After coupling a doubles combination, what verification should be performed before driving?

Verification of a complete doubles coupling involves multiple checks: (1) tug test on the tractor-to-lead-trailer fifth wheel coupling; (2) tug test on the dolly-to-rear-trailer fifth wheel coupling (pull against each kingpin to verify engagement); (3) visual inspection of the pintle hook with safety chains/cables; (4) air and electrical line connections at every coupling point checked for proper seal and operation; (5) brake test using the trailer hand valve and the foot brake to verify all trailers brake correctly; (6) low-pressure warning and spring brake tests as on any combination. Skipping any check risks a catastrophic failure on the road.