Choose A Section:Go!
When going down a mountain, what is the principal way of controlling your speed?
Which of the following statements are not true about the way ABS works?
Define "Braking Distance":
Braking Distance. The distance your vehicle will travel, in ideal conditions, while you are braking. At 55 mph on dry pavement with good brakes, it can take about 216 feet.
Of all the space around your vehicle, which is the most important?
Which of the following are true about ABS?
Some drivers try to help others by signaling when it is safe to pass. Should you do this, and why?
Should you use engine brakes on slick roads, and why?
Adjust Turning and Braking to Conditions. Make turns as gently as possible. Do not brake any harder than necessary and do not use the engine brake or speed retarder. They can cause the driving wheels to skid on slippery surfaces.
Most serious skids result from:
When you drive a vehicle with ABS, you should brake as you always have. There is only one exception to this procedure:
What type of railroad crossing does not have any type of traffic control device and leaves the decision to stop or proceed entirely in your hands.
Passive Crossings. This type of crossing does not have any type of traffic control device. The decision to stop or proceed rests entirely in your hands. Passive crossings require you to recognize the crossing, search for any train using the tracks and decide if there is sufficient clear space to cross safely. Passive crossings have yellow circular advance warning signs, pavement markings, and crossbucks to assist you in recognizing a crossing.
Active Crossings. This type of crossing has a traffic control device installed at the crossing to regulate traffic at the crossing. These active devices include flashing red lights with or without bells and flashing red lights with bells and gates.
Choose your next section:
The Safe Driving portion of the CDL manual will be on the General Knowledge portion of the CDL permit written exam. This is a rather large section of the CDL Manual and also includes basic information on hazardous materials (HazMat) that all drivers should know. Here are the basics of what you must know:
Safety is the most important reason for completing a vehicle inspection. A vehicle defect found during an inspection could prevent problems later, such as a breakdown on the road that will cost time and dollars, or even worse, a crash caused by the defect.
Federal and state laws require that drivers inspect their vehicles. Federal and state inspectors also may inspect your vehicles. If they judge the vehicle to be unsafe, they will put the vehicle "out of service" until it is repaired.
Generally speaking the major things you'll be checking will be:
In order to obtain a CDL, you will be required to pass a pre-trip vehicle inspection test. You will be tested to see if you know whether your vehicle is safe to drive. You will be asked to do a pre-trip inspection of your vehicle and explain to the examiner what you would inspect and why.
The pre-trip inspection is a long, exhaustive inspection and we're not going to cover it all here. But we do have an excellent pre-trip inspection in our forum, done by one of our moderators who is currently a trainer at Prime Inc.
Here are some questions you should be able to answer before taking your CDL permit exam:
To drive a vehicle safely, you must be able to control its speed and direction. Safe operation of a commercial vehicle requires skill in:
When you have to backup, here are some simple safety rules:
There are a couple of special conditions where you should downshift:
Before Starting Down a Hill - Slow down and shift down to a speed that you can control without using the brakes hard. Otherwise the brakes can overheat and lose their braking power. Downshift before starting down the hill. Make sure you are in a low enough gear, usually lower than the gear required to climb the same hill.
Before Entering a Curve - 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.
This is very important to know and may be asked about on your CDL exams:
Total Stopping Distance = Perception Distance + Reaction Distance + Braking Distance
Perception distance - The distance your vehicle travels, in ideal conditions, from the time your eyes see a hazard until your brain recognizes it. Keep in mind, certain mental and physical conditions can affect your perception distance. It can be affected greatly depending on visibility and the hazard itself. The average perception time for an alert driver is 1 3/4 seconds. At 55 mph, this accounts for 142 feet traveled.
Reaction distance - The distance you will continue to travel, in ideal conditions; before you physically hit the brakes in response to a hazard seen ahead. The average driver has a reaction time of 3/4 second to one second. At 55 mph this accounts for 61 feet traveled.
Braking distance - The distance your vehicle will travel, in ideal conditions; while you are braking. At 55 mph on dry pavement with good brakes, it can take about 216 feet.
Total stopping distance - 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 419 feet. (See Figure 2.11.)
