Small Aircraft
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 0.5
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway; Ground Incursion Taxiway
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure; Airport; Chart Or Publication
Aircraft X landed on Runway 28R. Aircraft X was given taxi instructions; 'turn left at Kilo; right Bravo; hold short of Runway 28L at golf.' Pilot gave a poor readback. Aircraft X then turned onto Kilo; stopped short of Taxiway Bravo and reported holding short of 28. I reiterated taxi instructions to turn right on Bravo and hold short of 28L at golf. The pilot turned on Bravo and gave another poor readback. Local Control asked Aircraft X to verify hold short of runway 28L at golf. Aircraft X then read back his hold short instructions. Aircraft Y was cleared for takeoff on Runway 28L. Before Aircraft Y started his takeoff roll; Aircraft X crossed the hold short bars on golf. Local Control told Aircraft X to hold position before Aircraft X got onto the runway. Local Control then cancelled Aircraft Y takeoff clearance. Then; Local Control crossed Aircraft X and Ground Control gave Aircraft X a brasher warning. Aircraft X taxied to parking and Aircraft Y departed shortly after without further incident. Pilots landing on Runway 28R frequently seemed to be confused about hold short bars and which runway or taxiway they are on. When aircraft exit Runway 28R at Kilo and are told to hold short of Runway 28L at Kilo; they will often stop at the hold short bars for Runway 28R instead of 28L. This can quickly block Runway 28R and make it unusable. Also; if aircraft are told to taxi on Bravo and hold short of Runway 28L at another taxiway; they often seemed to be unsure of how far down to go. Runway and taxiway signage might need to be reevaluated to reduce pilot confusion.
Tower Controller reported an aircraft did not follow taxi instructions and caused a runway incursion.