Small Aircraft; High Wing; 1 Eng; Fixed Gear
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) .9
Distraction; Confusion; Situational Awareness; Workload
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Became Reoriented
ATC Equipment / Nav Facility / Buildings; Airport; Human Factors; Procedure; Aircraft
Traffic volume was beginning to slow after a departure and arrival push with weather to the west of the airport. I had two IFR departures left to depart with two aircraft on final.  Local Control 2 had landed a Aircraft X and was waiting in between the runways; on taxiway Golf; to cross Runway 16R for after two departures. We coordinated the crossing to occur after the Aircraft Y departure about 3 minutes prior. The IFR Aircraft Y was at rotation passing Taxiway Foxtrot and the first final Cherokee was on a 1 mile final when Aircraft X requested a right downwind departure. I scanned the runway and cleared the Aircraft Z for takeoff without delay traffic on a 1 mile final. I was alerted to the crossing when the bonanza was crossing the hold bars and gave alternate instructions to cross Runway 16R and hold short of Runway 16L. Aircraft Z did not take the instructions and continued to maneuver for takeoff Runway 16R and I cancelled takeoff clearance and instructed Aircraft Z to turn right at taxiway Delta; in which they complied. When I was scanning the aircraft at Golf was not visible. Taxiway Golf is blocked by the Radar screen and the support beams for the tower. I was trying to hit a departure hole between the arrival and departure to not delay the Aircraft Z to have to wait for the aircraft on 4.5 mile final.Cross Aircraft Z to depart Runway 16L. Move Local Control 1 and Local Control 2 to different positions to eliminate blind spots.
An aircraft was instructed to hold short of a runway. The aircraft disregarded the instruction and entered the runway. The controller's views toward that particular direction are blocked by a radar display and support beams causing a delay in the Controller noticing the runway incursion.