PA-31 Navajo/Chieftan/Mojave/T1040
Air Traffic Control Fully Certified
Distraction; Situational Awareness; Workload
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
General None Reported / Taken
Procedure; Human Factors; Staffing
Working Local Control; the 'hot box' on the strip board had the runway unusable 'flipper' was down for Runway 2R. Vehicle X was working the intersections of Runway 2R and approved on the runway. I was working a PA-18 in the pattern for the 'Ski Strip' and; in order to do so; you pretty much ignore the 'unusable' indication of the 'flipper' because that portion of the hotbox is a 'shared' area for both Runway 2R and Ski Strip 2. A PA-31 called me ready for Runway 2R; and I was just in the habit of looking out the windows following my PA-18 around; and I didn't look at the 'hotbox.' I cleared the PA-31 for takeoff and a few seconds later; Vehicle X called me on the radio saying he was exiting Runway 2R.  I had verified Vehicle X was holding short prior to the PA-31 beginning takeoff roll; but had Vehicle X not heard me clear the PA-31 for takeoff and exited on his own; nothing was done to prevent the PA-31 from taking off with a vehicle approved on his runway.I should have scanned my 'hotbox' before clearing the PA-31 for takeoff. If there was some way to de-combine the hotboxes for Runway 2R and Ski Strip 2 that would be helpful in preventing a repeat occurrence; however I do not see a practical way of doing that.
Local Controller cleared an aircraft for takeoff on a runway on which he had previously cleared an airport vehicle. Vehicle cleared the runway after hearing Controller issue clearance to the aircraft.