CDL School

If the surface is icy, reduce speed to a crawl and stop driving as soon as you can safely do so.

Blocking is used in the front, back, and/or sides of a piece of cargo to keep it from sliding. Blocking is shaped to fit snugly against cargo. It is secured to the cargo deck to prevent cargo movement.

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.

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

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

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. 

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

The B:C type fire extinguisher is designed to work on electrical fires and burning liquids. These are usually the following types of fire extinguishers: Regular Dry Chemical, KCl Dry Chemical, Carbon Dioxide (Dry), Halogenated Agent (Gas).

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.

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 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.

To test the parking brake: fasten safety belt, set parking brake, place vehicle into a low gear, and gently pull forward against parking brake to make sure the parking brake holds.

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.

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.

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.

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. 

Strong winds make it difficult to stay in your lane. The problem is usually worse for lighter vehicles. This problem can be especially bad coming out of tunnels.

Front-end header boards ("headache racks") protect you from your cargo in case of a crash or emergency stop. The front-end structure should block the forward movement of any cargo you carry.

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

Most good drivers look at least 12 to 15 seconds ahead. That means looking ahead at the distance you will travel in 12 to 15 seconds. At lower speeds, that's about one block. At highway speeds it's about a quarter of a mile.

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.

Tire problems include: too much or too little air pressure, bad wear, at least 4/32-inch tread depth on front tires, 2/32 inch on all other tires, no fabric should show through the tread or sidewall, cuts or other damage, tread separation, dual tires that come in contact with each other or parts of the vehicle, mismatched sizes, radial and bias-ply tires used together.

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.

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.

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.

You will lose your CDL for at least one year for a first offense for: Driving a CMV if your blood alcohol concentration is .04% or higher or driving a CMV under the influence of alcohol.

Stopping is not always the safest thing to do in an emergency. When you don't have enough room to stop, you may have to steer away from what's ahead. Remember, you can almost always turn to miss an obstacle more quickly than you can stop.

Don't over steer, over accelerate, or over brake by adjusting to conditions while driving. These include traction, curves, visibility, traffic and hills.

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.

Driving too fast is a major cause of fatal crashes. You must adjust your speed depending on driving conditions. These include traction, curves, visibility, traffic, and hills.

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. 

If for any reason you get stuck on the tracks, get out of the vehicle and away from the tracks. Check signposts or signal housing at the crossing for emergency notification information. Call 911 and give the location of the crossing using all identifiable landmarks, especially the DOT number, if posted.

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.

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.

Some vehicles have sight glasses, see-through coolant overflow containers, or coolant recovery containers. These permit you to check the coolant level while the engine is hot. If the container is not part of the pressurized system, the cap can be safely removed, and coolant added even when the engine is at operating temperature.

Wedge brakes and disc brakes are less common than s-cam brakes.

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

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.

All vehicles with air brakes have a pressure gauge connected to the air tank. If the vehicle has a dual air brake system, there will be a gauge for each half of the system.

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.

Watch for: vehicles that may drift over the lane divider lines or within their own lane; vehicles traveling at inconsistent speeds; drivers who are preoccupied with maps, food, cigarettes, cell phones, or other objects; drivers who appear to be involved in conversations with their passengers.

To know how much space you have, wait until the vehicle ahead passes a shadow on the road, a pavement marking, or some other clear landmark. Then count off the seconds like this: "one thousand-and-one, one thousand-and-two" and so on, until you reach the same spot.

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.

Too much weight on the steering axle can cause hard steering. It can damage the steering axle and tires.

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.

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. 

When people are working on the road, it is a hazard. There may be narrower lanes, sharp turns, or uneven surfaces.

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.