Air Brake Test Stopping Distance & Brake Performance

Question 1

What are the three main components that make up total stopping distance for a vehicle with air brakes?

Accepted Answer

Perception distance, reaction distance, and braking distance

Answer

Brake lag, skid distance, and deceleration distance

Answer

Air pressure buildup, brake application, and wheel lockup

Answer

Driver alertness, road friction, and vehicle weight

Question 2

Approximately how long is the brake lag time for air brakes compared to hydraulic brakes?

Accepted Answer

Air brakes lag about 0.4 seconds vs. 0.1 seconds for hydraulic brakes

Answer

Air brakes lag about 0.1 seconds vs. 0.4 seconds for hydraulic brakes

Answer

Both systems have the same lag time of about 0.2 seconds

Answer

Air brakes lag about 1.0 second vs. 0.5 seconds for hydraulic brakes

Question 3

At 55 mph on dry pavement, approximately how many feet of additional stopping distance does air brake lag add compared to the moment you press the brake pedal?

Accepted Answer

About 32 feet

Answer

About 10 feet

Answer

About 60 feet

Answer

About 100 feet

Question 4

A fully loaded truck traveling at 55 mph on dry pavement requires approximately how many feet to come to a complete stop?

Accepted Answer

About 335 feet

Answer

About 150 feet

Answer

About 500 feet

Answer

About 200 feet

Question 5

How does vehicle weight affect stopping distance for air-braked vehicles?

Accepted Answer

Empty trucks often take longer to stop than fully loaded trucks due to reduced traction

Answer

Heavier trucks always stop in a shorter distance than lighter trucks

Answer

Vehicle weight has no significant effect on stopping distance

Answer

Loaded trucks always require exactly twice the stopping distance of empty trucks

Question 6

Which factor has the GREATEST impact on braking distance when descending a steep grade?

Accepted Answer

The grade itself increases the speed and force needed to stop, dramatically lengthening stopping distance

Answer

Downhill grades reduce stopping distance because gravity assists braking

Answer

Only the length of the hill matters, not the steepness of the grade

Answer

Stopping distance on a downgrade is the same as on flat ground if brakes are properly adjusted

Question 7

If you double your speed from 20 mph to 40 mph, by approximately how much does your braking distance increase?

Accepted Answer

Braking distance increases approximately four times

Answer

Braking distance doubles

Answer

Braking distance triples

Answer

Braking distance increases by one and a half times