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Project # CFHWY00012 / Federal # 0537(008)


Background and Project History

Between 2001 and 2007 the DOT&PF conducted an Environmental Assessment on the environmental impacts of making improvements to the Seward Highway in Anchorage. The analysis resulted in an Environmental Assessment – Finding of No Significant Impact that was signed by the Federal Highway Administration in February 2007. Preliminary engineering determined the highway should be improved in sections. Design and construction of the segments from Tudor Road to Dowling Road and Dowling Road to Dimond Boulevard were completed in 2013 and 2018, respectively.

Purpose and Need

The purpose of the proposed action is to construct improvements to the Seward Highway corridor between Rabbit Creek Road and 36th Avenue to address current and future travel demands and mobility needs. The improvements provide additional capacity, connectivity, and safety enhancements. Existing peak-hour congestion in the study area is expected to worsen, as indicated by the regional growth and economic development projections described in Anchorage 2020: Anchorage Bowl Comprehensive Plan (MOA, 2001) and the Anchorage Bowl 2025: Long Range Transportation Plan (MOA, DOT&PF, and Anchorage Metropolitan Area Transportation Solutions [AMATS], 2007). Upgrades and additional connections to the Seward Highway will provide needed capacity to meet the travel demands generated by growth in the region.


It is anticipated that more than 90% of the funding for the Seward Highway: O’Malley Road to Dimond Boulevard Project will be federally funded and developed in accordance with Federal Highway Administration (FHWA) guidelines.

What's a Diverging Diamond Interchange?

Diverging Diamond Interchanges (DDI) are an innovative, proven solution for improving safety and mobility at interchanges. DDIs have been shown to:

  • Reduce delay and increase capacity in interchanges
  • Improve safety by removing opposing traffic for all left and right turn movements
  • Provide an easy-to-use route through the interchange for bicyclists and pedestrians