Tennessee CDL DMV Endorsement Double 2

If someone is tailgating you, it is a good idea to open up the space ahead of your vehicle to make it easier for the driver to pass you. Increasing your speed is not a good idea because the driver may continue to tailgate you at the higher speed, only increasing the danger.

In newer vehicles with air brakes, the parking brakes are controlled by a diamond-shaped yellow knob. Pull the knob out to activate the parking brakes and push it in to release them.

An empty combination vehicle will come to a complete stop more slowly than a fully-loaded vehicle. The stiff suspension springs and strong brakes will have lower traction on a light trailer than they would if the vehicle carried more weight.

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.

If you begin to feel sleepy while driving, the only safe response is to stop driving and get some sleep. Attempting to fight off exhaustion is dangerous and a major cause of fatal crashes. Stimulants are not a safe solution because they may help keep you awake but will not make you more alert. Once stimulants wear off, you will be even more tired than you were originally.

When inspecting a vehicle's suspension, you should look for broken or missing leaves in the leaf springs. Any defect of this kind is dangerous. If one-fourth or more of the leaves are missing from any leaf spring, the vehicle must be put out-of-service.

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.

Traction is friction between your tires and the surface of the road. Adequate traction is necessary for braking and steering.

To test the trailer service brakes, you should first ensure that the braking system has a normal air pressure level, then release the parking brake. You should then move the vehicle forward slowly and apply the brakes with the hand control. If the trailer service brakes are working properly, you will feel the brakes activate.

Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.

An air compressor governor will stop the compressor from pumping air once the air tanks are at an air pressure level around 125 psi. This air pressure level is referred to as the "cut-out" level.

If a pre-trip inspection reveals anything unsafe about your vehicle, you must get it repaired. It is illegal to operate an unsafe vehicle.

When accelerating, speed up smoothly and gradually so your vehicle does not jerk. Rough acceleration can cause mechanical damage.

An Anti-Lock Braking System (ABS) is in place as an addition to a braking system. It intervenes to prevent brakes from locking up during hard braking. When driving a vehicle with ABS, you should brake in the same way that you would in a vehicle without ABS. It will not necessarily shorten your stopping distance.

During a pre-trip inspection, you should check for emergency equipment, including spare electrical fuses; three red reflective triangles, six fuses, or three liquid burning flares; and at least one properly charged and rated fire extinguisher.

Without a working Anti-Lock Braking System (ABS), your vehicle will still have normal brake function. Continue to drive and brake as you normally would and have your ABS serviced as soon as possible.

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.

The liver removes alcohol from the body at a fixed rate. Despite popular belief, tricks like drinking coffee or taking a cold shower will not speed up the process. The only way to become sober is to allow your body the time it needs to remove the alcohol from your system.

Wheels and rims with welding repairs are not safe to be used. Replace any damaged wheels and rims.