Arizona CDL DMV Endorsement Double 2

Wheels or rims that have had welding repairs are not safe for use. They should be replaced before the vehicle is taken on the road.

To reduce the risk of a surge in a tank vehicle, slow or stop while keeping a steady pressure on the brakes and do not release the brakes too early. Brake well in advance of a stop and increase your following distance.

When operating a double or triple, the shut-off valves at the rear of last trailer should be closed. All other shut-off valves should be open.

There should be at least 4/32 of an inch of tread depth in every major groove on front tires and 2/32 of an inch on other tires. Valve stems should not be cut or cracked. Tire sizes should not be mismatched.

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.

The trailer hand valve, also called the trolley valve or Johnson bar, is used to work the trailer brakes. It should be used only to test the brakes. Using it while a vehicle is in motion could cause a skid.

During a trip, you should regularly make checks to ensure that your vehicle is operating properly. Check the instrument panel and gauges; look at your mirrors; and examine the tires, cargo, and lights. Use all of your senses and be alert for anything that could be an early indication of trouble.

The first hazardous materials class includes explosives such as ammunition, dynamite, and fireworks.

Mirror adjustment should be checked prior to the start of any trip. If your vehicle has a trailer, the trailer must be straight in order for the mirrors to be checked accurately.

Empty trucks require longer stopping distances than full trucks because they have less traction available.

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.

Placards must be placed on the front, the rear, and both sides of a vehicle carrying hazardous cargo. They must be readable from any direction.

If you are attaching a second trailer to a combination, but you have doubts about the trailer's brakes, you should use wheel chocks to secure the trailer in place while coupling.

You should always complete an after-trip inspection of your vehicle at the end of a trip, day, or tour of duty. Complete a vehicle inspection report, if required.

Strategies to avoid becoming fatigued while driving include keeping the cab cool inside by using the air conditioner or opening a window; avoiding heavy foods; and taking rest breaks about every two hours or 100 miles.

If you are not certain that your vehicle will fit under overhead objects, you should slow down and take a different route, if possible.

If a trailer begins to jackknife, you should release the brakes and allow the trailer wheels to regain traction with the road. Do not apply the trailer hand brake to attempt to straighten out the rig because it will only prolong the skid. The application of brakes is what caused the wheels to lock in the first place.

B:C fire extinguishers are designed to work on electrical fires and burning liquids. Don't pour water on an electrical fire.

Slow down and be especially careful when driving in and around work zones, in places where the pavement drops off sharply at the edge of the road, when foreign objects are present on the road, and on freeway on- and off-ramps.

When stopping, apply gradual pressure to the brake pedal and stop smoothly. If stopping a manual transmission vehicle, push the clutch in when the engine is close to idle.