Wyoming Department of Transportation

Why is this Project needed?

In 2005, WYDOT prepared the US 89 Star Valley Corridor Study, to examine US 89 from Smoot to Alpine and formulate a strategy to improve and protect the ability of the highway to fulfill its intended function as a Rural Principal Arterial route in the future. With the increase in traffic due to the population growth and conversion of agricultural land to residential development within the entire Star Valley, US 89 between Etna and Alpine has been degraded in its ability to effectively and safely serve as a Rural Principal Arterial.  

Insufficient local road networks with insufficient access controls and the co-existence of agricultural equipment on the roadway, have also placed a strain on the operation of this highway; thereby reducing its functionality and efficiency as a Rural Principal Arterial for the Star Valley. 

Purpose and Need for Action

The overall purpose of this proposed action is to improve the highway to fulfill its intended function as a Rural Principal Arterial. Implementation of the proposed action should address the following U.S. 89 corridor needs:

  • Improve highway safety
    • Over a five-year period, this corridor has had more crashes than the state-wide average for similar roadways in Wyoming.  In addition, those crashes also tend to be more severe.
    • The safety index for U.S. 89 indicates a significant potential for safety improvement.  Download the Wyoming Safety Index for more information.
  • Provide a transportation facility with increased capacity and improved level of service
    • Level of Service is anticipated to degrade to where the functionality of the highway will be seriously compromised within 20 years
    • Average Daily Traffic is expected to increase by approximately 40 percent within 20 years
    • With the increase in traffic, a vehicle is anticipated to be forced to follow another vehicle for 70% of the time while traveling the corridor
    • Access points with in the corridor must be improved to provide satisfactory level of service, increase traffic flow, and improve safety
  • Improve roadway; alignment, intersections, and pavement structure
  • Increased traffic requires flattening of both vertical and horizontal curves to improve safety
  • Seven county roads intersect US 89 at six intersections:all intersections need improvement to accommodate increased traffic