Increasing your vehicle's speed will increase your vehicle's striking power and braking distance. Doubling your vehicle's speed from 20 to 40 mph will multiply its braking distance by four.

Rollovers happen when a vehicle is driven too fast. To reduce the risk of rollover, make sure the weight of cargo is loaded low to the ground, and that you take turns and curves slowly.

Hazardous materials must be diamond-shaped and a size of at least 10 ¾ square inches.

In an air brake system, the air storage tanks must be drained to remove accumulated water and compressor oil. Failing to do so can cause damage. Manually operated drains should be used at the end of each day of driving.

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.

If you are unsure if a trailer is equipped with an Anti-Lock Braking System (ABS), look under the vehicle for the electronic control unit and wheel speed sensor wires coming from the back of the brakes.

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.

Never unlock the pintle hook with the dolly still under the rear trailer. This could cause the dolly tow bar to fly up, possibly causing serious injury.

While driving, you should continually scan the road to spot potential hazards in advance. Make emergency plans for how to deal with the hazards if they become dangerous.

If you must drive in reverse, you should back up slowly and use the mirrors on both sides of your vehicle. Use a helper to monitor your blind spots whenever possible. You and the helper should agree on a signal for "stop."

When inspecting an exhaust system, you should verify that parts of the system are not loose, broken, or missing. The system's parts must be properly mounted and should not be rubbing against moving parts of the vehicle.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A triple combination should have a leakage rate no higher than 6 psi in a minute during an applied leakage test.

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.

Potential problems to check for when inspecting brakes include cracked drums; shoes or pads with oil, grease, or brake fluid on them; and shoes that are missing, broken, or worn dangerously thin.

The parking brake in a vehicle with air brakes should be used every time the vehicle is parked.

Because the weight of cargo gives them a higher center of gravity, fully-loaded rigs are 10 times more likely to roll over in a crash than empty rigs.

If you must stop on the shoulder of a road, put out your emergency warning devices within 10 minutes of stopping. When pulling off the road to stop, be sure to turn on your four-way emergency flashers.

To travel safely, it is essential that you know what is happening on all sides of your vehicle at all times. Check all mirrors frequently while driving.

If you are involved in a crash, the three basic things you need to do are protect the area, notify the proper authorities, and care for anyone injured. It is important to protect the accident site immediately after the accident occurs to help prevent another crash from happening in the same location.

Double and triple combinations are the most vulnerable to turning over as a result of the "crack-the-whip" effect.