Montana Department of Transportation

What is the Boulder - South Environmental Assessment?

A portion of Montana State Primary Route 69 (MT 69) south of Boulder, in Jefferson County, has been nominated for reconstruction. This proposed project would widen the existing MT 69 alignment from MP 31.8± to MP 37.5± and correct several horizontal and vertical curve deficiencies while attempting to minimize impacts to affected social, economic, and environmental resources, including the Boulder River, wetlands, and irrigation facilities.

Where is the project located?

The proposed project is located in Jefferson County on MT 69. It begins at MP 31.8± and extends to the north approximately six miles, ending at MP 37.5± just south of Boulder.

As shown in the figure below, the proposed project is located within the following legal description(s):

Township	Range	Section(s)
5 N	3 W	18, 19
5 N	4 W	2, 3, 4, 10, 11, 13, 14, 24
6 N	4 W	32, 33

Purpose of the Project

The purpose of reconstruction of MT 69 is to improve safety for users of the project corridor while mitigating project impacts to the surrounding built and natural environments.

Need for the Project

A preliminary review of the existing horizontal and vertical alignment of the roadway indicates that improvements in the roadway design could provide substantial safety improvements in the corridor.

As shown in Table 1.1, the all-vehicle crash rate for the portion of MT 69 from MP 31.8± to MP 37.5± over the period January 1, 1997 through December 31, 2006 was approximately 1.59 times greater than the statewide average crash rate for rural state primary highway systems. Over the same period, the all-vehicle severity rate was nearly 1.24 times greater than the statewide average. Additionally, the percentage of crashes involving trucks over this portion of MT 69 was approximately 1.65 times the percentage of crashes involving trucks for all rural state primary highways over the same time period.

Table 1.1 Crash History Comparison

Criteria	Rural State Primary Highways (1997-2006)	MT 69 MP 31.8± - 37.5± (1997-2006)
Weighted AADT	NA	1,147
Total Number of Crashes	15,669	55
Crash Rate (All Vehicles)	1.45	2.30
Severity Index (All Vehicles)	2.41	1.89
Severity Rate (All Vehicles)	3.51	4.35
Total Number of Crashes Involving Trucks	1,209	7
Percentage of Crashes Involving Trucks	7.7%	12.7%
Snow, Slush, and Ice Pavement Conditions at Time of Crash (All Vehicles)	3,135	10
Dark Not Lighted at Time of Crash (All Vehicles)	4,921	18

Source: Montana Department of Transportation, 2008

Of all crashes that occurred during the period January 1, 1997 through December 31, 2006, nearly 73 percent (40 out of 55) involved single vehicles. Of these, 30 percent (12 out of 40) resulted in overturn. According to the May 2004 Preliminary Field Review Report (PFRR) prepared for this project, some factors contributing to this type of crash on MT 69 include narrow to non-existent shoulders, a sharp horizontal curve near MP 36.1±, and vertical crest curves that do not meet minimum Stopping Site Distance (SSD) guidelines. This safety improvement project would address these geometric features where practicable.

Conflicts with wild and domestic animals is another cause of crashes in the project corridor. Of all crashes over the period January 1, 1997 through December 31, 2006, nearly 35 percent (or 19 crashes out of 55 total crashes) involved collisions with animals. Of these 19 crashes, 37 percent (or 7 out of 19) involved domestic animals, while the remaining 63 percent (or 12 out of 19) involved wild animals. Widening the roadway’s top width, clearing side slopes, and making improvements to SSD in the corridor as proposed under this project may reduce the number of collisions with animals on MT 69.

Expected Schedule

The Montana Department of Transportation will manage the Boulder - South project and lead a team of consultants to complete the EA document by summer 2009. (Expected Project Schedule)