Air Brakes #1
Air Brakes Endorsement Test | Colorado 2026 #1 Page 3 of 4
Train for FREE online with our Colorado CDL air brake test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a CO Class A/Class B driver license in 2026, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that the requirements for CDL may vary from state to state.
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13 . If the brake pads rub against the brake drums and create too much heat:
The air compressor will kick on to cool the brakes.
Brakes heat up with use. If they are overused and become too hot, expansion and chemical changes will make them less effective and eventually cause them to stop working altogether. This is known as "brake fade."
14 . If the low pressure warning light comes on while you are driving:
You should continue driving, but turn the emergency flashers on to warn other motorists.
If the low air pressure warning light turns on, you should stop and safely park your vehicle as soon as possible. Controlled braking will be possible only as long as enough air remains in the tanks.
15 . What can happen if the air pressure gets too low in an air brake system?
The brakes will be very sensitive.
Pressing and releasing the brake pedal unnecessarily can let air out faster than the compressor can replace it, reducing the available air pressure. If the air pressure in an air brake system gets too low, the brakes will no longer work.
16 . During an applied leakage test, the maximum leakage rate for a single vehicle with air brakes is:
4 psi in one minute.
It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.
17 . Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when:
Driving uphill.
Before driving a vehicle with air brakes, you should ensure that the spring brakes come on automatically when air tank pressure falls to a level between 20 and 45 psi. You can do this by chocking the wheels and releasing air from the braking system by stepping on and off the brake pedal. Once the pressure drops to an unsafe level, the parking brake valve should pop out and spring brakes should come on.
18 . Dollies equipped with ABS are required to have malfunction lamps located where?
On the top
A dolly equipped with an Anti-Lock Braking System (ABS) is required to have a yellow malfunction lamp located on its left side.
2026 Colorado | Frequently Asked Questions
To secure a CDL Doubles/Triples endorsement in Colorado, you must already hold a valid CDL. You'll need to pass a knowledge test on handling large trucks with multiple trailers. After passing, the endorsement will be added to your CDL. Remember, this endorsement does not cover the operation of motorcycles or school buses.
To obtain a Colorado CDL Doubles/Triples license, you should first have a valid Colorado CDL. Then, you'll need to pass the Doubles and Triples endorsement test. This test covers topics like coupling and uncoupling, inspecting doubles and triples, and handling. After passing the test, the endorsement will be added to your CDL.
While Colorado doesn't specifically require specialized training for a CDL Doubles/Triples endorsement, it's highly recommended. Training can ensure you're prepared for the knowledge test and safe operation of these vehicles. Experience driving a single trailer truck may also be beneficial, but isn't required. The key requirement is passing the endorsement knowledge test.
Yes, to obtain a CDL Doubles/Triples endorsement in Colorado, you must pass a written knowledge test. This exam focuses on the safe operation and handling of large trucks with multiple trailers. It's important to study thoroughly, using resources like the Colorado CDL Handbook, to ensure success on this test.
For the CDL Doubles/Triples endorsement in Colorado, you're not required to perform a skills or road test. The endorsement solely requires passing a written knowledge test. This test covers topics like coupling and uncoupling, inspecting doubles and triples, and managing the vehicles on the road. Practical skills are important for safe driving but aren't formally tested for this endorsement.
No, it is not permissible to operate double or triple trailers in Colorado without a valid CDL Doubles/Triples endorsement. This endorsement is necessary to ensure that drivers have the specialized knowledge and skills required to safely operate such vehicles. Driving without the proper endorsement can result in legal penalties.
In Colorado, you can add the CDL Doubles/Triples endorsement to your existing commercial driver's license. You don't need to initiate a new application for a separate license. However, you must pass the written knowledge test specific to doubles/triples operation. After passing, the endorsement is added to your current CDL.
Yes, even with a CDL Doubles/Triples endorsement, Colorado drivers must adhere to specific rules. These include a maximum trailer length of 28.5 feet for each unit in a set of doubles, and the total weight of all units combined cannot exceed 80,000 lbs. Also, drivers must follow all federal and state transportation laws, including hours of service regulations.
In Colorado, the maximum legal weight for a vehicle, including double or triple trailers, is 80,000 pounds. The maximum length for a single trailer is 57 feet 4 inches. For double/triple trailers, the combined length should not exceed 100 feet. However, these restrictions may vary depending on road and bridge limits.
Yes, safety is paramount when operating double/triple trailers. Drivers must follow federal and state laws, including speed limits and hours of service regulations. They should also be well-versed in coupling and uncoupling procedures, inspecting the coupling system regularly. Additionally, they must understand the high rollover risk associated with these vehicles and ensure proper cargo distribution to prevent accidents.