It is important to communicate your intentions to others on the road. Make sure to signal before turning or changing lanes, even if no other vehicles are nearby.

Always signal well ahead of a turn or lane change. Signal continuously until you have completed the turn or lane change, then be sure to cancel the signal so you do not confuse other drivers.

The trailer hand valve should not be used for parking. This could cause all of the air to leak out of the braking system, resulting in the brakes releasing. Instead, use the parking brake.

Combination vehicles require more space on the road than other vehicles. When entering or crossing traffic while driving a combination vehicle, it is especially important that there is a large enough gap in traffic for you to safely do so.

Truck tractors with air brakes built on or after March 1, 1997 must be equipped with Anti-Lock Braking Systems (ABS).

The service line, also called the control line or signal line, carries air to the trailer brakes and is controlled by the foot brake or trailer hand brake.

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

Failure to keep the fifth wheel plate properly lubricated can create friction between the tractor and trailer, causing steering problems.

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.

If your trailer starts to skid while you are braking, you should release the brakes and allow them to begin to regain traction. Once its wheels have regained their grip on the road, the trailer will begin to straighten out and follow the tractor.

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.

In vehicles equipped with an automatic tractor protection valve, the valve will pop out if air pressure drops to a level between 20 and 45 psi. When the valve pops out, the protection valve will close, stopping the flow of air.

When starting a trip, be sure that all shut-off valves are in the open position, except for the last valves on the rear trailer. It is important that air reaches the brakes on all trailers and that the air is not able to escape from the back of the vehicle.

While the manual contains all of the information needed to pass the written exam for a hazardous materials endorsement, it does not contain all of the information necessary to do the job safely. You can learn more by attending hazardous materials training courses.

You must have a CDL with a hazardous materials endorsement to operate a vehicle of any size to transport hazardous materials.

There are nine different hazard classes. A material's hazard class reflects its associated risks.

The right lanes of a roadway are generally intended for vehicles traveling more slowly than surrounding traffic. If being slowed down by a heavy load, you should stay in the right lane.

Wheels or rims with welding repairs are not safe.

At dawn or dusk, and in snowy or rainy conditions, you should turn on your headlights to make it easier for other road users to see your vehicle.

A driver transporting chlorine in cargo tanks must keep an approved gas mask and an emergency kit in their vehicle.