On a vehicle without ABS, what defines controlled braking during an emergency stop?
Correct answer: Brake as hard as possible without locking the wheels
For controlled braking, brake firmly without locking the wheels and keep steering movements small. If wheels lock or a larger steering correction is needed, release the brakes and reapply as soon as possible. This question concerns a vehicle without ABS.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.4.3 Emergency Stops, Controlled Braking, printed page 5-8 (physical PDF page 86) ↗
Which extra factor is part of total stopping distance for an air-brake vehicle?
Correct answer: Brake lag distance
Air needs time to reach the brakes, adding brake lag to perception, reaction, and braking distances.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.4.4 Stopping Distance, printed page 5-8 (physical PDF page 86) ↗
At 55 mph on dry pavement, approximately how much distance can air-brake lag add?
Correct answer: 32 feet
The handbook estimates about 32 feet of brake-lag distance at 55 mph.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.4.4 Stopping Distance, printed page 5-8 (physical PDF page 86) ↗
What is a primary cause of brake fade on a long downgrade?
Correct answer: Excessive service-brake use and heat
Overuse creates heat that reduces lining friction and expands drums, weakening braking.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.4.5 Brake Fading or Failure, printed page 5-9 (physical PDF page 87) ↗
What should a driver do when the low-air warning activates on the road?
Correct answer: Stop and park safely as soon as possible
A warning may indicate a leak; stop safely before pressure falls far enough for spring brakes to apply.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.4.7 Low Air Pressure, printed page 5-9 (physical PDF page 87) ↗
Before moving a vehicle with a dual air brake system, what should you confirm on both pressure gauges?
Correct answer: Both systems have reached at least 100 psi
The handbook instructs drivers to allow pressure to build to at least 100 psi in both systems before driving. Check both gauges rather than assuming one charged circuit means the other is ready.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.2 Dual Air Brake, printed page 5-5 (physical PDF page 83) ↗
One circuit of a dual air brake system loses pressure while you are driving. Why must you stop safely and obtain repairs?
Correct answer: The remaining circuit does not provide normal braking at all wheels
A failure in one circuit can leave part of the vehicle without working service brakes. Stopping distance increases, so bring the vehicle to a safe stop and have the system repaired before continuing.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.2 Dual Air Brake, printed page 5-5 (physical PDF page 83) ↗
What should you inspect on a belt-driven air compressor during the engine-compartment check?
Correct answer: Belt condition and tightness
A loose or damaged drive belt can prevent correct air supply. Section 5.3.1 calls for checking the belt condition and tightness.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.3.1 Check Air Compressor Drive Belt, printed page 5-6 (physical PDF page 84) ↗
An automatic slack adjuster repeatedly has excessive stroke. What is the appropriate response?
Correct answer: Have the underlying brake problem diagnosed and repaired
Excessive stroke with an automatic adjuster can indicate a mechanical problem. Routine manual adjustment can conceal the defect and is not a substitute for qualified repair following the manufacturer’s procedures.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.3.2 Automatic Slack Adjusters, printed page 5-6 (physical PDF page 84) ↗
After its normal startup check, an ABS warning lamp comes on while the vehicle is moving. What does this suggest?
Correct answer: A possible ABS malfunction that needs attention
An ABS malfunction lamp that remains on after the appropriate check or comes on during travel can indicate an ABS fault. Normal braking remains, but the fault needs service; follow the vehicle-specific lamp-check procedure.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.16 Antilock Braking Systems, printed page 5-4 (physical PDF page 82) ↗
Which benefit should you expect from ABS during hard braking?
Correct answer: Reduced wheel locking, helping you retain vehicle control
ABS helps prevent wheel lock during hard braking. It supports control but does not necessarily shorten stopping distance and does not replace careful speed or following-distance choices.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.16 Antilock Braking Systems, printed page 5-4 (physical PDF page 82) ↗
Brakes are very wet and temperatures are freezing. What parking precaution does the Florida air-brake chapter describe?
Correct answer: Use wheel chocks on a level surface instead of applying wet parking brakes
Very wet parking brakes may freeze in place. Secure the vehicle with wheel chocks on level ground; never leave it able to roll.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.4.8 Parking Brakes, printed page 5-9 (physical PDF page 87) ↗
During a brake inspection, you find oil or grease on a brake lining. How should this be treated?
Correct answer: As a brake defect that needs correction
Brake linings should not be loose or contaminated with oil or grease. Normal air pressure does not make a defective friction surface safe; the defect needs correction.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.3.2 Check Brake Drums (or Discs), Linings, and Hoses, printed page 5-6 (physical PDF page 84) ↗
An older truck has a manual front brake limiting valve marked NORMAL and SLIPPERY. Which setting normally preserves full front braking?
Correct answer: NORMAL
The manual limiting valve reduces front brake pressure in the SLIPPERY position and can reduce stopping ability. The handbook says to leave this type of control in NORMAL for normal stopping power.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.13 Front Brake Limiting Valve, printed page 5-3 (physical PDF page 81) ↗
What should you look for when inspecting the flexible air hoses connected to brake chambers?
Correct answer: Damage or wear caused by rubbing
Inspect brake hoses for damage and wear from rubbing. A hose problem can lead to air loss; do not dismiss it because pressure is currently normal or disconnect a pressurized line as a routine inspection step.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.3.2 Check Brake Drums (or Discs), Linings, and Hoses, printed page 5-6 (physical PDF page 84) ↗
Which three functions make up the air-brake system described in the handbook?
Correct answer: Service, parking, and emergency braking
The functions serve normal stops, parking, and brake-system failures.
Source: Florida Commercial Driver's License Manual, July 2022, Section 5 introduction, three braking systems, printed page 5-1 (physical PDF page 79) ↗
In normal service braking, pressing the pedal farther does what?
Correct answer: Sends greater application pressure to the brakes
Pedal force controls service-brake application pressure.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.7 The Brake Pedal, printed page 5-2 (physical PDF page 80) ↗
An air compressor has its own oil supply rather than engine lubrication. What should you check before driving?
Correct answer: Its oil level
A separately lubricated compressor needs its own oil check.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.1 Air Compressor, printed page 5-1 (physical PDF page 79) ↗
Does an alcohol evaporator eliminate the need to drain manually drained air tanks?
Correct answer: No, tank drainage is still required
The evaporator helps reduce freezing risk; it does not remove accumulated water and oil.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.5 Alcohol Evaporator, printed page 5-2 (physical PDF page 80) ↗
The air-system safety valve releases air. What does this indicate?
Correct answer: A fault requiring mechanical attention
The safety valve is a pressure safeguard, not the ordinary compressor control.
Source: Florida Commercial Driver's License Manual, July 2022, section 5.1.6 Safety Valve, printed page 5-2 (physical PDF page 80) ↗
