The air-system safety relief valve is venting because pressure is excessive. How should the driver treat this finding?
Correct answer: As a fault requiring mechanical attention.
The relief valve protects against excessive pressure; it is not the normal pressure-regulating control. A venting safety valve requires investigation and repair, not disabling.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.6, physical PDF page 76, printed page 5-2. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A driver repeatedly presses and releases the air-brake pedal for no reason while waiting to depart. What can happen?
Correct answer: Air may be used faster than the compressor replaces it.
Brake releases discharge air, and the compressor must replenish it. Unnecessary repeated applications can deplete the available supply.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.7, physical PDF page 76, printed page 5-2. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
In an S-cam drum brake, what is the purpose of the rotating cam at the wheel?
Correct answer: To press the brake shoes outward against the drum.
The S-cam translates linkage movement into shoe contact with the drum. Friction at that contact slows the wheel; the governor and reservoir have different jobs.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.8, physical PDF page 76, printed page 5-2. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
One gauge shows reservoir pressure; an optional second type rises with pedal force. What does that second type indicate?
Correct answer: Pressure being applied to the brakes.
Supply pressure and application pressure are different measurements. An application gauge indicates the pressure used for braking, not the amount stored in the tanks.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.9–5.1.10, physical PDF page 76, printed page 5-2. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A truck has two air-brake circuits but one foot pedal. What does the dual arrangement provide?
Correct answer: Separate air supplies and circuits operated by common controls.
Dual systems separate the air circuits while sharing the driver's controls. Each circuit has its own supply and related components; both must be monitored.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.2, physical PDF page 79, printed page 5-5. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
Using the manual's minimum-pressure guidance for a dual system, one circuit has reached 110 psi but the other is still at 80 psi. Is the truck ready to move?
Correct answer: No; both circuits need at least 100 psi under that guidance.
The cited guidance requires at least 100 psi in both circuits before driving. A healthy reading in one circuit does not substitute for adequate pressure in the other.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.2, physical PDF page 79, printed page 5-5. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
During a trip, one air circuit loses pressure while the other remains charged. What is the appropriate response?
Correct answer: Stop safely and have the air-brake defect corrected.
A dual system may retain enough braking for a controlled stop, but the loss reduces braking capability. The remaining circuit is not permission to continue normal operation.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.2, physical PDF page 79, printed page 5-5. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
An automatic slack adjuster repeatedly shows excessive stroke. What does routinely tightening it by hand fail to address?
Correct answer: The underlying installation, adjuster or brake-component problem.
Repeated manual correction can conceal a defect instead of fixing it. Automatic adjusters still need inspection, and an out-of-adjustment condition needs qualified diagnosis.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.3.2, physical PDF page 80, printed page 5-6. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
The truck's ABS lamp comes on during travel, but there is no separate loss of conventional braking. What does this indicate?
Correct answer: ABS assistance may be impaired even though regular brakes remain.
An ABS fault does not by itself mean total service-brake failure. Report the fault and obtain service promptly; do not interpret the lamp as normal ABS intervention.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.2, physical PDF page 82, printed page 5-8. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A motorcoach with functioning ABS is making an urgent stop on a slippery road and the ABS begins cycling. How should the driver use the pedal?
Correct answer: Maintain the needed steady application and let ABS regulate pressure.
With functioning motorcoach ABS, repeatedly pumping the pedal interferes with the intended control. Maintain the appropriate application and let the system manage impending wheel lock.
Source: FMCSA Motorcoach Brake Systems and Safety Technologies, Important Points about ABS and Related Technologies; functioning motorcoach ABS pedal technique. ↗
Only the tractor has ABS, and the non-ABS trailer starts swinging during braking. What does the manual advise if it can be done safely?
Correct answer: Ease off the brakes enough to regain control.
ABS on the tractor does not guarantee that the trailer's wheels cannot lock. Monitor the whole combination and reduce braking as needed, when safe, to regain control.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.2, physical PDF page 82, printed page 5-8. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
On a long descent, a driver keeps applying the service brakes until they become excessively hot. Why can braking weaken?
Correct answer: Heat can reduce friction and expand the brake drums.
Prolonged brake overuse can reduce effective friction and increase the movement needed to contact an expanded drum. More pedal force is not a reliable cure for overheating.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.5, physical PDF page 83, printed page 5-9. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
During Alabama's modernized vehicle-inspection test, an applicant correctly performs only three of the four air-brake check parts. What is the stated result?
Correct answer: Automatic failure of the vehicle-inspection test.
The modernized supplement requires explanation and demonstration of all four air-brake check parts. A written quiz cannot substitute for performing that check correctly.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2, physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
For the modernized air-gauge and governor-cutoff check, which preparation is correct?
Correct answer: Know the vehicle's cutoff specification; the guide gives roughly 120–140 psi.
The supplement gives an approximate cutoff range and requires the applicant to identify the actual vehicle's setting. A generic memorized number must not replace that specification.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2(1), physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
The vehicle is safely chocked and set up for the modernized applied air-leak test. After a full foot-brake application, when does the one-minute measurement begin?
Correct answer: After the pressure gauge has stabilized.
The applied leak measurement is made with the engine off and the foot brake held, starting after stabilization. The initial application drop is not the timed leakage measurement.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2(2), physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
A single air-braked truck loses 4 psi in the measured minute after the gauge stabilizes during the applied leakage check. How does that compare with the supplement's limit?
Correct answer: It exceeds the 3-psi limit for that single vehicle.
For this applied check, loss above 3 psi in one minute is excessive for a single vehicle. Do not confuse that limit with the combination-vehicle limit or an unapplied test.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2(2), physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
For the standard dual-system example in the manual, with the engine at operating rpm and without oversized-reservoir exceptions, what is the buildup benchmark?
Correct answer: 85 to 100 psi within 45 seconds.
The manual's standard dual-system benchmark is 85–100 psi in 45 seconds. Larger-than-minimum reservoirs may have a different safe buildup time; consult the manufacturer.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.3.3, physical PDF page 81, printed page 5-7. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
The air system cannot build pressure at the rate specified for that truck. What is the appropriate decision?
Correct answer: Do not drive until the cause is corrected.
Inadequate buildup can leave too little air during operation. A departure check should identify and resolve the problem rather than relying on the compressor to catch up on the road.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.3.3, physical PDF page 81, printed page 5-7. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
In the modernized low-speed service-brake check, the vehicle pulls sharply to one side when braking from about 5 mph. What does that suggest?
Correct answer: The brakes may not be functioning correctly.
The low-speed check assesses stopping action and directional pull. Pulling to a side is a fault indication, not a satisfactory result.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.1, physical PDF page 5, printed page 11M-2. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
A truck has the familiar yellow, diamond-shaped push-pull parking-brake knob. Which action applies the parking brakes?
Correct answer: Pull the knob out.
On this control design, pulling applies the parking brakes and pushing releases them. Identify the actual controls on the vehicle; older systems may use other arrangements.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.15, physical PDF page 77, printed page 5-3. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
