In an air brake system, pressing and releasing the brake pedal unnecessarily can release air from the braking system faster than the compressor can replace it.

The air compressor of an air brake system is connected to the engine through gears or a v-belt. The compressor may be air-cooled or cooled by the engine cooling system.

The total stopping distance for vehicles equipped with air brakes is made up of four factors: perception distance, reaction distance, brake lag distance, and braking distance. When braking at a speed of 55 mph while driving on dry pavement, the brake lag can add around 32 feet to the vehicle's total stopping distance.

When inspecting the convertor dolly, ensure that all components are present and in proper working condition. The air lines should be securely attached to the proper glad hands and should not contain any leaks. They should be attached with enough slack to allow for easy turning.

Mirrors should be checked prior to the beginning of a trip. On a vehicle with a trailer, mirror adjustment can only be checked accurately if the connected trailer is straight.

The majority of heavy-duty vehicles are equipped with dual air brake systems.

In an air brake system, a low pressure warning signal should activate if the pressure in the air tanks falls to a level below 60 psi. This signal may be in the form of a warning light or a wig wag.

It is important to always perform a thorough pre-trip inspection before beginning a drive. When inspecting the upper fifth wheel, the glide plate should be securely mounted to the trailer frame.

If you are being followed too closely, you should increase your following distance, avoid making quick moves, and avoid relying on tricks (such as flashing your lights) to help other drivers pass. Speeding up may only increase the danger by causing the tailgater to continue tailgating you at a higher speed.

Backing is always dangerous and should be avoided whenever possible. When parking, you should seek a space that allows you to pull forward when exiting. Try not to park near smaller vehicles to help you avoid maneuvering issues.

Tractors without semi-trailers are referred to as bobtail tractors. Operating a bobtail tractor requires drivers to exercise caution.

If a tractor-trailer is so equipped, the trailer brake hand valve can be used to stop the vehicle from rolling back when being started from a stop.

The doors of a trailer should be not be opened in the event of a cargo fire, especially if the cargo includes hazardous materials. Opening trailer doors would increase the fire's oxygen supply, potentially causing the fire to increase in size.

For safety, most heavy-duty vehicles are equipped with dual air brake systems.

On a downgrade, the force of gravity will cause a vehicle's speed to increase. When approaching a downgrade, choose to travel at a speed that will be safe for the size and weight of your vehicle.

All commercial motor vehicles are required to be equipped with the proper emergency equipment. This may include spare electrical fuses; three red reflective triangles, six fuses, or three liquid burning flares; and at least one properly charged and rated fire extinguisher.

When performing a static leakage test on a single vehicle with air brakes, the leakage rate should be no more than 2 psi in a minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

When inspecting a vehicle equipped with power steering, check the hoses, pumps, and fluid level. Be sure to check for and repair leaks before operating the vehicle.

A large vehicle may need to swing right to make a left turn. If an intersection has two left turn lanes, the driver should choose the righthand land to begin their turn.

In places where water collects on the road, it is possible for a vehicle to hydroplane. Low tire pressure or worn tire tread makes this more likely to happen. If there is enough water on a road surface, hydroplaning can occur at speeds as low as 30 mph.