CDL School

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

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.

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.

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.

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.

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.

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.

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. 

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.

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.

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.

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.

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.

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

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.

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.

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.

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

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.

 If possible, avoid using the brakes until your speed has dropped to about 20 mph, and gently return to the road.

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.

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

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.

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 

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

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.

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.

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

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

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.

Hauling liquids in tanks requires special skills because of the high center of gravity and liquid movement.

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.

Before you change lanes, you must first make sure that no vehicles are hiding in your blind spots.

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

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.

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

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.

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

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

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.

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.

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

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

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.

Low air warning devices (buzzer, light, flag) should activate before air pressure drops below 60 psi or level specified by the manufacturer.

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.

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.