The Effect of Speed on Stopping Distance - The faster you drive, the greater the impact or striking power of your vehicle. When you double your speed from 20 to 40 mph the impact is four times greater. The braking distance is also four times longer. Triple the speed from 20 to 60 mph and the impact and braking distance is nine times greater. At 60 mph, your stopping distance is greater than the length of a football field. Increase the speed to 80 mph, and the impact and braking distance are 16 times greater than at 20 mph. High speeds greatly increase the severity of crashes and stopping distances. By slowing down, you can reduce braking distance.
The Effect of Vehicle Weight on Stopping Distance - The heavier the vehicle, the more work the brakes must do to stop it and the more heat they absorb. The brakes, tires, springs and shock absorbers on heavy vehicles are designed to work best when the vehicle is fully loaded. Empty trucks require greater stopping distances because an empty vehicle has less traction.
Sometimes it is hard to know if the road is slippery. Following are signs of slippery roads:
Following are some rules to help prevent right-turn crashes:
Whenever you are driving a vehicle and your attention is not on the road, you are putting yourself, your passengers, other vehicles and pedestrians in danger. Distracted driving can result when performing any activity that may shift your full attention from the driving task. Taking your eyes off the road or hands off the steering wheel presents obvious driving risks. Mental activities that take your mind away from driving are just as dangerous. Your eyes can gaze at objects in the driving scene but fail to see them because your attention is distracted elsewhere.
Activities that can distract your attention include: talking to passengers; adjusting the radio, CD player or climate controls; eating, drinking or smoking; reading maps or other literature; picking up something that fell; reading billboards and other road advertisements; watching other people and vehicles including aggressive drivers; talking on a cellphone or CB radio; using telematic devices (such as navigation systems, pagers, etc.); daydreaming or being occupied with other mental distractions.
Railroad crossings with steep approaches can cause your unit to hang up on the tracks. Never permit traffic conditions to trap you in a position where you have to stop on the tracks. Be sure you can get all the way across the tracks before you start across. It takes a typical tractor-trailer unit at least 14 seconds to clear a single track and more than 15 seconds to clear a double track.
Do not shift gears while crossing railroad tracks.
Select the Right Gear Before Starting Down the Grade.
You must use the braking effect of the engine as the principal way of controlling your speed. The braking effect of the engine is greatest when it is near the governed rpms and the transmission is in the lower gears. Save your brakes so you will be able to slow or stop as required by road and traffic conditions.
Shift the transmission to a low gear before starting down the grade. 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. Forcing an automatic transmission into a lower gear at high speed could damage the transmission and also lead to loss of all engine braking effect.
With older trucks, a rule for choosing gears is to use the same gear going down a hill that you would need to climb the hill. However, new trucks have low friction parts and streamlined shapes for fuel economy. They may also have more powerful engines. This means they can go up hills in higher gears and have less friction and air drag to hold them back going down hills. For that reason, drivers of modern trucks may have to use lower gears going down a hill than would be required to go up the hill. You should know what is right for your vehicle.
Remember — The use of brakes on a long and/or steep downgrade is only a supplement to the braking effect of the engine. Once the vehicle is in the proper low gear, the following are the proper braking techniques:
For example, if your "safe" speed is 40 mph, you would not apply the brakes until your speed reaches 40 mph. You now apply the brakes hard enough to gradually reduce your speed to 35 mph and then release the brakes. Repeat this as often as necessary until you have reached the end of the downgrade.
If somebody suddenly pulls out in front of you, your natural response is to hit the brakes. This is a good response if there is enough distance to stop and you use the brakes correctly. 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.
Controlled braking: With this method, you apply the brakes as hard as you can without locking the wheels. Keep steering wheel movements very small while doing this. If you need to make a larger steering adjustment or if the wheels lock, release the brakes. Re-apply the brakes as soon as you can.
Do not jam on the brakes: Emergency braking does not mean pushing down on the brake pedal as hard as you can. That will only keep the wheels locked up and cause a skid. If the wheels are skidding, you cannot control the vehicle.
When you are sleepy, trying to "push on" is far more dangerous than most drivers think. It is a major cause of fatal accidents. Here are some important rules to follow: