Safe Driving Practices

Study questions with answers

7 sample Safe Driving Practices questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.

1. 1. What is the main function of the air compressor?

   Correct answer: It pumps air into the storage tanks

   The compressor's job is to force air into the reservoirs so a supply of compressed air is always available; it is driven off the engine by gears or a belt.

   Source: Connecticut CDL Manual, Section 5.1.1 (Air Compressor)

2. 2. The governor lets the compressor begin pumping again once tank pressure falls to what level?

   Correct answer: Around 100 psi

   The cut-in point sits near 100 psi; once the tanks drop to that pressure the governor allows the compressor to resume pumping.

   Source: Connecticut CDL Manual, Section 5.1.2 (Air Compressor Governor)

3. 3. How do air brakes actually generate their stopping force?

   Correct answer: They rely on compressed air to operate the brakes

   Unlike the hydraulic brakes on cars, an air brake system uses compressed air to make the braking components work, which suits large, heavy vehicles.

   Source: Connecticut CDL Manual, Section 5 (Air Brakes) - overview

4. 4. Air brakes actually combine three separate braking systems. Which set names them correctly?

   Correct answer: The service brakes, the parking brakes, and the emergency brakes

   A vehicle's air brakes are three systems working together: the service brakes for routine stops, the parking brakes for holding it in place, and the emergency brakes for a failure.

   Source: Connecticut CDL Manual, Section 5 (Air Brakes) - overview

5. 5. At roughly what tank pressure does the governor stop the compressor from pumping more air?

   Correct answer: About 125 psi

   When tank pressure climbs to the cut-out level, near 125 psi, the governor halts the compressor's pumping.

   Source: Connecticut CDL Manual, Section 5.1.2 (Air Compressor Governor)

6. 6. If the air compressor has its own supply of oil, what should you do before driving?

   Correct answer: Check the compressor's oil level

   Some compressors are lubricated by their own oil rather than the engine's, so you should verify that oil level before setting out.

   Source: Connecticut CDL Manual, Section 5.1.1 (Air Compressor)

7. 7. Why do the air storage tanks matter if the compressor suddenly quits working?

   Correct answer: They store enough compressed air to allow several brake applications

   The reservoirs keep a reserve of compressed air; even if the compressor fails, there is enough stored to use the brakes several times.

   Source: Connecticut CDL Manual, Section 5.1.3 (Air Storage Tanks)