DCA Controller described airport construction personnel crossing an active runway without authorization from the tower; no air traffic was involved.

Narrative

All positions were combined and also doing administrative duties. Airport Operations called Tower to ask if I had observed any vehicles crossing Runway 1/19; I stated no and that no alerts had gone off. Airport pulled video and said that a contractor dump truck without radios had crossed runway; no aircraft were involved; there was no air traffic. Called Regional Operations Center and Quality Control to inform and processed preliminary paperwork for vehicle deviation. Airport removed construction worker and removed his badge. We have a lot of construction at the airport during the overnight hours; the contractors are to be escorted. The contractors have minimal training to familiarize the drivers with the airport and airport layout and the importance of following the guidelines. The vehicle involved was unescorted and had no radios in the dump truck. The airport needs to do a better job of training these people; no aircraft were involved luckily. They need to show them what the runway markings mean and hold short lines and do a better job of familiarizing the workers with their surroundings.