aterpster
what would you have done if IAD had a TRW in progress? what would you have done if you couldn't get approach/departure control if you went around?
There are so many what ifs...as I've said before, a maintenance vehicle on the runway would have required a clearance from ATC.
IF ATC wasn't answering the radio, the maintenance vehicle wouldn't go on the runway. They would probably drive to a telephone and call someone in the tower. Or the police. Or use their cellphone.
Other planes wouldn't be on the runway without a clearance awaiting takeoff,as I've mentioned there is a noise curfew and you can't takeoff at this time frame.
and, if someone had just landed without ATC clearance, they would have the CTAF on their radio and the inbound plane could speak and coordinate with them.