B767-300 reports a taxiway excursion after landing on runway 7L at lax and exiting at B4. Concrete a...

Narrative:

Prior to landing at lax on runway 07L; the tower told us to expedite our exit from the runway. Upon normal landing; control of the aircraft was transferred to the captain at taxi speed. The captain initiated the first available left turn off the runway which appeared to be a 90 degree left turn instead of a high speed exit. The turn off was a reverse high speed exit that was a paved area with obscure markings that was actually not a taxiway but a roadway tunnel that runs under the airport. We did not realize this until we were committed to the turn and there appeared to be a blue taxi light in the middle of the pavement. It appears we straddled the light and the tower commented that it was ok and we continued to the ramp. It did not appear that we struck any light or lights in this process. We thought that by expediting our taxi instructions that we were helping the tower with inbound pacific traffic when all we did was enable the lax tower to clear a B747 to takeoff immediately on 25R. The tower also had a flight inbound from the pacific and was clearing that traffic to land on 7L. Both runways were being utilized during this event.

Original NASA ASRS Text

Title: B767-300 reports a taxiway excursion after landing on Runway 7L at LAX and exiting at B4. Concrete area over roadway tunnel is thought to be a taxiway.

Narrative: Prior to landing at LAX on Runway 07L; the Tower told us to expedite our exit from the runway. Upon normal landing; control of the aircraft was transferred to the Captain at taxi speed. The Captain initiated the first available left turn off the runway which appeared to be a 90 degree left turn instead of a high speed exit. The turn off was a reverse high speed exit that was a paved area with obscure markings that was actually not a taxiway but a roadway tunnel that runs under the airport. We did not realize this until we were committed to the turn and there appeared to be a blue taxi light in the middle of the pavement. It appears we straddled the light and the tower commented that it was OK and we continued to the ramp. It did not appear that we struck any light or lights in this process. We thought that by expediting our taxi instructions that we were helping the Tower with inbound Pacific traffic when all we did was enable the LAX tower to clear a B747 to takeoff immediately on 25R. The Tower also had a flight inbound from the Pacific and was clearing that traffic to land on 7L. Both runways were being utilized during this event.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	898089
Time
Date	201007
Local Time Of Day	0001-0600
Place
Locale Reference	LAX.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 7600 Flight Crew Type 500
Events
Anomaly	Deviation - Procedural Published Material / Policy Ground Excursion Taxiway

B767-300 reports a taxiway excursion after landing on runway 7L at lax and exiting at B4. Concrete area over roadway tunnel is thought to be a taxiway.