Georgia CDL Permit Test - Knowledge Test Class B

Hydroplaning is a phenomenon during which a vehicle's tires lose traction with the road surface and begin to glide along on water on the road. There does not have to be a large amount of water on the road for this to occur.

The purpose of an Anti-Lock Braking System (ABS) is to prevent a vehicle's wheels from locking up when the driver brakes hard on a slippery surface.

Air brake system tanks must contain drain valves. These valves are used to drain accumulated oil and water from the tanks and may be either manually or automatically operated.

An alcohol evaporator can help prevent ice from building up in an air brake system. In cold weather, the evaporator should be checked and refilled every day.

Speeding up too quickly on a road with poor traction could cause a driver to lose control of their vehicle. In conditions that cause poor traction, a driver should accelerate especially smoothly and gradually.

A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

If you fail a required knowledge test, you must wait a minimum of two days before retaking the test. If you have passed knowledge tests for other endorsements, you may still take the skills tests required for those endorsements.