A damaged exhaust connection is allowing fumes near your truck cab. Why does it need attention before the trip?
Correct answer: Exhaust can enter the cab or sleeper and poison occupants
A leaking exhaust system can carry poisonous fumes into occupied areas. Repair the defect; closing off the sleeper is not protection from fumes.
Source: Washington Commercial Driver Guide, N/10/20; section 2.1.3, physical PDF 31, printed 2-3. ↗
A truck tire has adequate tread depth but its tread is separating from the casing. Can it be used for the planned highway trip?
Correct answer: No; tread separation makes the tire unacceptable for operation
The tire rule separately prohibits tread or sidewall separation. Adequate remaining tread does not cure that defect.
Source: 49 CFR 393.75(a)(2); tread or sidewall separation. ↗
Before reversing under a loading canopy, you cannot judge its clearance from the cab. What should you do?
Correct answer: Stop, get out and check the planned path and overhead space
Check the full backing route, including overhead and side clearance, before moving. If uncertain during the maneuver, stop and check again.
Source: Washington Commercial Driver Guide, N/10/20; section 2.2.4, physical PDF 36, printed 2-8. ↗
You switch to a truck with a different engine and gearbox. How should you decide the proper upshift range?
Correct answer: Use that vehicle's operating instructions and tachometer
Shift ranges depend on the vehicle. Learn the recommended engine-speed or road-speed ranges instead of assuming all trucks share one setting.
Source: Washington Commercial Driver Guide, N/10/20; section 2.3.1, physical PDF 37, printed 2-9. ↗
You checked the mirrors and then signaled a lane change, but have not moved yet. Why check again?
Correct answer: Another vehicle may have entered the space or a blind spot
Traffic positions change quickly. The guide calls for checks before the maneuver, after signaling, as movement begins and after completion.
Source: Washington Commercial Driver Guide, N/10/20; section 2.4.2, physical PDF 39, printed 2-11. ↗
On a straight, level rural divided-highway shoulder, how should you arrange the three required triangles behind a disabled CMV?
Correct answer: One within 10 feet on its traffic side; others about 100 and 200 feet toward approaching traffic
For a divided or one-way road, warn traffic approaching from the rear. The nearest device is on the traffic side; the farther two follow the occupied lane or shoulder.
Source: 49 CFR 392.22(b)(2)(v); unobstructed divided highway, no municipal exception. ↗
On an unlit highway, your stopping distance would extend beyond the area your low beams reveal. What adjustment is needed?
Correct answer: Reduce speed so you can stop within the visible distance
You need enough visible road to stop for a hazard. Driving beyond the effective headlight range leaves too little warning time.
Source: Washington Commercial Driver Guide, N/10/20; section 2.11.4, physical PDF 54, printed 2-26. ↗
In good conditions at 35 mph, what starting gap follows the guide's one-second-per-10-feet rule for a 40-foot truck?
Correct answer: At least 4 seconds
Forty feet gives four seconds at this speed. Add more space for poor traction, visibility or other hazards; this is a baseline safety guideline.
Source: Washington Commercial Driver Guide, N/10/20; section 2.7.1, physical PDF 44, printed 2-16. ↗
Your low trailer approaches a sharply raised railroad crossing. What must you consider before entering?
Correct answer: Whether its underside could hang up before it clears the tracks
Low ground clearance and a steep crossing profile can trap a trailer on the rails. Do not enter unless the vehicle can clear the crossing safely.
Source: Washington Commercial Driver Guide, N/10/20; section 2.7.5, physical PDF 45, printed 2-17. ↗
A car entering an exit lane suddenly brakes and hesitates. What possible action should you prepare for?
Correct answer: It may return unexpectedly to the through lane
Hesitation near an exit can precede a sudden change of direction. Create time and space before the developing hazard becomes an emergency.
Source: Washington Commercial Driver Guide, N/10/20; section 2.8.1, physical PDF 46, printed 2-18. ↗
While seeking a safe place to stop in fog, which headlights should you use?
Correct answer: Low beams
Low beams reduce reflected glare and help others see the truck. Reduce speed before visibility worsens and leave the roadway for a safe stopping place when needed.
Source: Washington Commercial Driver Guide, N/10/20; section 2.12, physical PDF 55, printed 2-27. ↗
The engine coolant is very hot. What is the safe approach to a radiator cap that is part of the pressurized system?
Correct answer: Leave it closed until the system has cooled
Hot pressurized coolant and steam can cause severe burns. Shutting the engine off does not instantly cool or depressurize the system.
Source: Washington Commercial Driver Guide, N/10/20; section 2.14.1, physical PDF 57, printed 2-29. ↗
On a long descent, repeated heavy service-brake use produces less slowing despite more pedal pressure. What may be happening?
Correct answer: The brakes are overheating and fading
Excess heat can reduce braking effectiveness. Proper gear and speed selection help avoid relying too heavily on the service brakes.
Source: Washington Commercial Driver Guide, N/10/20; section 2.16.3, physical PDF 60, printed 2-32. ↗
You must make an emergency stop in a straight truck with functioning ABS on every axle. Which action does the guide permit?
Correct answer: Fully apply the brakes while maintaining control
The guide expressly allows full application for an emergency stop with working ABS on all axles. This is not the same as advice for a combination with ABS on only part of it.
Source: Washington Commercial Driver Guide, N/10/20; section 2.18.6, physical PDF 64, printed 2-36. ↗
After stopping safely, you suspect a fire under the truck's hood. Should you open it to inspect the flames?
Correct answer: No; opening it can feed the fire and make it grow
Keep the hood closed, shut off the engine after stopping, evacuate and call emergency services. Do not approach or reopen the burning vehicle.
Source: US Fire Administration, Vehicle Fire Safety; if your vehicle catches fire. ↗
You start a trip with accessible cargo in an interstate truck; no inspection exception applies. When must you first recheck its securement on the road?
Correct answer: Within the first 50 miles
Inspect within the first 50 miles and make needed adjustments. The later reinspection intervals do not replace this initial check.
Source: 49 CFR 392.9(b)(2), (b)(4); initial check with sealed/impracticable exceptions excluded. ↗
A loaded truck is within its overall weight limit, but cargo is concentrated over one axle. What must be checked?
Correct answer: Individual axle loading as well as the total vehicle weight
An acceptable total does not prove acceptable axle loading or balance. Load distribution affects both equipment limits and handling.
Source: Washington Commercial Driver Guide, N/10/20; section 3.2.4, physical PDF 73, printed 3-2. ↗
You secure shaped blocks snugly against a crate and fasten them to the deck. What is their main purpose?
Correct answer: Prevent the crate from sliding along the load deck
Blocking restrains movement at the cargo's sides, front or rear. Its installation and strength must suit the load; other applicable securement requirements still matter.
Source: Washington Commercial Driver Guide, N/10/20; section 3.3.1, physical PDF 73, printed 3-2. ↗
A 12-foot article is not blocked against forward movement. Under the general tiedown-count rule, how many are needed at minimum?
Correct answer: Three tiedowns
For an unblocked article longer than ten feet, use two for the first ten feet plus one for the remaining fraction. This is the count minimum, with strength and other applicable requirements separate.
Source: 49 CFR 393.110(b)(3); unblocked 12-foot article, no special-method exception. ↗
A tarp covers freight on a flatbed. What still needs to be established before driving?
Correct answer: That the cargo itself is properly secured against movement
A cover can protect against weather or spillage, but it does not automatically provide the restraint needed to secure the cargo. Secure the load and the cover.
Source: Washington Commercial Driver Guide, N/10/20; section 3.3.4, physical PDF 74, printed 3-3. ↗
