An Anti-Lock Braking System (ABS) helps to provide additional control during hard braking, but does not necessarily shorten a vehicle's stopping distance.

Because air takes time to flow through the air lines to the brakes, air brakes cannot begin working instantly. There is often a brake lag of at least one-half of a second between the moment the brake pedal is pressed and the moment the brakes begin to work.

Spring brakes do not work on all axles. If your vehicle's spring brakes activate due to low pressure in an air brake system, your vehicle will need a longer distance to stop than usual, especially if you are carrying a heavy load.

When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 psi in one minute. If the air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

On long and/or steep downgrades, you should primarily use engine braking to control the speed of your vehicle. Use your brakes only as a supplement to this effect.

If equipped, ABS is in addition to a vehicle's normal braking system and does not increase or decrease the braking power of any other system. ABS only activates when a vehicle's wheels are about to lock.

If you need to make an emergency stop, you can use either the controlled braking method or the stab braking method. It's important to brake in a way that keeps your vehicle in a straight line but will still allow you to turn if necessary.

Any vehicle with air brakes must be equipped with a low air pressure warning signal.

If used and maintained properly, air brakes are a safe and effective way to stop large, heavy vehicles.

Some older vehicles have front brake limiting valves with "normal" and "slippery" settings. Setting a brake limiting valve to "slippery" reduces the vehicle's stopping power, so a driver should make sure the valve is in its "normal" position. Front wheel braking has proven to be effective in all driving conditions.

Never push down the brake pedal while the spring brakes are activated. The combined force of springs and air pressure could damage the brakes.

Anti-Lock Braking System (ABS) malfunction lamps are usually yellow. Even if the ABS isn't working properly, a driver will still have access to the vehicle's usual braking functions.

An air compressor governor will stop the compressor from pumping air once the air tanks are at an air pressure level around 125 psi. This air pressure level is referred to as the "cut-out" level.

When a brake pedal is pressed and the S-cam is turned, the S-cam presses the brake shoes against the inside of the brake drum. This causes friction and will cause the vehicle to slow.

Before starting down a hill, be sure to switch into a low gear. Gravity will increase your vehicle's speed as you travel downhill.

You must take an air brakes knowledge test to become licensed to operate a vehicle that is equipped with air brakes, including an air over hydraulic braking system.

Some air brake systems include an alcohol evaporator. The evaporator introduces alcohol into the braking system to prevent the formation of ice, which can cause damage.

It is essential that your low pressure warning light functions properly. After allowing the system to charge, you can test the warning signal by rapidly applying and releasing the brake pedal. This will release air from the braking system and the warning signal should come on when pressure drops to a dangerous level.

A vehicle with air brakes must be equipped with a low air pressure warning signal. If the warning signal goes off while a vehicle is being driven, the driver should bring the vehicle to a complete stop and have the system repaired.

Some air brake systems contain an alcohol evaporator. This evaporator introduces alcohol into the system to help prevent ice from forming in cold weather.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.

In a vehicle with dual parking control valves, there is a separate air tank that can be used to temporarily release the spring brakes if they have been activated due to low air pressure. Pushing in the proper control will release the spring brakes for a short period of time, allowing the driver to move the vehicle in an emergency.

Friction inside a brake drum is caused when the brake shoes and linings push against the inside of the drum. The friction in the drums will slow and stop the vehicle.

Air brakes are really three different braking systems: the service brake, the parking brake, and the emergency brake. Emergency and parking brakes are applied with mechanical force.

Compressed air in an air brake system usually has a certain amount of water and oil in it. This can harm the system if allowed to accumulate. Air tanks have drain valves to aid in removing water and oil from the compressed air.