Date: 201502
Local time of day: 0001-0600
Location: IAH.Airport, TX
Flight conditions: VMC
Light: Night
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower IAH
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown; Ground Excursion Taxiway; Ground Incursion Taxiway
Detector: Person Flight Crew
When detected: Taxi
Result: General None Reported / Taken
Contributing factors: Airport; Human Factors
Primary problem: Human Factors

Narrative: We pushed off the gate and I suggested we do all our pre takeoff checks before we headed to runway 15L which is very close to our gate. We elected not to do so and upon nearing 15L we were asked by tower if we were ready for takeoff; we said we needed a minute. We taxied via WW to the hold area. We accomplished our pre takeoff checks and informed tower we were ready for takeoff; an aircraft had just taken off 15L via taxiway WV. I read the line up and wait clearance for 15L and looked down to finish off the mechanical checklist. I looked up and saw BLUE lights; I said ' Stop; blue lights'. The Captain (CA) preceded to taxi across WW onto WV; this area was marked off by the taxiway edge lights (BLUE lights); on crossing ground asked where we were since he said he lost us; A plane behind us said 'you have enough spacing to proceed forward'; that put us onto WV. Ground asked that crew if he should send someone out to look for any damage to BLUE lights; he said 'negative; he got across just fine'. We lined up and took off from 15L at WV when we should have done it at WW. I only saw one BLUE light out of the corner of my right eye; it was nighttime and it would have been nice if that particular area were better lit. I wished we would have done all our pre takeoff checks after pushback; there was not a lot of traffic and would have reduced our workload and made us not have to stop; we did find WW right away. The CA commented he went straight after we left the hold area because he saw a plane take runway 15L and takeoff; he mistook WV for WW since it's a tight turn from the hold area at WW onto 15L; he blew right through WW onto WV and I caught it as he was inches from crossing WW onto WV. I should have increased the volume of my voice when I said 'Stop; BLUE lights'; he did hear me but must have been deep in thought. This happened in my opinion because it was nighttime; not much experience at this airport; first time flying with this CA; not enough lighting to distinguish the boundary between WW and WV; tight turn from the hold area to 15L (at night); the illusion of the previous aircraft being right in front of us taking 15L (which he did but via WV; seemed very close at night as if he were on WW.  Most importantly I should pay extra attention as if I were the one taxing since it was nighttime and we had deviated from a normal taxi sequence by having to go to the hold area.  I should have read back 'line and wait 15L via WW and looked for the WW markings. My awareness meter has now gone up tenfold on all nighttime taxiing and communication will be top priority as far as talking about how we are lining up on an active runway.




Synopsis: First Officer describes a night time taxiway excursion at IAH after being cleared into the holding pad at the approach end of Runway 15L to complete checklists. When cleared to line up and wait on Runway 15L the Captain taxis straight ahead across Taxiway WW and the island separating WW from WV. The island is all concrete and no taxiway edge lights are hit.