When braking a vehicle equipped with antilock brakes the. Hydraulically braked trucks and buses with a gross vehicle weight rating of 10,000 lbs or more built on or after march 1. Also referred to as antiskid braking system sometimes, it enables the wheels of a vehicle to maintain tractive contact with the ground so that they. As the name signifies, the antilock braking system is a safety system in cars and other automobiles that keeps their wheels from locking up and helps their drivers to maintain steering control. Trust the commercial vehicle abs pioneer and its marketleading antilock braking systems. Anti lock braking systems abs are compatible with air brakes and help a driver maintain control of their vehicle by preventing wheel lockup. Helps prevent wheels from locking up possibly allowing the driver to steer to safety. Antilock braking systems abs are compatible with air brakes and help a driver maintain control of their vehicle by preventing wheel lockup. Antilock braking system or the commonly known abbreviation abs were introduced as standard on many cars during the mid1980s. How to use antilock braking systems newly licensed drivers. The anti lock braking system needs some way of knowing when a wheel is about to lock up. Drivers who learned to drive before abs became standard likely. If the abs isnt working, the vehicles basic braking functions are not affected. The service brake, emergency brake, and the inverse system.
An abs doesnt necessarily decrease braking distance. At all other times the brake system will operate normally. An antilock braking system abs intervenes to reduce brake pressure if there is a risk of wheel lockup. Abs operates by preventing the wheels from locking up during braking, thereby maintaining tractive contact with the road surface.
Only used if the vehicle does not have antilock brakes 14. Anti lock brakes cannot compensate for driving faster, more aggressively, or maintaining unsafe following distances. It keeps the wheels rotating, which gives the driver steering control. Using air brakes and stopping distance high road online cdl. Hazardous materials rules for all commercial drivers. When driving a vehicle equipped with an antilock braking system abs, you should. Many of the commercial vehicles on the road today use air brakes for their braking system. Drive safely, because your antilock brakes are only as good as the driver using them. Dec 29, 2015 abs stands for anti lock braking system abs, and helps the tires on your vehicle to maintain contact with the road while you are braking. Common on some commercial vehicles, an air brake uses compressed air to stop heavy vehicles. Pressing the brakes hard enough to lock up the wheels, then releasing and then reapplying again c. Jan 20, 2017 an anti lock braking system or anti skid braking system abs is an automobile safety system that allows the wheels on a motor vehicle to maintain tractive contact with the road surface according to driver inputs while braking, preventing the wheels from locking up and avoiding uncontrolled skidding.
They cannot guarantee recovery from a spin or skid prior to an emergency braking situation. Home car information useful driving terms antilock braking system antilock braking system abs absantilock braking system is a modern technology found on newer cars that allows the vehicle to be steered safely while braking hard. You may or may not be able to stop faster with abs, but you should be able to steer around an obstacle while braking, and avoid skids caused by over braking. Abs antilock braking system antilock braking systems use wheel speed sensors and ecus electronic control units to prevent the wheels on a truck locking up. Antilock breaking system abs an antilock braking system abs is used on many commercial vehicles to control the braking force when hauling large loads. Abs anti lock braking system is an automobile safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up that is, ceasing rotation and therefore avoiding skidding. Dec, 2016 anti lock braking systems have been a standard feature on vehicles for more than a quarter century. The abs quiz will test your knowledge just as the real theory test will.
Tips for driving with abs antilock brake systems fourwheel abs is a safe, effective braking system when used properly. These braking systems are especially helpful during adverse weather conditions, when heavy braking on wet or slick surfaces could cause wheel lockup. An anti lock braking system abs is a safety anti skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses. Applying the brakes hard enough for the wheels to lock up b. The correct answer depends on whether the car youre driving has an antilock braking system, or abs. It intervenes to prevent brakes from locking up during hard braking. Developed in 1929 for use on aircraft, motorists first experienced the benefits of abs in the jensen ferguson formula, a fourwheeldrive car unveiled in 1966.
If you are a little unsure on exactly what antilock brakes are, how they work and how best to use them, take a read of the antilock braking system guide before taking the antilock brakes theory test quiz below. If you are a little unsure on exactly what anti lock brakes are, how they work and how best to use them, take a read of the anti lock braking system guide before taking the anti lock brakes theory test quiz below. Use your trusty multimeter to check continuity through wheel speed sensors. A when you turn on the ignition, a yellow abs malfunction lamp lights up on the instrument panel. The control of an antilock braking system abs is a difficult problem due to its strongly.
