Which of the following is the correct procedure for testing the parking brake before driving?

Test the parking brake by setting it, placing the vehicle in a low gear, releasing the clutch slowly with the engine running, and gently increasing power. The parking brake should hold the vehicle in place; if the truck rolls or creeps, the parking brake is defective and the vehicle must not be driven. This test must be done in a safe location away from anything you might roll into. Letting a vehicle roll on a flat surface only verifies that the brake holds against gravity, not against engine torque. Starting the engine in gear is dangerous and not a test procedure. The parking brake (which is spring-applied and air-released on a heavy commercial vehicle) is independent of the service brakes and must be tested separately each day.