Tennessee CDL — Air Brakes Practice Test 10

1.With the engine off and the brakes released, what is the maximum acceptable air leakage for a combination vehicle over one minute?

Less than five psi in one minuteLess than eight psi in one minuteLess than one psi in one minuteLess than three psi in one minute

2.While driving, the low-pressure warning suddenly comes on. What is your safest move?

Speed up to reach your destination before pressure runs outPump the brakes hard to keep pressure upStop and safely park as soon as possibleSet the parking brake while still moving fast

3.How does the stop light switch warn drivers behind you that you are braking?

It sounds a horn as the pedal movesIt drops a wig wag arm behind the cabAn air-operated electric switch turns on the brake lightsIt flashes the low pressure warning light

4.An air brake setup is really a combination of three braking systems. Which trio is correct?

Service, parking, and emergency brakesPrimary, secondary, and backup circuitsHydraulic, mechanical, and electric brakesFoot, hand, and drum brakes

5.What is a dual air brake system?

A single system with two backup compressorsA system that uses both air and hydraulic fluidTwo brake pedals feeding one air tankTwo separate air systems that share one set of brake controls

6.How is the "stab braking" method performed in an emergency?

Hold steady, light pressure the entire timeApply the parking brake in short burstsApply fully, release when wheels lock, then apply fully again once they rollSteer hard while holding the wheels locked

7.Why are spring brakes held off by air pressure while you drive rather than held on by air?

Because springs are cheaper than air tanksBecause the governor cannot supply air when parkedBecause air pressure can leak away, so mechanical force must hold the brakes onBecause the compressor only runs while moving

8.On a long, steep downgrade, the braking effect of the service brakes should be treated as what?

The only thing you need to control speedOnly a supplement to the engine's braking effectA replacement for gearing downSomething to avoid using entirely on hills

9.When should you NOT use the parking brakes to hold the vehicle?

Whenever the vehicle is fully loadedAny time you park on level groundWhen the brakes are very hot or very wet in freezing temperaturesWhen the engine is still running

10.Which factors are added together to make up the total stopping distance for an air brake vehicle?

Perception and braking distance onlyReaction distance and tank pressurePerception, reaction, brake lag, and braking distanceBrake lag and governor cut-out time only