Air carrier flight crew reported accidentally taxiing onto a service road at DEN airport in low visibility conditions and cited as a contributing factor a lack of signs or markings indicating this pavement is not a taxiway.
Synopsis
Air carrier flight crew reported accidentally taxiing onto a service road at DEN airport in low visibility conditions and cited as a contributing factor a lack of signs or markings indicating this pavement is not a taxiway.
Narrative
After landing on RWY 34R and exiting; we were given the Freeze route to taxi to XX gate. On taxiway Z; we were given further instructions to taxi L; BS to our gate. Approaching taxiway L; the Captain began a right turn onto what he thought was the correct taxiway. We realized that we accidentally turned onto a service road. We stopped and notified ground of the error. They sent ground ops vehicles to where we were on the service road; and we established comms with them. The tail of our aircraft was still blocking taxiway Z as we had only gone about 30 feet into the service road (enough to not be able to turn back to the correct taxiway). Ops had us pull forward so aircraft could taxi behind us on Z. The Captain made passenger announcements and I monitored ground and talked to ops. After about 30 mins of waiting; the tug met us and we opened the main cabin door so they could come onboard and communicate their plan. We shut engines down and they tugged us to the gate. Passengers got off; and it was uneventful after that. Visibility was low and taxiway markings were obscured by snow. It wasn't until we had turned that we realized we were on a service road. The captain was momentarily confused by taxiway L signage. Clearing the taxiways better; Do not enter" sign near service road; paying better attention to taxiway blue lights; verbalizing where we are taxiing"
Second reporter narrative
After landing on RWY 34R and exiting; we were given the Freeze route to taxi to our gate. On taxiway Z; we were given further instructions to taxi L; BS to our gate. Approaching taxiway L; I began a right turn onto what I thought was the correct taxiway. I quickly realized that I had inadvertently turned onto the service road (based on the markings not being taxiway markings and service vehicles approaching the aircraft). I brought the aircraft to a stop and we notified ground of the error. They sent 2 ground ops vehicles to our location and we established comms with them. The tail of our aircraft was still blocking taxiway Z as we had only gone about 30 feet into the service road (enough to not be able to turn back to the correct taxiway). Ops had us pull forward a short distance so the 2-3 aircraft on Z could pass by which they did after we moved. After making a couple of passenger announcements; a tug met us and we opened the main cabin door so they could come onboard and communicate their plan. We shut our remaining engine down and they tugged us to the gate. There were several upset passengers as they likely missed their connecting flights.The taxiway was partially obscured by compacted snow which made identifying the correct path more difficult. I also was momentarily confused when I glanced over and saw the 'L' sign by the service road after I realized I wasn't where I wanted to be which resulted in us going slightly further into the service road.If there was signage identifying it as a service road that would help; since the road itself is easily wide enough to be a taxiway and the markings were somewhat obscured by compacted snow. Additionally; if the taxiway was more thoroughly cleared; it would have made identifying the correct taxiway easier. Maintaining a slower taxi speed would have given us more reaction time as well. Ultimately paying attention to the other cues (especially the blue taxiway lights) would have helped avoid the misidentification.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.