Greater Triangle Area Transportation Plan

Gallatin County has experienced significant growth over the past 40 years. The county has consistently outpaced the population growth of other Montana counties. This growth can be attributed to the evolving economies of the county’s largest cities, Bozeman and Belgrade, the continued expansion of Montana State University in Bozeman, and in-migration resulting from the high quality of life that the county offers. As Gallatin County continues to grow, it is important to understand growth trends to properly accommodate and prepare for the county’s current and future transportation needs.

The last regional county transportation plan was completed in 2007 with more recent updates completed for the urban areas of Bozeman and Belgrade. A new, comprehensive look at the transportation system in the growing suburban area was needed to understand system needs and investment opportunities over the next 20 years.

The Greater Triangle Area Transportation Plan (GTATP) provides a comprehensive and integrated strategy for transportation infrastructure and service improvements within the greater triangle area between Bozeman, Belgrade, Four Corners, and Gallatin Gateway. The GTATP focuses on strengthened roadway connections to facilitate safe and efficient travel between these quickly growing communities within the county. The plan addresses regional transportation issues, overall travel convenience, traffic safety, sustainability, funding, and multimodal connections. The GTATP includes recommendations for short-term improvements as well as long-term modifications and capital improvements to major roadways.

The GTATP serves as a guide for development of and investment in the region’s transportation system in a comprehensive manner. The GTATP was developed through a collaborative approach with county, state, and city staff, elected officials, and local residents. The plan provides a blueprint for guiding transportation infrastructure investments based on system needs and associated decision-making principles. The GTATP integrates previously completed planning efforts, includes detailed analysis of existing and projected transportation conditions, incorporates meaningful input from citizens and local officials, and provides a framework for future efforts within the context of state and federal rules, regulations, and funding allocations.

US Highway 93 (US 93) is an important highway corridor and supports local, regional, and nationwide transportation. The Ninepipe segment extends from Reference Post (RP) 40.0 to 44.5 south of Ronan, MT in Mission Valley. The corridor is situated in a highly sensitive ecological and cultural environment through federal and tribal lands designated for wildlife management, environmental protection, and cultural preservation. Improvements to the corridor are needed to address poor existing traffic operations, projected increases in traffic volumes, multiple safety concerns, and a lack of dedicated pedestrian and bicycle facilities.

Building from an alternative identified in previous environmental documentation, RPA worked collaboratively with the Montana Department of Transportation (MDT), the Confederated Salish and Kootenai Tribes (CSKT), and multiple environmental resource agencies to identify a feasible reconstruction concept that would optimize benefits and reduce impacts. The study evaluated geotechnical constraints, hydraulic considerations, wetland impacts, cultural influences, and right-of-way needs to evaluate improvement options in terms of impacts, construction costs, and feasibility considerations. Findings from this study will be used to assist MDT in project development decisions and will support a future environmental re-evaluation.