South Carolina CDL Permit Test - Double

Number of questions: 20
Passing score: 16
Directions: This endorsement is required if the driver will pull two or three trailers. To receive this endorsement, applicants must pass a test. The test consists of 20 multiple choice questions. To pass, the applicant must answer at least 16 questions correctly. Each question has two, three or four possible answer choices. Test questions come from the South Carolina Commercial Driver License Manual. Questions come from chapters covering: Driving Safely, Air Brakes (if applicable), Combination Vehicles and Doubles and Triples. The Double/Triple endorsement can be used with the Class A CDL.
You have made error so far
Passing grade —
4 or fewer errors
When driving, space is:
Not encouraged between vehicles
A safety cushion, allowing time if something goes wrong
Only encouraged on the passenger side of the vehicle
How is the parking brake released?
By tapping on the brake pedal three times
Pushing in the brake control knob
The parking brake is automatically released when the vehicle is started
Tap the accelerator pedal twice
One tip to prevent becoming an aggressive driver is:
To talk on your cell phone
To question other people’s driving
To set realistic travel time, allowing for delays during the trip
Bent lock rings:
Are not a concern in dry weather
Are dangerous
Can lengthen tire life
What does ABS do?
Allows the wheels to lock up
Prevents wheels from locking up
Makes it easier to turn
Why do larger vehicles use air brakes?
Other brake systems will squeak too loudly
Air brakes are very effective systems
Air brakes are complicated
Air is free
To control a surge, when stopping:
Do not keep a steady pressure on the brakes
Try not to brake in advance of a stop
Do not release the brakes too soon
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