Air Brake Test Air Brake Driving Techniques & Vehicle Control 2

Question 1

What is the recommended following distance for a truck with air brakes at highway speeds?

Accepted Answer

One second for every 10 feet of vehicle length

Answer

The CDL standard is one second per 10 feet of vehicle length, plus extra time at speeds over 40 mph.

Question 2

What is 'air brake lag time'?

Accepted Answer

The delay between pressing the brake pedal and the brakes actually applying force

Answer

Air brake lag is typically about one-half second, during which the vehicle continues moving at full speed before braking begins.

Question 3

Which three components combine to make up the total stopping distance for a truck with air brakes?

Accepted Answer

Perception/reaction distance + brake lag distance + actual braking distance

Answer

Total stopping distance is the sum of how far the truck travels during perception/reaction, during brake lag, and during actual braking.

Question 4

At 55 mph on dry pavement, approximately how many feet does a fully loaded large truck typically need to stop?

Accepted Answer

About 300 feet or more

Answer

A fully loaded truck at 55 mph on dry pavement can require 300 feet or more to stop safely when all factors are included.

Question 5

Why can a fully loaded truck sometimes require more stopping distance than an empty truck?

Accepted Answer

Greater mass means more kinetic energy must be dissipated during braking

Answer

Greater vehicle mass means significantly more kinetic energy at the same speed, requiring more braking force and distance to stop.

Air Brake Practice Test