Tunnel proposed as alternative to Sandpoint bypass

The Sandpoint Public Works Committee has unanimously agreed to hold a special meeting this fall to discuss digging a 2,250-foot tunnel for U.S. 95 beneath this North Idaho town.

The tunnel is an alternative to a proposal to route the highway around the town, which some say is dangerous and will harm downtown Sandpoint’s waterfront ambiance. Both projects are intended to relieve traffic congestion.

“Most of (the tunnel) is hidden from sight and that’s the beauty of it,” Steve Potter, a member of Citizens for the Sandpoint Tunnel, recently told the city’s Public Works Committee.

Potter is a mechanical engineer. He contacted Hatch Mott McDonald, a Seattle-based company that specializes in building tunnels.

“Tunnels of this size, type and depth are quite common, and have been successfully constructed in many developed areas around the world,” Stephen Mauss, vice president of Hatch Mott McDonald, told Potter in a July 19 letter.

The company has built about 1,500 miles of tunnels around the world, including a tunnel beneath the Detroit River linking the U.S. and Canada.

The tunnel beneath Sandpoint would be made with twin tubes that could each hold two lanes of traffic. Emergency access, closed-circuit TV monitoring and lighting would also be installed.

“Engineers need to engineer safety into this project and that’s been done in this case,” Potter told city officials, the Bonner County Daily Bee reported.

Potter said the tunnel could be built without having to destroy buildings above the tunnel. Instead of digging a trench and then covering it, the new highway tunnel could be made with soft-ground boring technology and then have large-diameter tubes inserted.

Liz Sedler is executive director of the North Idaho Community Action Network, which opposes the bypass alternative. She said the tunnel has possibilities.

“In our view, his efforts have produced a feasible alternative that will efficiently and safely move through-town traffic through Sandpoint and connect with the Dover Highway, with the added bonus of removing truck traffic from the downtown core,” Sedler said.

The cost of the byway is estimated at $90 million. Hatch Mott McDonald said the tunnel is projected to cost about $100 million.