The safety improvements will help persons using the Tammany Trace get across the busy highway by entering a long tunnel that goes below the highway. The highway will also be re-aligned to produce a smoother S-curve. The highway in that area is bordered by several commercial/industrial driveways.
A tunnel was built under U. S. 190 in Mandeville in 2001 to handle Tammany Trace traffic going through that area. Click on the images to make them larger.
The U.S. 190 Tammany Trace tunnel in Mandeville
The new tunnel, Highway Project H.010184, was bid out by the State of Louisiana - Department of Transportation and Development (DOTD), with Meyer Engineers, Ltd. designing and providing project management for the planned Tammany Trace tunnel under LA 59.
A portion of the highway plans layout for the Tammany Trace tunnel. The tunnel is shown going from side to side at a slight angle in dark cross-hatching. West is at the top.
According to the department, the project will remove the existing, dangerous at-grade crossing between the Tammany Trace and LA 59 by routing traffic on the Trace under LA 59 with a 150 foot long tunnel. The tunnel will include approach ramps, a sump pump to keep the tunnel dry, lighting, and waterproofing. An at grade crossing with LA 59 will be maintained to allow access to the Trace from LA 59.
This view, with west at the top, shows the old existing road in light outline, and the new roadway with connecting side roads in dark lines. Business driveways are seen also in light outline. Turning lanes may also be a part of the roadway.
The "S" Curve
"Additionally, the project will improve LA 59 by straightening the existing sharp "S" curve left behind from when the Tammany Trace was a railroad.
This part of Tammany Trace soon to be underground
A close up of plans for the tunnel cross-section
Equipment on site to relocate overhead powerlines
. This project is part of a Cooperative Endeavor Agreement (CEA) between St. Tammany Parish and LA DOTD. Overall the project may cost close to $4 million.
The Mandeville Tammany Trace Tunnel
Tracing the Old Railroad