CDL School

Without ABS you still have normal brake functions. Drive and brake as you always have.

Inspect the tires more often than usual, or every two hours or every 100 miles when driving in very hot weather.

You must review the inspection report made by the previous driver. Only if defects reported earlier have been certified as repaired or not needed to be repaired, should you sign the previous driver's report.

When driving a loud bang, vibrations, or heavy steering can indicate that a tire has failed.

You need at least one second for each 10 feet of vehicle length at speeds below 40 mph. At greater speeds, you must add 1 second for safety. If your vehicle is 40 feet long and you are traveling at 50 mph, your following distance should be 5 seconds or more.

Explanation: Use high beams when it is safe and legal to do so. Use them when you are not within 500 feet of an approaching vehicle. 

You need at least 4/32-inch tread depth in every major groove on front tires. No fabric should show through the tread or sidewall. There should be no cuts or other damage.

Protect the accident area: if your vehicle is involved in the accident, try to get it to the side of the road, if you're stopping to help, park away from the accident, put on your flashers, and set out reflective triangles to warn other traffic.

The total stopping distance is the total minimum distance your vehicle has traveled, in ideal conditions; with everything considered, including perception distance, reaction distance and braking distance, until you can bring your vehicle to a complete stop. At 55 mph, your vehicle will travel a minimum of 450 feet.

Explanation: A safety relief valve is installed in the first tank the air compressor pumps air to. The safety valve protects the tank and the rest of the system from too much pressure. The valve is usually set to open automatically at 150 psi. 

In a front-wheel skid, the front end tends to go in a straight line regardless of how much you turn the steering wheel. On a very slippery surface, you may not be able to steer around a curve or turn.

ABS helps you avoid wheel lock up and maintain control. You will not be able to use stab braking on a vehicle equipped with ABS.

Do the following to correct a drive-wheel braking skid: stop braking letting the rear wheels roll again and keep the rear wheels from sliding; counter-steer as a vehicle turns back on course, it tends to keep on turning. Unless you turn the steering wheel quickly the other way, you may find yourself skidding in the opposite direction.

Because you cannot see everything behind your vehicle, backing is always dangerous. Avoid backing whenever you can. When you must back, here are a few simple safety rules: Start in the proper position, look at your path, use mirrors on both sides, back slowly, back and turn toward the driver's side whenever possible, and use a helper with clear hand signals whenever possible.

Most vehicles now have an ABS light on the instrument panel that will light up briefly when the vehicle is started to alert you that the vehicle has ABS, you can check to see if the vehicle was built on or after March 1, 1998, or you can check for wires from your brakes.

Your CDL will be disqualified after two or more convictions of any state law on texting while operating a CMV. No motor carrier shall allow or require its drivers to engage in texting while driving.

Slow down to a safe speed, and downshift to the right gear before entering the curve. This lets you use some power through the curve to help the vehicle be more stable while turning. It also allows you to speed up as soon as you are out of the curve.

Rear wheel braking skids occur when the rear drive wheels lock. Because locked wheels have less traction than rolling wheels, the rear wheels usually slide sideways in an attempt to "catch up" with the front wheels. With vehicles towing trailers, a drive-wheel skid can let the trailer push the towing vehicle sideways, causing a sudden jackknife.

Commercial vehicle must be equipped with 3 red reflective triangles, 6 fuses or 3 liquid burning flares.

Explanation: A skid happens whenever the tires lose their grip on the road. Most serious skids result from driving too fast for road conditions. Drivers who adjust their driving to conditions don't over-accelerate and don't have to over-brake or oversteer from too much speed. 

The governor controls when the air compressor will pump air into the air storage tanks. When air tank pressure rises to the "cut-out" level around 125 psi, the governor stops the compressor from pumping air. When the tank pressure falls to the "cut-in" pressure around 100 psi, the governor allows the compressor to start pumping again.

When you're in an accident and not seriously hurt, you need to act to prevent further damage or injury. The basic steps to be taken in any accident are to: protect the area, notify authorities, and care for the injured.