If your anti lock braking system light comes on briefly when you start the car, the wheel will wobble and you will feel a slight pull in the direction of the blowout if a rear tire blows out. Antilock braking systems alaska commercial drivers. If your antilock braking system light comes on briefly when you start the car, the wheel will wobble and you will feel a slight pull in the direction of the blowout if a rear tire blows out. Abs only activates when wheels are about to lock up. There was the old 121 system that the drivers hate. Abs is a computerized system that keeps your wheels from locking up during hard brake applications. A combination vehicle where towing a vehicle with a gvwr of more than 10,000 pounds or a combination gvwr of more than 26,000 pounds. Antilock braking systems abs help you steer in emergencies by restoring traction to your tires. If an emergency arises, the driver should use the controlled or stab braking method.
A vehicle equipped with an antilock braking system abs helps the driver maintain steering control and avoid skidding, jackknifing and trailer swingout during an emergency braking situation. You will be tested to see if you know whether your vehicle is safe to drive. Anti lock breaking system abs an anti lock braking system abs is used on many commercial vehicles to control the braking force when hauling large loads. If the antilock braking system abs is malfunctioning. If the antilock brake system fails or malfunctions, the driver must resort to stopping the vehicle by using the normal airbrake method. When your other wheels lock up, you may skid or even spin the vehicle. Antilock braking systems alaska commercial drivers manual. The driver would need to step on the brake pedal when braking a vehicle equipped with anti lock brakes. Abs operates by preventing the wheels from locking up during braking, thereby maintaining tractive contact with the road surface abs is an automated system that uses the principles of threshold braking and cadence braking, techniques. Abs effectively supports truck drivers during braking maneuvers to help maintain the vehicles stability and steerability. Air brakes vehicles, trucks, buses, trailers and converter dollies built on or after march 1, 1998. The land rover discovery 2 comes with antilock braking system abs, traction control tc and hill descent control hdc as standard. Oct 02, 2017 the land rover discovery 2 comes with anti lock braking system abs, traction control tc and hill descent control hdc as standard. When driving a vehicle equipped with an antilock braking.
The main purpose of abs is to improve vehicle control under heavy braking, especially on loose or slick surfaces. Cdl vehicle inspection test in order to obtain a cdl you will be required to pass a. Antilock braking system abs absantilock braking system is a modern technology found on newer cars that allows the vehicle to be steered safely while braking hard. These braking systems are especially helpful during adverse weather. An antilock braking system abs is a safety antiskid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses.
For normal or emergency stopping using antilock brakes, the drivers foot remains on the brake pedal in which the antilock module then acts as a foot pumping the air brake system. Drive safely, because your anti lock brakes are only as good as the driver using them. Air brakes have five main components that work together to provide safe and effective braking for large vehicles. Abs helps you avoid wheel lock up and maintain control. The speed sensors, which are located at each wheel, or in some cases in the differential, provide this information. A vehicle with a gross vehicle weight rating of more than 26,000 pounds. You will be asked to do a vehicle inspection of your vehicle and explain to the examiner what you would inspect and why. But the new system when working like it should is the best ive ever seen for truck braking. It functions by preventing the wheels from locking up, which can result in uncontrollable skids. Also referred to as anti skid braking system sometimes, it enables the wheels of a vehicle to maintain tractive contact with the ground so that they.
Cdl practice tests cdl test answers cdl test questions. It offers an important safety advantage by preventing the wheels from locking during emergency braking situations, allowing drivers to maintain. Our combination vehicle practice tests contain questions that are nearly identical to the ones that you will see at the dmv. Abs antilock braking system computer, sensors and solenoid valves which together monitor wheel speed and modulate braking force if wheel lockup is sensed during braking. A driver should continue to drive and brake in a normal manner. Its a safety system that pulses the brakes many times per second so that they dont lock up. In order to drive a vehicle with air brakes, you must not only have practical experience and practice, but you must also pass the air brake test as part of your cdl to legally drive these vehicles. Abs anti lock brake system allows the driver to maintain better control of the car under hard braking. These cdl practice tests will cover questions regarding driving combinations safely, combination vehicle air brakes, anti lock brake systems, coupling and uncoupling, and inspecting combinations. Abs systems have selfdiagnostic capabilities to alert the driver if there is a problem in the system. Always pump the brakes several times before holding down. The antilock brake system should be serviced as soon as possible. The antilock braking system needs some way of knowing when a wheel is about to lock up.
