CDL School

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.

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.

A hazard is any road condition or other road user (driver, bicyclist, pedestrian) that is a possible danger.

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

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.

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

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.

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

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

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

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 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).

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.

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.

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.

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.

Explanation: Don't roll back when you start. You may hit someone behind you. If you have a manual transmission vehicle, partly engage the clutch before you take your right foot off the brake. Put on the parking brake whenever necessary to keep it from rolling back. Release the parking brake only when you have applied enough engine power to keep from rolling back 

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. 

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.

Preventing drowsiness before a trip: Get adequate sleep (8 to 9 hours), prepare route, schedule trips for the hours you are normally awake, drive with a passenger, avoid medications that cause drowsiness.

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.

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

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

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.

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

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.

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.

Explanation: Warn following drivers by flashing your brake lights, don't stop suddenly. If you see a hazard that will require slowing down, warn the drivers behind by flashing your brake lights. At dawn, dusk, in rain, or snow, you need to make yourself easier to see so turn on your lights. 

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

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

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.

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.

In a front-wheel skid, the front end tends to go in a straight line regardless of how much you turn the steering wheel.

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.

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

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.

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.

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

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.

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

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. 

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

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.

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.

Explanation - For an e-route inspection: check the tires, wheels, and truck body for signs of heat whenever you stop during a trip.

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.

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

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