SMA PLT TURNS ONTO RWY INSTEAD OF TXWY WHEN EXITING LNDG RWY.

Narrative

I WAS CLRED TO LAND ON RWY 27R. AFTER ROLLOUT I TURNED L ON RWY 17; MISJUDGING IT AS BEING A TXWY. ATC TWR ADVISED ME TO REMAIN ON TWR FREQ AND HOLD SHORT AT RWY 27L. SINCE I WAS NOT FAMILIAR WITH THE ARPT I CAUTIOUSLY CONTINUED TO TAXI TOWARD RWY 27L. SINCE THERE ARE NO HOLDING LINES ON RWY 17; I WAS READY TO STOP AT ABOUT 15-20 FT BEFORE MOVING ON TO RWY 27L. AT THE SAME MOMENT I STOPPED; 20 FT BEFORE REACHING THE EDGE OF RWY 27L; A LOW WING SINGLE ENG (TIGER?) WAS ON THE TKOF ROLL ON RWY 27L AND THE PLT WAS CONCERNED ABOUT ME TAXIING INTO HIS TKOF PATH. I CAN UNDERSTAND HIS CONCERN; BUT I ALREADY WAS AWARE OF HIS MOVEMENT AND I WAS READY TO STOP AT A SAFE DISTANCE; WHICH I DID. AFTER THE OTHER ACFT SAFELY TOOK OFF I WAS SWITCHED TO GND CTL; AND I GOT A CLRNC TO TAXI TO TRANSIENT PARKING. AFTER BEING ADVISED TO CONTACT THE ATC SUPVR; I CALLED THE TWR AND EXPLAINED MY REACTION AND MY PERCEPTION. I ADMITTED THAT I TAXIED ONTO RWY 17 SINCE I DID NOT SEE ANY RWY INDICATOR NUMBER. IT IS TRUE THAT THE BROKEN CTRLINE IS WHITE AND NOT YELLOW; HOWEVER; SUCH MARKINGS CAN BE CONFUSING; SINCE I FREQUENTLY LAND AT LONG BEACH (LGB) ARPT; AND RWYS AT LGB HAVE YELLOW AS WELL AS WHITE CTRLINES; AND NON-ACTIVE RWYS ARE FREQUENTLY USED AS TXWYS. I AM FULLY AWARE THAT IT IS MY RESPONSIBILITY AS PIC TO FAMILIARIZE MYSELF WITH THE ARPT OUTLAY; ESPECIALLY THE ACTIVE RWYS AND TXWYS. STILL I BELIEVE THAT POSSIBLE CONFLICTS COULD AND SHOULD BE PREVENTED IF ATC WOULD NOT ALLOW TO TAXI ON RWY 17 WHILE BOTH RWYS 27R AND 27L ARE BEING USED FOR TKOFS AND LNDGS; AND NO CLR INDICATIONS ARE PRESENT TO INDICATE RWY NUMBERS OR BOUNDARIES.