The Montana Department of Transportation (MDT) will begin a three-phase safety improvement project along sections of I 90 and I 15 in the Missoula, Butte, Bozeman, and Helena areas.
Built with safety in mind, high-tension cable rail will provide a flexible barrier made from steel cable mounted on steel posts in the center median. The high-tension cable rail is designed to reduce crash impact and redirect vehicles from crossing into oncoming lanes of traffic.
From start to finish, the Median High-Tension Cable Rail project will add high-tension cable guardrail across 150 miles of Montana’s roadways.
The first portion of the project will include 48 miles of median cable rail installation on I 90, west of Missoula near Wye, and continuing to exit 144 at Bearmouth. Contracts for additional sections of the project will be awarded later in 2022.
Construction will begin on the first section of the project will start in 2023 in the Missoula area. MDT estimates installation on the second phase of high-tension cable rail in the Butte and Bozeman areas will begin later in 2023. The third and final phase in the Helena area is anticipated for 2024.
Weekly updates will be provided throughout all phases of construction. To sign up for weekly updates, please send an email to
Frequently Asked Questions
Why is MDT using-high tension cable rail instead of the other types of guardrail I see across the state?
Cable railing is being used because of its extremely high efficacy rate of preventing fatal crashes and reducing the severity of crashes caused by vehicles crossing the median and into oncoming traffic.
Will there be any delays on the interstate because of this project?
Minor travel time delays are expected. Motorists should expect single lane closures and reduced speeds when passing through active work zones.
Why can’t all the work be completed at once?
To minimize impact to travelers, construction is divided into multiple projects that can be completed in a reasonable amount of time. The availability of materials and workforce are also considered when determining the scope of a project.
Funding also plays a pivotal role in how and when construction is completed. Each project requires funding that is derived from a variety of sources. Some projects are entirely federally funded, others are paid for with state funding, and many are a combination of federal and state funds. Before a construction project can begin, funding must be identified. Once funding is secured, the project is added to the construction schedule. This is done several years before the project goes to construction.
Why is there so much work concentrated in one area?
While not ideal for travelers, construction must often be completed during warm and dry weather. Since the warm months are few in Montana, MDT must complete many projects in a relatively short amount of time, resulting in several projects occurring at once and some projects being completed over multiple summers.
Occasionally, work will need to be completed on an emergency basis. Rockslides and extreme cases of erosion are examples of this. Emergency projects are addressed as quickly as possible. Sometimes the emergency work coincides with planned construction in the area. Since planned construction is scheduled years in advance, rescheduling is rarely an option, leading to co-occurring emergency work and planned projects.
UPN 9796000, 9797000 & 9839000.