Under federal rules for an interstate commercial truck, what minimum tread depth is required in the front tires' major grooves?
Correct answer: 4/32 inch
Front tires on buses, trucks and truck tractors need at least 4/32 inch in major grooves; the general minimum for other tires is 2/32 inch. Do not measure on tie bars, humps or fillets.
Source: 49 CFR 393.75(b)-(c), front-tire tread and excluded tie bars, humps and fillets; 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; 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 ↗
Why should you follow a consistent sequence when inspecting your commercial vehicle?
Correct answer: It reduces the chance of overlooking a component
Following the same inspection method helps you remember the checks and notice problems before driving.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.1.5, Seven-step Inspection Method > Method of Inspection; printed p. 2-5, physical PDF page 34. ↗
Under the handbook's vehicle-length following rule, what extra time should be added above 40 mph?
Correct answer: One additional second
Start with at least one second per 10 feet of vehicle length, then add one second above 40 mph. Poor road or weather conditions require more space.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.7.1, Space Ahead > How Much Space?; printed p. 2-22, physical PDF page 51. ↗
On an interstate truck trip, when must you first recheck an accessible, unsealed load's securement?
Correct answer: Within the first 50 miles
The federal rule requires inspection within the first 50 miles and correction of insecure loading. It separately excepts sealed loads the driver is ordered not to open and loads that cannot practicably be inspected.
Source: 49 CFR 392.9(b)(2) and (b)(4), initial cargo reinspection 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 > After Starting; 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 ↗
Under federal rules for an interstate truck load, what minimum aggregate working load limit must tiedowns securing an article provide?
Correct answer: At least half the secured article's weight
The counted aggregate must be at least half the secured article's weight. Count half a tiedown's rating when it runs directly to the cargo or returns to the same vehicle side, and its full rating when it passes over, through or around the cargo to the opposite side. Additional cargo-specific requirements can apply.
Source: 49 CFR 393.106(a) and (d)(1)-(3), applicability and aggregate working load limit; 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: working load limit; 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 ↗
Before backing with a helper, which signal should you both agree on?
Correct answer: A clear stop signal
Keep the helper visible and agree on understood hand signals before backing. A clear stop signal is especially important.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.2.4, Backing Safely > Use a Helper When You Can; printed p. 2-13, physical PDF page 42. ↗
You are looking 12 to 15 seconds ahead as recommended for commercial driving. How should you also monitor the nearer road?
Correct answer: Shift attention between distant and nearby conditions
Looking well ahead does not replace monitoring nearby hazards. The handbook describes shifting attention back and forth between near and far to maintain awareness.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.4.1, Seeing Ahead > How Far Ahead to Look; printed p. 2-15, physical PDF page 44. ↗
An interstate truck breaks down on a straight divided highway with clear sightlines. What federal warning-device layout applies?
Correct answer: Within 10 feet, then about 100 and 200 feet toward approaching traffic
Put the nearest device on the truck's traffic side within 10 feet of its rear, and the others about 100 and 200 feet toward approaching traffic in the occupied lane or shoulder. Obstructed-view situations require additional placement care.
Source: 49 CFR 392.22(b)(2)(iv)-(v), obstructed views and divided or one-way roads; 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 > one-way/divided highway; Figure 2.8; 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 ↗
A car ahead drifts within its lane while its driver looks down repeatedly. How should you react?
Correct answer: Leave extra room and anticipate an unexpected movement
Recognizing distraction in another driver helps you protect your own space.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.9.7, Watch Out for Other Distracted Drivers; printed p. 2-31, physical PDF page 60. ↗
A properly inflated tire’s pressure rises during hot-weather operation. Should you bleed air to its cold-pressure reading?
Correct answer: No, it could become underinflated when it cools
Heat raises pressure; follow cold-inflation specifications rather than vent hot tires.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.14.1, Vehicle Checks > Tires; printed p. 2-36, physical PDF page 65. ↗
One train has passed a crossing with two tracks. What must you check before proceeding?
Correct answer: Whether another train is approaching on either track
A train can conceal another train. Obey warning devices and verify the crossing is clear.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.15.3, Driving Procedures > Double Tracks Require a Double Check; printed p. 2-39, physical PDF page 68. ↗
After a collision, you are uninjured and able to act. What is an immediate priority?
Correct answer: Prevent another collision at the scene
Protect the area, request assistance, and keep emergency access clear.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.20.1, Protect the Area; printed p. 2-46, physical PDF page 75. ↗
For a small fire you are trained to tackle safely, with the correct extinguisher and a clear escape path, where should you aim?
Correct answer: At the base of the fire
The extinguishing agent must reach the burning material rather than only the rising flames.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.21.3, Fire Fighting > Extinguish the Fire; printed p. 2-47, physical PDF page 76. ↗
Your load uses a front-end header board for forward restraint. Why inspect that board before departure?
Correct answer: It helps restrain forward cargo movement toward the cab
A sound front-end structure helps restrain forward cargo movement during a sudden stop. It does not replace the other securement that the load needs.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.3.3, Header Boards; printed p. 3-3, physical PDF page 85. ↗
Before moving a load that exceeds ordinary legal size or weight limits, what arrangements should you check?
Correct answer: Permits, routing limits, and required warnings or escorts
Determine the applicable permit, route, time and warning or escort requirements before departure. Do not assume a warning sign alone authorizes the movement.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 3.4.4, Oversized Loads; printed p. 3-4, physical PDF page 86. ↗
An approaching driver leaves bright lights on. What should you do?
Correct answer: Look toward the right edge reference without staring into the glare
Avoid adding glare or losing sight of your own lane; reduce speed when needed.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.11.5, Night Driving Procedures > Avoid Glare from Oncoming Vehicles; printed p. 2-34, physical PDF page 63. ↗
When should you learn how to fit the chains carried for your drive tires?
Correct answer: Before encountering conditions that require them
Check fit and condition in advance so the equipment can be used correctly when required.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.13.1, Vehicle Checks > Tire Chains; printed p. 2-35, physical PDF page 64. ↗
Does buying a cold medicine without a prescription prove it is safe before commercial driving?
Correct answer: No, it may cause drowsiness or impair driving
Check warnings and appropriate medical advice; over-the-counter availability is not a safety guarantee.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.22.2, Other Drugs: over-the-counter medicines and warning labels; printed p. 2-49, physical PDF page 78. ↗
An interstate truck breaks down on a highway shoulder. Which lights should you switch on immediately?
Correct answer: The four-way emergency flashers
Four-way flashers warn approaching traffic that the vehicle is stopped. If warning devices are required, place them promptly too; flashers are not a substitute.
Source: 49 CFR 392.22(a), immediate hazard flashers for highway or shoulder stops other than necessary traffic stops; 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 > When Parked at the Side of the Road; printed p. 2-17, physical PDF page 46. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=46 ↗
A newer streamlined truck climbed a hill in a relatively high gear. Should you automatically use that same gear to descend?
Correct answer: No, the descent may require a lower gear suited to that truck and grade
Reduced drag and different engine performance can make the old same-gear rule unsuitable. Select the correct low gear before descending.
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. ↗