Antilock braking systems commercial drivers license general. On the airbrake system the driver must pump or use stab braking in an emergency. It offers an important safety advantage by preventing the wheels from locking during emergency braking situations, allowing drivers to maintain control over steering and operate vehicles more effectively. Abs antilock braking systemis an automobile safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up that is, ceasing rotation and therefore avoiding skidding. When the brakes dont lock up, you are able to control the steering better. Abs brakes have been around trucks alot longer than cars. An antilock braking system or antiskid braking system abs is an automobile safety system that allows the wheels on a motor vehicle to maintain tractive contact with the road surface according to driver inputs while braking, preventing the wheels. Truck safety solutions antilock braking systems wabco. The reality of the abs system is that it allows the driver to maintain control over the vehicle while braking. When it fails it just goes back to your old braking system. Antilock braking systems cvsa commercial vehicle safety. Average rating from 205 customers who received a abs light is on inspection. The cdl general knowledge test covers several different sections. Paul is a 4wd defensive driver training consultanttrainer and programme developer.
Page 2 of the air brakes test study guide for the cdl. Abs works far faster than the driver can respond to potential wheel lockup. Abs stands for antilock braking system abs, and helps the tires on your vehicle to maintain contact with the road while you are braking. Dec 29, 2016 for background information on how anti lock brakes work, click here. There is a valve in the brake line of each brake controlled by the abs. The primary function of an antilock braking system is to. This content was developed by and owned by paul sinkinson, xplorability owner. A video about driving air braked trucks with abs antilock brake systems by the us dot.
If abs is not working, the basic braking functions on a vehicle will still remain, so the driver. The vehicle you are driving has anti lock brakes if. While you are driving, your vehicle constantly monitors sensors throughout the car to ensure everything works as intended. If you havent experienced abs antilock braking system brakes, try out those on. A commercial driver s license cdl is required by anyone who operates. It does not decrease or increase your normal braking capability. Jul 04, 2016 as the name signifies, the anti lock braking system is a safety system in cars and other automobiles that keeps their wheels from locking up and helps their drivers to maintain steering control.
During braking, if one wheel slows faster than the others and begins to lock, the module will signal solenoid valves in the hydraulic control unit to reduce fluid pressure to that wheel to prevent lockup. Fyi, the driver would also need to step on the brake pedal when braking a vehicle that is. The anti lock brake system should be serviced as soon as possible. Antilock brakes cannot compensate for driving faster, more aggressively, or maintaining unsafe following distances. Antilock braking systems have been a standard feature on vehicles for more than a quarter century. What a truck driver should know about antilock brake systems. When the brakes are applied, the abs senses when a wheel is about to lock and then releases just enough brake force to get the wheel rolling again while. If the anti lock brake system fails or malfunctions, the driver must resort to stopping the vehicle by using the normal airbrake method. If the light comes on and stays on, then the abs system is not working the braking system. Applying firm brake pressure, but not to the point of lockup d. It is designed to allow better control of a truck during hard braking. Helps the driver retain control of the vehicle during heavy braking on slippery roads. B abs allows you to drive faster, follow more closely, or drive less carefully.
When the brakes are applied, the abs senses when a wheel is about to lock and then releases just enough bra. Which of the following is true about antilock braking systems. There is a valve in the brake line of each brake controlled. Drivers when faced with an emergency situation inevitably slam on the brakes as hard as possible in a desperate attempt to stop the car in the shortest distance. The abs light comes on due to antilock braking system issues. When the abs is not needed, the brakes operate normally. Drivers who take and pass this test are eligible to drive vehicles that require a cdl permit and use an air brake system. Tips for driving with abs anti lock brake systems fourwheel abs is a safe, effective braking system when used properly. If the antilock brake system is not working, you should. If wheels lock, they lose that all important steering ability.
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