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CDL Practice Test
General Knowledge
Air Brakes
Combination Vehicles
Doubles and Triples
Tanker Vehicles
Hazardous Materials
Transporting Passengers
CDL Practice Test
Question 1 of 3
Dual parking control valves are used in which of the following circumstances?
A
When air pressure is at its maximum
B
During routine operation
C
While parked
D
During emergencies
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