The adjustment of your mirrors should be checked prior to the start of all trips. Adjust your mirrors as needed.

When driving, you should frequently check the mirrors on both sides of your vehicle.

In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.

There are two indicators that determine when you need to shift into a higher gear. One indicator is the engine speed (rpm). You should read your vehicle's manual to learn its rpm range and shift up when you reach the top of that range. The other indicator is road speed (mph). You should learn which speeds each gear can accommodate, then keep an eye on the speedometer and shift up as needed.

If your trailer begins to drift while you are backing, you should correct the drift immediately by turning the top of the steering wheel in the direction of the drift.

When inspecting the fifth wheel before a trip, you should ensure that the release arm is properly seated and the safety latch or lock is engaged. All components should be present and in proper working condition.

Eating heavy foods before driving or keeping the temperature in a cab too high can cause a driver to become drowsy while behind the wheel. Exercising and maintaining a healthy diet will help a driver to stay alert while driving.

At speeds below 40 mph, you should allow at least one second of following distance for every 10 feet of your vehicle. When traveling at higher speeds, follow the same formula, then add one additional second to your following distance.

An Anti-Lock Braking System (ABS) is in place as an addition to a braking system. It intervenes to prevent brakes from locking up during hard braking. If ABS is not working, the basic braking functions on a vehicle will still remain, so the driver can continue to drive and brake normally.

In heavy traffic, it is safest to travel at the same speed as other vehicles. If two vehicles continue to drive in the same direction at the same speed, they cannot hit each other.

Retarders are mechanisms in some vehicles that help slow a vehicle and reduce the need for braking. However, using a retarder may cause wheels to skid when they have poor traction. Turn off retarders when traveling under wet, snowy, or icy conditions.

Rollovers happen when an operator turns too fast. Drivers should be sure to slow down before entering turns and curves, especially when pulling a trailer.

Before a trip, you should ensure that air reaches all air brakes on all trailers by opening up the rear emergency line and service line shut-off valves and listening for escaping air. Close both shut-off valves before beginning to drive.

A visual low pressure warning signal should activate before air pressure drops to a level between 55 and 75 psi. This signal could be a light, a buzzer, or a wig wag.

Always begin signaling well in advance of a turn. This is the best way to ensure that other drivers do not try to pass you. Without using a turn signal, drivers may assume that you are merely slowing down or stopping when you are planning to turn.

The brakes in an air brake system use compressed air to function properly.

Backing a commercial motor vehicle is always dangerous because you cannot see everything behind you. When backing, make frequent checks of the mirrors on both sides of the vehicle.

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.

After starting a vehicle's engine, the warning lights and buzzers for oil, coolant, charging circuits, and the Anti-Lock Braking System (ABS) should go out right away.

It is best not to avoid driving in fog. However, if you must drive under foggy conditions, be sure to decrease your speed.