On a compressed gas tank, liquid discharge valves must always be kept closed, except during loading and unloading.

If you begin to feel drowsy while driving, the best thing to do is to stop and get some sleep. A driver trying to push on and finish a trip while fatigued is a major cause of fatal accidents.

A broken exhaust system can let poisonous fumes into a vehicle's cab or sleeper berth. Be sure to inspect your exhaust system for any loose, broken, or missing parts.

Be careful around pedestrians, joggers, and cyclists who are wearing headphones. They may be unable to hear your vehicle approaching and may do dangerous things because they do not know you are there.

Never use the trailer hand valve while parking because doing so may release the air pressure from the braking system, releasing the brakes that are holding the vehicle in place. Instead, use the parking brake or wheel chocks.

When carrying Division 1.1, 1.2, or 1.3 explosives, do not park within 300 feet of a bridge, tunnel, or building; a place where people gather; or an open fire.

If a cargo of hazardous materials begins to leak, do not move your vehicle any more than safety requires. If you continue to drive, an even larger area will become contaminated. Instead, you should park your vehicle, secure it, stay with the vehicle, and contact the proper emergency personnel. If you do not have access to a phone, you should send someone else to get help.

In heavy traffic, it is safest to match the speed of surrounding vehicles. Vehicles traveling in the same direction at the same speed are unlikely to collide. However, you should not exceed legal speed limits.

When driving in reverse, it is always recommended that a driver backs their vehicle toward its left side. This will allow the driver the best possible view of the rear of their vehicle.

Fatigued drivers are slower to see or react to hazards than drivers who are not fatigued. Drivers are impaired in their ability to make critical decisions when they are driving drowsy.

A person attending a parked placarded vehicle must be either awake inside the vehicle or they must be within 100 feet of it. If not inside the vehicle itself, the person must have a clear view of the vehicle. The person attending may not be inside the sleeper berth.

When backing with a trailer, begin by turning the steering wheel in the direction opposite of the turn. Once the trailer starts to turn, reverse the direction of the steering wheel to follow the trailer.

It is important to observe other drivers' actions and identify clues that a person could be driving impaired. Drivers who have had too much to drink, are sleepy, are on drugs, or are ill can present hazards to other drivers. One sign that a driver may be impaired is that they have their windows rolled down in cold weather.

While driving, you should watch your vehicle's gauges for signs of trouble. Be sure to inspect your gauges before beginning a trip to ensure that they are in proper working order.

Push in the trailer air supply control to supply the trailer with air. Pull out the trailer air supply control to turn off the air supply and activate the emergency brakes.

If you are experiencing a truck fire, you should not attempt to open trailer doors without first feeling the doors to see if they are hot. If the doors are hot, there may be a cargo fire. Leave the doors closed if there is a cargo fire.

When driving at dawn, at dusk, or in inclement weather, you should use your headlights on their low beam setting to increase your visibility.

When backing a truck, always use the mirrors on both sides of the vehicle. Have someone help you whenever possible.

Texting while driving is particularly dangerous because it is both a mental and physical distraction to the driver. In addition to diverting a driver's mental attention away from the road, texting requires a person to remove at least one hand from the vehicle's controls.

When examining the engine compartment during a pre-trip inspection, you should check the engine oil level, the radiator coolant level, and the condition of the hoses.