Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 6.0
Situational Awareness; Confusion
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Air Traffic Control Separated Traffic
Airport; Aircraft; Human Factors
While working Local 1; Aircraft X was issued instructions to hold short of the runway. The pilot read back hold short instructions correctly but still attempted to cross. I observed the error and reiterated the hold short instructions. At this time Aircraft Y was rolling for departure. Aircraft X did stop however the aircraft crossed the hold short line the proximity was 297 feet to Aircraft Y departing at top speed.  I believe the hold short lines are confusing at this location. This particular occasion could be a clear case of expectation bias.
An aircraft acknowledged instructions to hold short of a runway but attempted to cross the runway anyway. The aircraft crossed the hold short line.