Project Introduction
The Montana Department of Transportation plans to reconstruct a portion of State Highway 78 in Carbon County. The proposed work is to reconstruct approximately 5.1 miles of the existing roadway from milepost 0.00 (the intersection with US Highway 212 in Red Lodge) to milepost 5.10.
This project will also include improvements to side slopes to increase safety, will address existing snow drifting problems, and will include a chip seal, new signing, and pavement markings. The completion of this project will greatly extend the functional life of the roadway and improve the safety of the traveling public.
What is the primary purpose of this project?
The reason this project is being constructed is to increase the safety of the route and to provide a long-term quality highway. The accident rate for this portion of the route is higher than average and the trend is single vehicle, off road crashes, especially at the sharp curves.
Numerous features of the highway need to be improved to meet today’s safety standards. There have been no major improvements to this highway since it was originally constructed to secondary highway standards in the 1930’s. This highway is now a State Primary Highway and in order to increase the safety of the route (and to reduce the accident rate) the project was nominated to be reconstructed.
What’s planned for the project?In order to achieve the goals of the project and increase the safety of the route, the existing roadway must be reconstructed. It will be brought up to current design standards as follows:
- The completed roadway will be widened and paved with a finished top width of 30 feet. Current design standards only require a width of 28 feet, but MDT is proactively preparing for future maintenance of the road. There is a possibility to reduce the top width to 28 feet in order to save up-front project construction cost.
- Adjust the horizontal alignment, including realignment of the sharp curves to larger radii, incorporating spiral transitions and proper superelevation, or “banking of the curves”.
- Adjust the vertical alignment to meet current design standards for stopping sight distance. Grades will also be adjusted.
- Flatten adjacent side slopes to meet current design standards.
- Realign intersecting county roads for improved safety.
The following aerial photo shows the alignments that are being planned by MDT.
Click on an area of the map to zoom in for a closer look.
