A mechanic has repaired a defect on an interstate commercial vehicle. Before driving, who must still be satisfied that its required equipment works safely?
Correct answer: The driver
The driver's before-driving responsibility remains even when a mechanic has carried out repairs. Do not operate with an unsafe defect.
Source: 49 CFR 392.7(a), driver satisfaction with required equipment before operation; 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), 2.1.5, Seven-step Inspection Method > Step 7: unsafe defects; printed p. 2-10, physical PDF page 39. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=39 ↗
Which items should a commercial driver monitor during a trip for signs of trouble?
Correct answer: Gauges, sight, sound, smell, and feel
Trip inspection includes watching gauges and using the senses to detect developing problems.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.1.2, Types of Vehicle Inspection > During a Trip; printed p. 2-2, physical PDF page 31. ↗
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 ↗
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 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. ↗
Why is excessive steering-wheel play a serious inspection defect?
Correct answer: It can make the vehicle difficult to steer
Excessive play can prevent precise steering control and must be investigated.
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. ↗
Which is a federal warning-equipment option for an interstate commercial vehicle?
Correct answer: Three red reflective warning triangles
Three approved bidirectional reflective triangles are a federal warning-equipment option. They must meet the applicable equipment standard; ordinary lights do not replace them.
Source: 49 CFR 393.95(f)(1), three conforming bidirectional emergency reflective triangles; 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), 2.1.5, Seven-step Inspection Method > Check Emergency Equipment; printed p. 2-7, physical PDF page 36. https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf#page=36 ↗
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. ↗
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. ↗
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. ↗
How should speed be chosen when fog or darkness limits the view ahead?
Correct answer: So the vehicle can stop within the visible distance
A driver must always be able to stop within the distance that can be seen clearly.
Source: Pennsylvania Commercial Driver's Manual PUB 223 (6-26), 2.6.4, Speed and Distance Ahead; printed p. 2-20, physical PDF page 49. ↗
Under the handbook length rule below 40 mph, what is the minimum following time for a 50-foot commercial vehicle?
Correct answer: 5 seconds
The basic minimum is one second per 10 feet of vehicle length: five seconds for 50 feet. Leave more space when road, traffic, or weather conditions require it.
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. ↗
