FREE CDL Combination Vehicles Practice Test Online | Colorado 2024 Page 3 of 3
Train for FREE online with our Colorado CDL combination vehicle 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 combination license in 2021, 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 DMV requirements for issuing a combination license may vary from state to state.
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15 . Trailers with low underneath clearance may be difficult to drive:
At the posted speed limit.
Railroad-highway crossings may be difficult to cross when pulling a trailer with a low underneath clearance. In particular, both low-slung units and single-axle tractors pulling long trailers are especially challenging to drive over raised crossings.
16 . If unsure if a trailer is equipped with ABS, you can:
Remove a tire and look for the ABS sensor on the axle.
Trailers and converter dollies built on or after March 1, 1998 are required to have Anti-Lock Braking Systems (ABS). This will be indicated by the presence of a yellow malfunction lamp. You can determine if older trailers have ABS by checking under the trailers for ECU and wheel speed sensor wires coming from the back of the brakes.
17 . Driving a combination vehicle ____ than driving a single vehicle.
Is safer in inclement weather
Driving a combination vehicle usually requires more skill than driving a single vehicle. Combination vehicles are generally longer and heavier than single commercial vehicles.
18 . After coupling, there should be ____ between the upper and lower fifth wheel.
Three inches of space
Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.
19 . A shut-off valve:
Should always be open.
Shut-off valves are used in air supply lines to control the passage of air from one trailer to another. The rear shut-off valve should always be closed to prevent air from leaving the braking system.
20 . Compared to other commercial motor vehicles, combination vehicles need more space on the road because they are longer and they:
Swerve more often.
