46. The air leakage rate for a combination vehicle (engine off, brakes on) should be less than ____ psi per minute.
4
47. Compared to straight truck or bus there are ____ things to inspect in combination vehicle.
More
48. When checking the trailer emergency brakes the tractor protection control valve should be placed in what position?
Emergency
49. In normal driving, some drivers use the hand valve before the brake pedal to prevent a jackknife. Which of the statements is true?
It should not be done.
50. While checking if the trailer is securely coupled to the trailer the landing gears should be:
Slightly raised.