Traffic Laws

Study questions with answers

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

1. 1. What braking equipment must every truck, truck tractor, and bus carry?

   Correct answer: Emergency and parking brakes held on by mechanical force

   These vehicles must have emergency and parking brakes, and since air can eventually leak away, those brakes are held on by mechanical force, usually by spring brakes.

   Source: Section 5.1.14 - Spring Brakes

2. 2. Truck tractors with air brakes built on or after which date are required to have antilock brakes?

   Correct answer: March 1, 1997

   Air brake truck tractors manufactured on or after March 1, 1997 must carry ABS; other air brake vehicles are covered from March 1, 1998.

   Source: Section 5.1.16 - Antilock Braking Systems (ABS)

3. 3. The driver-operated front brake limiting valve was fitted on some vehicles built during which era?

   Correct answer: Before 1975

   A cab-controlled front brake limiting valve, with a switch marked 'normal' and 'slippery,' appeared on some older vehicles made before 1975.

   Source: Section 5.1.13 - Front Brake Limiting Valve

4. 4. At roughly what pressure is the air system's safety relief valve usually set to open?

   Correct answer: 150 psi

   The safety relief valve, mounted in the first tank the compressor feeds, guards against too much pressure and is normally set to open near 150 psi.

   Source: Section 5.1.6 - Safety Valve

5. 5. At roughly what pressure does the governor's cut-in point let the compressor start pumping again?

   Correct answer: Around 100 psi

   When tank pressure falls to the cut-in level, about 100 psi, the governor lets the compressor resume pumping.

   Source: Section 5.1.2 - Air Compressor Governor

6. 6. At about what tank pressure does the governor reach its cut-out point and stop the compressor from pumping?

   Correct answer: Around 125 psi

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

   Source: Section 5.1.2 - Air Compressor Governor

7. 7. Which vehicles are required to carry a low air pressure warning signal?

   Correct answer: Every vehicle equipped with air brakes

   A low air pressure warning signal is mandatory on any vehicle that uses air brakes.

   Source: Section 5.1.11 - Low Air Pressure Warning