices / Mirrors; printed p. 2-16, physical PDF page 45. ↗
An interstate truck breaks down on a straight rural two-way highway. Why place required warning devices both ahead and behind?
Correct answer: Traffic can approach the stopped vehicle from either direction
Traffic approaches from both directions. The federal layout has a device about 100 feet in each direction and one on the traffic side about 10 feet toward approaching traffic. Hills, curves and other obstructions require different placement.
Source: 49 CFR 392.22(b)(1)(i)-(iii) and (b)(2)(iv), two-direction layout and obstructed-view exception; eCFR Title 49 current through 2026-09-10, reviewed 2026-09-12. Interstate CMV scope. Related PA study passage: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.5.2, Communicating Your Presence > two-way/undivided highway; Figure 2.9; printed p. 2-18, physical PDF page 47. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=47 ↗
An aggressive driver tries to provoke you. What is the safer response?
Correct answer: Create separation and avoid challenging the driver
Do not turn another driver’s aggression into a contest.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.10.3, What You Should Do When Confronted by an Aggressive Driver; printed p. 2-31, physical PDF page 60. ↗
During a hot-weather stop, a tire is too hot to touch. What does the handbook direct you to do?
Correct answer: Remain stopped until it cools
Continuing with an overheated tire increases the risk of failure or fire.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.14.1, Vehicle Checks > Tires; printed p. 2-36, physical PDF page 65. ↗
A railroad crossing has no active lights or gates. What does that mean for your decision?
Correct answer: You must look and listen and determine that crossing is safe
The absence of active warning equipment does not mean no train is coming. Look and listen, make sure there is room to clear the tracks, and obey any applicable stopping requirement.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.15.1, Types of Crossings > Passive Crossings; also physical 68, printed 2-39, 2.15.4; printed p. 2-37, physical PDF page 66. ↗
You stop to help at a collision in which your truck was not involved. Where should you park?
Correct answer: Away from the immediate scene so emergency vehicles have space
Helping should not obstruct rescuers or create a second hazard.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.20.1, Protect the Area: parking when stopping to help; printed p. 2-46, physical PDF page 75. ↗
You do not know which extinguishing agent is safe for the burning cargo. What should you do?
Correct answer: Stay clear and wait for trained firefighters
An unsuitable agent can worsen a fire, especially when hazardous materials are involved.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.21.3, Fire Fighting > Use the Right Fire Extinguisher: uncertainty about the agent; printed p. 2-47, physical PDF page 76. ↗
An interstate truck carries a sealed load that you are ordered not to open. Which duty still remains?
Correct answer: Check compliance with gross and axle weight limits
The sealed-load inspection exception does not waive gross or axle weight limits. Check those limits without treating the seal as proof that the vehicle is not overloaded.
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: 49 CFR 392.9(b)(4), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-III/subchapter-B/part-392/subpart-A/section-392.9, reviewed 2026-09-12. ↗
What does axle weight measure?
Correct answer: Weight transmitted to the ground by an axle or axle group
Axle loading is a separate limit from the vehicle’s total gross weight.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.2.1, Definitions You Should Know > Axle Weight; printed p. 3-2, physical PDF page 84. ↗
Why clean both sides of the windshield before a night trip?
Correct answer: Dirt can scatter light and worsen glare
Interior film as well as exterior dirt can obscure the road under bright lights.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.11.4, Vehicle Factors > Windshield and Traffic Monitoring Device / Mirror; printed p. 2-34, physical PDF page 63. ↗
Which combination matters when selecting a safe descent speed?
Correct answer: Vehicle weight, grade length and steepness, road and weather
Different loads and grades can demand different descent speeds even under the same posted limit.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.16.1, Select a Safe Speed; printed p. 2-40, physical PDF page 69. ↗
A cardboard box in your lane looks empty. What should you remember when planning how to avoid it?
Correct answer: It may conceal a solid or heavy object
A harmless-looking box or sack may contain something that damages tires, wheels or other parts. Look far enough ahead to avoid debris without a sudden, unsafe maneuver.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.8.2, Hazardous Roads > Foreign Objects; printed p. 2-26, physical PDF page 55. ↗
In its basic steering-defect guidance, what amount of steering-wheel free play does the Pennsylvania CDL manual warn can make steering difficult?
Correct answer: More than 10 degrees
The manual warns about more than 10 degrees of play. This is inspection guidance, not one universal regulatory limit: federal steering-lash limits vary with wheel diameter and steering-system type.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.1.3, What to Look For > Steering System Defects; printed p. 2-3, physical PDF page 32. Corroboration/qualification: 49 CFR 393.209(b), https://www.ecfr.gov/current/title-49/subtitle-B/chapter-III/subchapter-B/part-393/subpart-J/section-393.209, reviewed 2026-09-12. ↗
Two legal parking spaces are equally suitable for your truck. One allows a forward exit; the other requires backing into traffic. Which is preferable?
Correct answer: The space that allows you to pull forward when leaving
Plan parking to avoid reversing when possible because you cannot see everything behind a large vehicle.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.2.4, Backing Safely: avoiding backing; printed p. 2-12, physical PDF page 41. ↗
