A bus subject to federal equipment rules has a retreaded front tire with deep, undamaged tread. Is the tread depth enough to make that installation acceptable?
Correct answer: No. Retreaded tires are prohibited on the front wheels of the bus.
Federal rules prohibit regrooved, recapped and retreaded tires on the front wheels of a bus. Adequate tread depth does not remove that position-specific restriction; this is not a ban on every rear tire.
Source: 49 CFR 393.75(d); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. Also Colorado CDL Manual (06/15/23), page 16. ↗
You find grease on a truck's brake lining during inspection. What is the appropriate response?
Correct answer: Have the brake defect corrected before starting the trip.
Oil, grease or brake fluid on friction material is a brake defect. A sound drum does not make contaminated lining acceptable, and the parking brake is not a substitute for a safe service-brake system.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.1.3 Bad Brake Drums or Shoes; physical PDF page 17 (printed 17); reviewed September 14, 2026. ↗
A driver checks the same vehicle daily. What approach best reduces overlooked inspection items?
Correct answer: Use a consistent inspection routine on each trip.
A repeatable method helps prevent omissions. Familiarity with a vehicle or a trouble-free previous trip does not show that its current condition is safe.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.1.5 Method of Inspection; physical PDF page 18 (printed 18); reviewed September 14, 2026. ↗
In a safe low-speed brake check, the truck pulls noticeably to one side. What is the best conclusion?
Correct answer: A brake or related safety problem needs investigation.
Pulling, unusual pedal feel or delayed stopping action can signal trouble. Resolve an unsafe condition before the trip instead of treating steering compensation as a repair.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.1.5 Test Service Brake Stopping Action; physical PDF page 22 (printed 22); reviewed September 14, 2026. ↗
A manually shifted truck is stopped uphill. When should the driver release a parking brake being used to prevent rollback?
Correct answer: When enough engine power is applied to prevent rolling backward.
Coordinate the clutch, power and brakes so the vehicle does not roll backward into someone behind it. When using the parking brake for this purpose, release it after sufficient power is available.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.2.1 Accelerating; physical PDF page 23 (printed 23); reviewed September 14, 2026. ↗
Why does the handbook recommend the lowest reverse gear and very slow backing?
Correct answer: They leave more time to correct steering and stop.
Low reversing speed helps the driver correct small steering errors and stop promptly. It does not remove blind spots or replace an outside check.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.2.4 Back Slowly; physical PDF page 23 (printed 23); reviewed September 14, 2026. ↗
A driver changes to a truck with a different engine and gearbox. How should the driver establish suitable shift points?
Correct answer: Learn that vehicle's operating ranges and use its gauges.
Shift points depend on the vehicle. Use the manufacturer's operating information and the tachometer or known road-speed ranges; some systems use progressive shifting rather than one fixed RPM for every gear.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.3.1 Knowing When to Shift Up; physical PDF page 24 (printed 24); reviewed September 14, 2026. ↗
Which scanning pattern matches the handbook's guidance for a commercial driver?
Correct answer: Look at least 12 to 15 seconds ahead while also checking nearer hazards.
The 12-to-15-second look-ahead guidance gives time to plan. It is not a following-gap rule or a reason to stare at one point: shift attention between near, far and surrounding traffic.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.4.1 Seeing Ahead; physical PDF page 25 (printed 25); reviewed September 14, 2026. ↗
A truck driver checked the adjacent lane, then turned on the signal. Why check again before and during the lane change?
Correct answer: Another vehicle may have entered a blind area since the first check.
Conditions change between an initial check and a maneuver. The handbook calls for repeated checks before, after signaling, as the change begins and after completion; signaling does not create a guaranteed gap.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.4.2 Lane Changes; physical PDF page 25 (printed 25); reviewed September 14, 2026. ↗
A driver behind your truck seems hesitant to overtake. Should you wave them past as a promise that the road is clear?
Correct answer: No. Let that driver judge and perform their own safe pass.
Do not signal that it is safe for another driver to pass. Your view and their assessment may differ, and a wave can encourage a maneuver whose safety you cannot guarantee.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.5.1 Don't Direct Traffic; physical PDF page 26 (printed 26); reviewed September 14, 2026. ↗
On a straight rural divided highway, an interstate truck is disabled on the shoulder with clear sight lines. Which triangle arrangement matches the federal rule?
Correct answer: One within 10 feet at the traffic side of the rear; others 100 and 200 feet toward approaching traffic.
For a divided or one-way highway, the two farther devices go 100 and 200 feet toward approaching traffic, centered in the occupied lane or shoulder. The nearest goes at the traffic side within 10 feet of the rear. An obstruction to sight can require adjusted placement.
Source: 49 CFR 392.22(b)(2)(v); eCFR title 49 displayed current through September 10, 2026; reviewed September 14, 2026. Also Colorado CDL Manual (06/15/23), page 27. ↗
A driver estimates stopping space using only the distance traveled after braking starts. What has been left out of the handbook's basic total?
Correct answer: The distance traveled while perceiving the hazard and reacting.
The basic total includes perception, reaction and braking distances. The vehicle travels before the driver applies the brakes as well as during braking. System-specific delays, such as air-brake lag, also matter in applicable vehicles.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.6.1 Stopping Distance; physical PDF page 27 (printed 27); reviewed September 14, 2026. ↗
It is below freezing and a shaded stretch of road looks wet rather than snowy. What should the driver consider?
Correct answer: The apparent wetness may be a thin layer of clear ice.
Clear ice can show the pavement beneath it and look like water. Below-freezing temperatures and shaded areas are reasons for extra caution, not reasons to rule out ice.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.6.2 Identifying Slippery Surfaces; physical PDF page 28 (printed 28); reviewed September 14, 2026. ↗
Using the handbook's basic following-gap guideline in good conditions, what gap should a 40-foot truck leave at 35 mph?
Correct answer: At least 4 seconds.
The guideline is one second per 10 feet of vehicle length below 40 mph: 40 divided by 10 gives four seconds. This is a starting guideline, not a guarantee for poor weather or other hazards.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.7.1 Space Ahead; Figure 2.12; physical PDF page 30 (printed 30); reviewed September 14, 2026. ↗
An empty, high-sided truck emerges from a sheltered tunnel into strong crosswinds. What deserves extra attention?
Correct answer: Lateral movement and clearance from vehicles alongside.
Strong winds can push a vehicle sideways, especially a light one, and exposure can change suddenly outside a tunnel. Maintain control and side space instead of traveling unnecessarily alongside other vehicles.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.7.3 Strong Winds; physical PDF page 31 (printed 31); reviewed September 14, 2026. ↗
A driver turns a long truck left too early at an intersection. What can the rear portion do?
Correct answer: Cut inside the front path and strike a vehicle or object on the left.
The rear wheels of a long vehicle follow an inside path in a turn. Starting the left turn too early can bring the vehicle's left side into nearby traffic or objects; allow space for the whole vehicle.
Source: Colorado Commercial Driver License Manual (06/15/23), Section 2; 2.7.6 Left Turns; physical PDF page 31 (printed 31); reviewed September 14, 2026. ↗
