CDL School

You should check your mirrors every 8 to 10 seconds to know what is going on around your vehicle.

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. 

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.

Short breaks can keep your alert. But the time to take them is before you feel really drowsy or tired. Stop often. Walk around and inspect your vehicle. It may help to do some physical exercise.

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: ¾ second to 1 second. At 55 mph this accounts for 61 feet traveled.

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.

Air brakes are three different systems: service brake, parking brake, and emergency brake.

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.

Air pressure increases with temperature. Do not let air out or the pressure will be too low when the tires cool off.

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. 

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.

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.

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

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

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.

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.

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.

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.

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.

Accident statistics show that the chance of a crash is much greater for drivers who have been drinking than for drivers who have not.

The Gross Vehicle Weight Rating (GVWR) is the value specified by the manufacturer as the loaded weight of a single vehicle.

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

Basic method for shifting up: release accelerator, push in clutch and shift to neutral at the same time. Release clutch. Let the engine and gears slow down to the rpm required for the next gear. Push in clutch and shift to the higher gear at the same time. Release clutch and press accelerator at the same time.

Empty trucks actually require greater stopping distances because an empty vehicle has less traction. It can bounce and lock up its wheels, giving much poorer braking.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

Shut off the engine and take the key with you so someone else won't move the truck while you are under it.

Use either the tachometer or the speedometer and upshift/downshift at the right rpm or road speed.

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. 

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

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.

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.

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

Before you begin backing, work out a set of hand signals that you both understand. Agree on a signal for "stop."

If you find yourself being tailgated: avoid quick changes, signal early, reduce speed very gradually, increase your following distance, and don't speed up.

What you should do is make a lane change or slow down to prevent a crash if the car suddenly cuts in front of you, and you should not honk or stay close behind the car.

With the stab braking method, you apply your brakes all the way and release brakes when wheels lock up. 

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.