The trailer hand valve (also referred to as the "trolley valve" or "Johnson bar") works the trailer brakes and should be used only when testing them. Using the trailer hand valve while driving could result in a skid.

To avoid a loss of control, you should accelerate slowly when driving in poor-traction conditions, such as rain or snow.

If your vehicle gets stuck on railroad tracks for any reason, you should immediately exit the vehicle and walk away from the tracks. Contact the proper emergency authorities.

Packaging can be an indicator of whether or not materials are hazardous. Cylinders and drums are often used to hold and transport hazardous materials.

Backing a truck is always dangerous because the driver may not be able to see everything behind them. CMV operators should avoid backing whenever possible.

When filling a tank that is divided by bulkheads, make sure that you do not place too much weight on the front or rear of the vehicle.

To prevent a vehicle with manual transmission from rolling backward when you begin to move forward from a stopped position, you can partly engage the clutch before removing your foot from the brake pedal.

An Anti-Lock Braking System (ABS) helps prevent wheel lockup during hard braking. If ABS detects impending lockup, it reduces braking pressure to a safe level.

When using a fire extinguisher, you should stand as far away from the fire as possible. Aim the extinguisher at the base of the fire, not at the flames. If you are not sure which kind of extinguisher should be used on a fire, particularly a hazardous materials fire, you should wait for the firefighters to arrive and allow them to extinguish it.

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

Making a sudden lane change can be dangerous while driving a combination vehicle. You can avoid the need to make a sudden lange change by looking down the road for upcoming obstacles that will require you to change lanes.

Regrooved, recapped, or retreaded tires are not permitted to be used on the front of a bus.

Missing clamps, spacers, studs, or lugs are dangerous, as are mismatched, bent, or cracked lock rings. Be sure your tires and rims are in good condition before operating your commercial motor vehicle.

When filling a tank that is divided by bulkheads, you must pay particular attention to weight distribution. Avoid putting too much weight on the front or rear of the tank.

It is important that all of a vehicle's equipment is in proper working condition before beginning a trip. If a trailer's spring brakes do not release when you push in the tractor air supply control, you should make sure the air line connections are properly attached and sealed.

Posted speed limits on exit and entrance ramps often show speeds that are safe to be driven by cars. However, these speed limits may be too fast for large or heavily-loaded vehicles and CMV drivers will likely need to slow down to a speed below the posted limit.

If your brakes fail while you are driving downhill, you should first look for an escape ramp to stop your vehicle. If no ramp is available, you should look for an alternative place to bring your vehicle to a stop, such as an open field or side road that flattens out or turns uphill.

Driving while fatigued can be extremely dangerous. Strategies for preventing drowsiness while driving include getting a full night's sleep before a trip; having someone ride with you; scheduling trips for times during which you are normally awake; and avoiding medications that may cause drowsiness. Exercising regularly can increase your energy levels and make you less likely to become tired while driving.

Among other information, shipping papers must include a description of the specific hazardous materials being transported.

When driving, you should regularly check your mirrors, both to be aware of traffic and to check for problems on your own vehicle.