Texas CDL DMV Endorsement Double 1

When turning quickly to avoid an object, turn only as much as is necessary to clear it. Do not apply the brakes while turning.

Fatigue and lack of alertness are major hazards when driving at night. Most people are the least alert at night, especially after midnight.

Before starting down a hill, be sure to switch into a low gear. Gravity will increase your vehicle's speed as you travel downhill.

If you use the parking brakes when the weather is very wet and the temperature is below freezing, the brakes may become frozen, preventing the vehicle from moving.

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.

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.

When a vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking. This effect is especially pronounced on vehicles with trailers.

Mirrors should be checked prior to the beginning of a trip. On a vehicle with a trailer, mirror adjustment can only be checked accurately if the connected trailer is straight.

On newer vehicles, the trailer air supply control is an eight-sided red knob. It's used to control the tractor protection valve.

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.

Before driving during the winter, make sure to check your defrosting and heating equipment, coolant and antifreeze levels, wipers and washers, tire tread, tire chains, lights, reflectors, and exhaust system. Clear ice and snow from all windows, mirrors, hand holds, steps, deck plates, and radiator shutters. Make sure the winterfront is not closed too tightly.

Bridges usually freeze before the rest of the road. You should be especially careful when crossing bridges if the temperature is near the freezing point.

At times when visibility is low, you should turn your headlights on to the low beam setting. If you are having a difficult time seeing others, they are probably having a difficult time seeing you.

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.

It is essential that drivers of doubles and triples are able to correctly couple and uncouple their trailers. Improperly coupling and uncoupling trailers is extremely dangerous.

When performing a static leakage test on a single vehicle with air brakes, the leakage rate should be no more than 2 psi in a minute. If air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

Air brake system tanks must contain drain valves. These valves are used to drain accumulated oil and water from the tanks and may be either manually or automatically operated.

The trailers in double and triple combinations should be checked in walk-around inspections.

It is important that all of your vehicle's equipment is in proper working condition before you begin 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.

If you need to make an emergency stop, you can use either the controlled braking method or the stab braking method. It's important to brake in a way that keeps your vehicle traveling in a straight line while still allowing you to turn, if necessary.