The new lighting system includes meters mounted atop exterior poles the entrance to each tube. The meters monitor the luminescence on the face of the portal and automatically adjust the brightness of the tunnel lights to one of five different levels, depending on the amount of ambient light on the face of the tunnel portal. Previously, the brightness of the interior lights was set manually to one of three lighting levels.
The intent is to reduce what is called the "black hole effect," the term for the harsh adjustment drivers’ eyes have to make as they move from brightness to darkness as vehicles enter the tunnel. The new fixtures are brightest and closest together at the entrances so that the adjustment is gradual.
The new lighting system is expected to be more efficient, producing more light at the same level of energy consumption as the fluorescent system. At certain levels, the new fixtures produce six times as much light for the same amount of power consumption.
The new fixtures will require less maintenance because they are sealed (and can be spray washed) and because the lamps inside the fixtures will have a longer life than the previous lamps.
Other aspects of the improvement project included repairs to the ceiling slabs and installation of netting to protect the roadway from falling chips, new piping to address ongoing groundwater seepage, an upgrade of the tunnel’s electrical distribution system, and four new diesel-powered generators to replace the old turbines that constituted the tunnel’s backup power system.
Design engineer Jim Stump said groundwater entering the tunnel is a constant battle, as it is at most tunnels. "Groundwater in a tunnel is very hard to control," he explained. "You can push it to one place and it comes out another."
The Turnpike also purchased a new $109,000 wrecker for Tuscarora Tunnel. The old 1979 model had no wheel lift capability and local service was required for vehicle removal. Tunnel Guard Ken Bloom said typical removal times were 20 to 30 minutes for a car or light truck and one hour for a tractor-trailer.
"The wrecker is a vital piece of equipment," said Bloom. "When something happens inside that blocks traffic, you have to get to it quick."
The Farfield Company of Lititz, Pennsylvania. was the general contractor for the improvement project, which began in fall 1999. Professional Systems Engineering, LLC of Lansdale, served as the lighting design consultant and Gannett Fleming of Harrisburg provided design for the structural work. Construction costs totaled approximately $6.5 million.