Remember that when the road is slippery, you need much more space to stop, and should keep more space in front of your vehicle.

Use windshield washer antifreeze to prevent freezing of the washer liquid.

If an oncoming driver has drifted into your lane, a move to your right is best. If that driver realizes what has happened, the natural response will be to return to their own lane. No one is likely to be driving on the shoulder, but someone may be passing you on the left.

Converter dollies built on or after March 1, 1998, are required to have antilock brakes. These dollies will have a yellow lamp on the left side of the dolly.

Explanation: If you stop on a two-lane road carrying traffic in both directions or on an undivided highway, place warning devices within 10 feet of the front or rear corners to mark the location of the vehicle and 100 feet behind and ahead of the vehicle, on the shoulder or in the lane you stopped in.

Whether or not you load and secure the cargo yourself, you are responsible for inspecting your cargo, recognizing overloads and poorly balanced weight, knowing your cargo is properly secured and does not obscure your view ahead or to the sides, knowing your cargo does not restrict your access to emergency equipment.

Poor weight balance can make vehicle handling unsafe. The cargo should be loaded so that it is balanced in the cargo area.

You should brake in a way that will keep your vehicle in a straight line and allow you to turn if it becomes necessary. You can use the "controlled braking" method or the "stab braking" method. 

Inspect the cargo and its securing devices again within the first 50 miles after beginning a trip. You need to inspect again after you have driven for 3 hours or 150 miles and after every break you take while driving.

A stale green light is a traffic light that is green when you first see it, thus you do not know how long it has been green - so we have to assume it will change at any moment.

Explanation: To drive a vehicle safely, you must be able to control its speed and direction. Safe operation of a commercial vehicle requires skill in accelerating, steering, stopping, and backing safely.

Snub braking method is used for steep downhill grades, in this method apply the brakes just hard enough to feel a definite slowdown. When your speed has been reduced to approximately five mph below your "safe" speed, release the brakes. When your speed has increased to your "safe" speed, repeat.

Heavy vehicles are often tailgated when they can't keep up with the speed of traffic. This often happens when you're going uphill. If a heavy load is slowing you down, stay in the right lane if you can. Going uphill, you should not pass another slow vehicle unless you can get around quickly and safely.

The gross combination weight (GCW” is the total weight of the GCWs of each unit of a combination vehicle – truck/tractor and trailer(s) added together.

While you are at the front of the vehicle, check the following items: headlight, low and high beam; windshield wiper arms for proper spring tension; wiper blades for damage; reflectors.

Cargo should have at least one tie-down for each ten feet of cargo. You will need two tie downs for a 20-foot load.

Do not try to downshift after your speed has already built up. You will not be able to shift into a lower gear. You may not even be able to get back into any gear and all engine braking effect will be lost.

The tire load is the maximum safe weight a tire can carry at a specified pressure. This rating is stated on the side of each tire.

It will take longer to stop, and it will be harder to turn without skidding, when the road is slippery. Wet roads can double stopping distance at any speed, reduce speed, and slow down gradually on a wet road. 

Never leave your vehicle unattended without applying the parking brakes or chocking the wheels. Your vehicle might roll away and cause injury and damage.

Perception Distance + Reaction Distance + Brake Lag Distance + Braking Distance = Total Stopping Distance

No matter how small the cargo, it should have at least two tie-downs.

When the low air pressure warning light and buzzer first come on, bring the vehicle to a safe stop right away, while you can still control the brakes.

In some weather, water or slush collects on the road. When this happens, your vehicle can hydroplane. The tires lose contact with the road and have little or no traction. You may not be able to steer or brake. Hydroplaning can occur at speeds as low as 30 mph. Hydroplaning is more likely if tire pressure is low, or the tread is worn.

If the load is more than two feet wide and extends more than four feet behind the rear of the vehicle, two square red flags must be placed at the end of the load.

Braking when a tire has failed could cause loss of control. Unless you're about to run into something, stay off the brakes until the vehicle has slowed down. Then brake very gently, pull off the road, and stop.