Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 120; Flight Crew Total 6000; Flight Crew Type 400
Confusion; Situational Awareness; Communication Breakdown; Time Pressure
Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Other / Unknown; Ground Incursion Runway
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert
Airport; Human Factors; Procedure
On the ground at OAK we were cleared to taxi on C to cross 28R and 28L at B. We were told to expedite our taxi due to an airplane on a four mile final. At the runways; the signage was unclear and we could only see c and a signs. My copilot had me turn onto the taxiway between the two signs thinking it was bravo; and the ground controller told us we had turned on A. He asked if we had crossed the hold short line; my copilot mistakenly answered no and he told us to hold our position. Immediately my First Officer restated our correct position and the controller told us to continue our taxi and requested the aircraft on final to go around.After we continued on A; we could then see the B sign to our right. Because of its placement between the two runways; it's not immediately visible from C unless you turn 90 degrees and face perpendicular to the runway. It is maybe 100 yards away from where you would expect it to be so it's not surprising that the supervisor advised they see problems like what we experienced a thousand times a year; and are hopeful to get better signage.
The Cessna missed B at Runway 28R (due to poor/no signage to indicate B) and crossed the hold bars of RWY 28R at A while a twin Cessna was about 1.5 miles out on final on a visual approach. To [significantly] reduce the possibility of this scenario and more serious ones like this from occurring I think a raised 'Taxiway B' sign would improve the chances of this happening a lot less.
When a Citation flight crew was cleared to cross runways 28R and L at OAK on B they mistakenly turned on A.  The flight crew and the Ground Controller agreed that poor signage was the major contributing factor; the Controller stating they see similar events 'a thousand times a year.'