Iowa cdl Double - Test 2
Number of questions: 20
Passing score: 80%
Acceptable number of errors: 4
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 three possible answer choices. Test questions come from the Iowa 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.
To DMV Handbooks17. In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when air pressure drops to a level between:
A
√
20 and 45 psi.
B
×
75 and 105 psi.
C
×
50 and 65 psi.