Medium Transport; Low Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 15.0
Situational Awareness; Confusion; Communication Breakdown
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
General None Reported / Taken
Airport; ATC Equipment / Nav Facility / Buildings; Human Factors
An airport vehicle requested permission to inspect runways. After asking the supervisor if it was OK to proceed with the runway inspection; and getting permission to begin; I instructed the vehicle to proceed on to one runway and hold short of an intersecting runway. The airport vehicle read back 'proceed onto runway XX and hold short of runway YYL; I'll report clear of all runways'. I then cleared a regional jet for takeoff on the intersecting runway. As the aircraft was beginning its departure roll; I noticed the airport vehicle was almost through the intersection of the intersecting runways. The 'Collision Alert' system did not activate and the airport vehicle was through the intersection while the aircraft was still approximately 6500 feet from the intersection. The aircraft was allowed to continue his takeoff roll; as I determined the airport vehicle was clear of the runway and that it was probably too late to abort the takeoff roll.  Airport vehicles need to pay closer attention while conducting runway inspections. We have gone to great measures to come up with procedures in the tower to prevent vehicle runway incursions. But they only work if the airport vehicles can follow instructions.
An airport vehicle inspecting a runway was cleared to proceed onto the runway; but to hold short of an intersecting runway. The vehicle acknowledged the instruction and an aircraft was given a takeoff clearance on the intersecting runway. The vehicle ended up going through the runway intersection while the aircraft was on its takeoff roll.