You are checking a truck whose air compressor has its own oil supply. Which extra check belongs in the pre-trip inspection?
Correct answer: Check that compressor's oil level.
A separately lubricated compressor needs its own oil-level check. Engine lubrication does not automatically cover every compressor design.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.1, physical PDF page 75, printed page 5-1. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
During a stationary check, reservoir pressure falls to the manufacturer's cut-in setting. What should a functioning governor allow?
Correct answer: The compressor to resume building reservoir pressure.
Cut-in is the point at which the compressor resumes charging the air reservoirs. Check the actual cut-in and cutoff settings specified for that vehicle.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.2, physical PDF page 75, printed page 5-1. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
Water has accumulated in an air reservoir before a freezing night. What brake-system risk does this create?
Correct answer: Ice can obstruct components and interfere with braking.
Moisture carried in compressed air can collect in the tanks and freeze. Removing contamination helps prevent brake-system failures in cold conditions.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.4, physical PDF page 75, printed page 5-1. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A truck has manual tank drains and no automatic drainage. When should the driver complete the regular draining task described in the manual?
Correct answer: At the end of each driving day.
The manual's daily draining instruction applies to tanks that require manual drainage. Water and oil can accumulate in warm weather too.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.4, physical PDF page 75, printed page 5-1. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
On a spring-brake-equipped truck, what normally keeps the powerful parking-brake springs from applying while driving?
Correct answer: Sufficient air pressure holding the springs back.
Air pressure holds the spring brakes released. Loss or release of that air allows the mechanical springs to apply the brakes.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.14, physical PDF page 77, printed page 5-3. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
The wheel brakes on a spring-brake truck are out of adjustment. Which braking capability can be affected?
Correct answer: Both normal braking and spring-brake holding power.
Adequate air pressure alone cannot correct a mechanical adjustment defect. The same wheel-brake condition can undermine service and spring-brake effectiveness.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.14, physical PDF page 77, printed page 5-3. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A truck lacks a reliable anti-compounding feature. Why should its driver avoid a hard foot-brake application while the spring brakes are applied?
Correct answer: The combined forces can damage the brake mechanism.
Service pressure and spring force can act together. Not every system prevents this compounding, so the driver must use the controls as specified for the vehicle.
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. ↗
A bus has a separate emergency reservoir that can briefly release applied spring brakes after main-air loss. What should the driver remember?
Correct answer: That reserve permits only a limited number of releases.
A reserve air supply is finite and must be managed carefully during an emergency move. It is not a repair or an unlimited replacement for the main air system.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.15, physical PDF page 78, printed page 5-4. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
During a walk-around, you find oil-soaked brake lining and a hose worn by rubbing. What is the appropriate assessment?
Correct answer: These are brake defects that must be addressed.
Reservoir pressure cannot prove that friction material and hoses are sound. Contaminated lining and damaged air hoses require attention before relying on the brakes.
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. ↗
While using controlled braking in a vehicle without ABS, the wheels lock. What is the correction described for that method?
Correct answer: Release the brakes, then reapply as soon as control permits.
Controlled braking aims to avoid wheel lock while preserving direction. A lockup calls for release and timely reapplication; this is not an instruction to pump functioning ABS.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.3, physical PDF page 82, printed page 5-8. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A stopping-distance estimate includes perception, reaction and wheel-braking distance. Which additional allowance is important for an air-braked vehicle?
Correct answer: Distance traveled while air pressure reaches and operates the brakes.
Air-brake response includes a delay between pedal application and braking action. That travel distance adds to the other parts of the stopping-distance estimate.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.4, physical PDF page 82, printed page 5-8. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A driver proposes reducing following space because the truck has ABS. Which explanation best corrects that decision?
Correct answer: ABS helps control wheel lock but does not guarantee a shorter stop.
The main ABS benefit is wheel-lock control during braking. It does not eliminate reaction time, traction limits or the need for adequate following space.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.1.16, physical PDF page 78, printed page 5-4. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
Several wheel brakes are out of adjustment while the others work correctly. Why does this also threaten the working brakes on a descent?
Correct answer: The working brakes may carry extra load, overheat and fade.
If some brakes do less work, the others must absorb more of the vehicle's braking demand. This can overheat them and reduce overall control.
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. ↗
Before a long, steep downgrade, how should the driver plan to control an air-braked truck's speed?
Correct answer: Select an appropriate low gear and use service braking as a supplement.
The engine's braking effect in a suitable gear helps control the descent. The service brakes supplement it; they should not carry the entire speed-control task.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.6, physical PDF page 83, printed page 5-9. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
A driver has selected an appropriate low gear and a safe downhill speed of 35 mph. In the manual's described braking cycle, about when is the brake application released?
Correct answer: After slowing to about 30 mph.
The described cycle reduces speed by about 5 mph below the selected safe speed before release. This example is a technique illustration, not a universal safe speed for a hill.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.6, physical PDF page 83, printed page 5-9. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
At a safe, level stopping place, the brakes are very hot after a descent. What precaution does the manual describe before using the parking brakes?
Correct answer: Secure the vehicle with wheel chocks and let the brakes cool.
The manual warns about applying parking brakes to very hot brakes. Its stated alternative is wheel chocks on a level surface while cooling, not leaving the vehicle free to roll.
Source: ALEA Commercial Driver License Manual, July 2017 section text, current ALEA catalog PDF; section 5.4.8, physical PDF page 83, printed page 5-9. Equipment and driving knowledge; modernized inspection procedures are cited separately. ↗
An air-braked tractor-trailer loses 5 psi in the stabilized one-minute applied leakage check. What is the correct assessment?
Correct answer: It exceeds the 4-psi limit for that combination.
The modernized applied check allows no more than 4 psi loss in one minute for a combination. A 5-psi loss exceeds that criterion.
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 Alabama's modernized air-warning check, which criterion should the applicant use?
Correct answer: Activation before pressure falls below 55 psi, or the manufacturer's specified level.
This is the cited Alabama test procedure, which expressly includes the manufacturer's specification. It is not a claim that 55 psi is the universal design requirement for every air-braked vehicle.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2(3), physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
For a vehicle using conventional pop-out valves in the modernized emergency-brake check, what range does the guide state?
Correct answer: 20–45 psi, with the actual vehicle specification identified.
The emergency-application check is distinct from governor cutoff and the low-air warning. The guide states 20–45 psi and requires knowledge of the actual vehicle system.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2(4), physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
The test vehicle's manufacturer specifies a system whose valves do not pop out in the ordinary way. What should the applicant do?
Correct answer: Explain and demonstrate the manufacturer's specified procedure and system behavior.
The supplement recognizes different systems, including non-pop-out and backup-air arrangements. Applicants must know and explain the procedure applicable to their test vehicle.
Source: ALEA CDL Modernized Supplement, September 9, 2022 text, adopted July 1, 2025; section 11M.1.2(4), physical PDF page 6, printed page 11M-3. Modernized vehicle-inspection procedure; use the test vehicle manufacturer specifications. ↗
