Couple a tractor and trailer before rolling

Reinforce the FMCSA CDL coupling order. The landing gear is not raised until the fifth-wheel jaws, visual pin check, lines, and tug test are complete.

1. Chock the trailer wheels.
2. Confirm fifth-wheel jaws are open and the release handle is in the automatic lock position.
3. Match fifth-wheel height so the trailer will lift slightly.
4. Back under slowly until the jaws lock.
5. Tug-test in low gear against the trailer brakes.
6. Visually confirm the jaws are closed around the kingpin shank and there is no gap.
7. Confirm the locking handle and safety latch are locked.
8. Connect gladhands and listen for leaks.
9. Connect the electrical line.
10. Supply air and charge the trailer brakes.
11. Raise the landing gear fully and stow the crank.
12. Remove the chocks and recheck the coupling before rolling.