Narrative:

During the approach briefing we discussed a detailed taxi plan including the south side construction areas depicted on commercial airport chart. On the airport diagram we could see that from runway 25L the ap taxiway would take us to cross runway 25R at taxiway P and back track to spot. Txwys st and T were notamed closed so our next option was to go to the end of runway 25L and cross at taxiway U. It was the first officer's leg so he rigged for automatic brakes 3 and was determined to try for taxiway ap; which was very do-able. I had my airport diagram under the clip rather than the construction page because it was 4 months 'newer.' it also contained frequencys; notes and terminal/taxiway depictions...except the ones we needed. We ended up taxiing clear of runway 25L on taxiway an; which is not on airport diagram and not included in our taxi plan. Upon clearing the runway; tower cleared us to cross runway 25R; which I attempted to do from my position on taxiway an. I could see taxiway M on the other side of the runway and our parking terminal/spot so I went for it. At a point too late to stop due to aircraft momentum; I noticed I was taxiing between the taxiway lights nicely but I was taxiing over double yellow lines and a green painted concrete 'wedges.' the construction page does not depict the wedges. It makes it look as if taxiway an leads to taxiway M on the other side of runway 25R. This is not true. You have to taxi over double yellow boundaried green wedges to do it. The depiction on the airport diagram is a fair representation of the taxiway lighting; not concrete and paint. I have never before seen a taxiway green paint configuration like this before. Very confusing situation; plus I didn't have the tools (detailed current airport diagram) to make a good taxi plan. Callback conversation with reporter revealed the following information: the reporter described his commercial construction chart as the most accurate available and even that was not exactly correct because taxiing from taxiway 'an' off of runway 25L on to taxiway 'M' to cross runway 25R is not a straight line but requires a right turn followed by a left as the aircraft crosses taxiway 'AC.' there are double yellow lines with green borders that the reporter believes are meant to steer the aircraft away from taxiway M after crossing on taxiway an but because the markings are novel and he has never seen them before he did not understand. Fortunately the aircraft crossed safely.

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Original NASA ASRS Text

Title: A B737 CAPT REPORTS EXITING LAX RWY 25L AT TXWY 'AN' AND CROSSING RWY 25R ON TXWY 'M.' TWO TXWYS DO NOT LINE UP AND HAVE UNUSUAL PREVENTATIVE MARKINGS.

Narrative: DURING THE APCH BRIEFING WE DISCUSSED A DETAILED TAXI PLAN INCLUDING THE SOUTH SIDE CONSTRUCTION AREAS DEPICTED ON COMMERCIAL ARPT CHART. ON THE AIRPORT DIAGRAM WE COULD SEE THAT FROM RWY 25L THE AP TXWY WOULD TAKE US TO CROSS RWY 25R AT TXWY P AND BACK TRACK TO SPOT. TXWYS ST AND T WERE NOTAMED CLOSED SO OUR NEXT OPTION WAS TO GO TO THE END OF RWY 25L AND CROSS AT TXWY U. IT WAS THE FO'S LEG SO HE RIGGED FOR AUTO BRAKES 3 AND WAS DETERMINED TO TRY FOR TXWY AP; WHICH WAS VERY DO-ABLE. I HAD MY ARPT DIAGRAM UNDER THE CLIP RATHER THAN THE CONSTRUCTION PAGE BECAUSE IT WAS 4 MONTHS 'NEWER.' IT ALSO CONTAINED FREQS; NOTES AND TERMINAL/TXWY DEPICTIONS...EXCEPT THE ONES WE NEEDED. WE ENDED UP TAXIING CLEAR OF RWY 25L ON TXWY AN; WHICH IS NOT ON ARPT DIAGRAM AND NOT INCLUDED IN OUR TAXI PLAN. UPON CLEARING THE RWY; TWR CLEARED US TO CROSS RWY 25R; WHICH I ATTEMPTED TO DO FROM MY POSITION ON TXWY AN. I COULD SEE TXWY M ON THE OTHER SIDE OF THE RWY AND OUR PARKING TERMINAL/SPOT SO I WENT FOR IT. AT A POINT TOO LATE TO STOP DUE TO ACFT MOMENTUM; I NOTICED I WAS TAXIING BETWEEN THE TXWY LIGHTS NICELY BUT I WAS TAXIING OVER DOUBLE YELLOW LINES AND A GREEN PAINTED CONCRETE 'WEDGES.' THE CONSTRUCTION PAGE DOES NOT DEPICT THE WEDGES. IT MAKES IT LOOK AS IF TXWY AN LEADS TO TXWY M ON THE OTHER SIDE OF RWY 25R. THIS IS NOT TRUE. YOU HAVE TO TAXI OVER DOUBLE YELLOW BOUNDARIED GREEN WEDGES TO DO IT. THE DEPICTION ON THE ARPT DIAGRAM IS A FAIR REPRESENTATION OF THE TXWY LIGHTING; NOT CONCRETE AND PAINT. I HAVE NEVER BEFORE SEEN A TXWY GREEN PAINT CONFIGURATION LIKE THIS BEFORE. VERY CONFUSING SITUATION; PLUS I DIDN'T HAVE THE TOOLS (DETAILED CURRENT ARPT DIAGRAM) TO MAKE A GOOD TAXI PLAN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER DESCRIBED HIS COMMERCIAL CONSTRUCTION CHART AS THE MOST ACCURATE AVAILABLE AND EVEN THAT WAS NOT EXACTLY CORRECT BECAUSE TAXIING FROM TXWY 'AN' OFF OF RWY 25L ON TO TXWY 'M' TO CROSS RWY 25R IS NOT A STRAIGHT LINE BUT REQUIRES A RIGHT TURN FOLLOWED BY A LEFT AS THE ACFT CROSSES TXWY 'AC.' THERE ARE DOUBLE YELLOW LINES WITH GREEN BORDERS THAT THE REPORTER BELIEVES ARE MEANT TO STEER THE ACFT AWAY FROM TXWY M AFTER CROSSING ON TXWY AN BUT BECAUSE THE MARKINGS ARE NOVEL AND HE HAS NEVER SEEN THEM BEFORE HE DID NOT UNDERSTAND. FORTUNATELY THE ACFT CROSSED SAFELY.

Data retrieved from NASA's ASRS site as of May 2009 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.