Narrative:

Aircraft #1 was cleared to taxi to runway 28L by ground control. Air carrier traffic was on a 5 mi final to runway 28L. Aircraft #1 passed the runway 28L hold short sign and taxied onto runway 23. As soon as I noticed, I called and instructed the pilot to hold position. The pilot acknowledged and stopped. Just over 1/2 of his aircraft extended beyond the hold short line. Since there was ample clearance (more distance existed from the nose of the aircraft to runway 28L than at any other runway 28L hold short line) I allowed the other aircraft to land on runway 28L. There was no traffic landing or departing on runway 23. The pilot advised that he expected to find runway 28L hold short signs on runway 23. The pilot would not have seen any hold short signs (or line) where he expected as the hold short signs for runway 28L and runway 23 are coincident. It is my belief that the signage in this area is confusing. If this signage meets minimum FAA standards, I believe these standards are flawed, as I have observed numerous occasions of similar pilot blunders at this intersection. I have even seen a king air pilot attempt takeoff on runway 23, thinking it was runway 28L.

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Original NASA ASRS Text

Title: PLTDEV WHEN AN ACR CROSSED THE COMMON HOLD SHORT LINE FOR RWY 23L AND RWY 28L AND TAXIED ONTO RWY 23L.

Narrative: ACFT #1 WAS CLRED TO TAXI TO RWY 28L BY GND CTL. ACR TFC WAS ON A 5 MI FINAL TO RWY 28L. ACFT #1 PASSED THE RWY 28L HOLD SHORT SIGN AND TAXIED ONTO RWY 23. AS SOON AS I NOTICED, I CALLED AND INSTRUCTED THE PLT TO HOLD POS. THE PLT ACKNOWLEDGED AND STOPPED. JUST OVER 1/2 OF HIS ACFT EXTENDED BEYOND THE HOLD SHORT LINE. SINCE THERE WAS AMPLE CLRNC (MORE DISTANCE EXISTED FROM THE NOSE OF THE ACFT TO RWY 28L THAN AT ANY OTHER RWY 28L HOLD SHORT LINE) I ALLOWED THE OTHER ACFT TO LAND ON RWY 28L. THERE WAS NO TFC LNDG OR DEPARTING ON RWY 23. THE PLT ADVISED THAT HE EXPECTED TO FIND RWY 28L HOLD SHORT SIGNS ON RWY 23. THE PLT WOULD NOT HAVE SEEN ANY HOLD SHORT SIGNS (OR LINE) WHERE HE EXPECTED AS THE HOLD SHORT SIGNS FOR RWY 28L AND RWY 23 ARE COINCIDENT. IT IS MY BELIEF THAT THE SIGNAGE IN THIS AREA IS CONFUSING. IF THIS SIGNAGE MEETS MINIMUM FAA STANDARDS, I BELIEVE THESE STANDARDS ARE FLAWED, AS I HAVE OBSERVED NUMEROUS OCCASIONS OF SIMILAR PLT BLUNDERS AT THIS INTXN. I HAVE EVEN SEEN A KING AIR PLT ATTEMPT TKOF ON RWY 23, THINKING IT WAS RWY 28L.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.