Welcome to the website for the Seward Highway: O'Malley Road to Dimond Boulevard project. The Alaska Department of Transportation and Public Facilities (DOT&PF) will use this site to keep you informed about project development. Please refer to this site for updates on the project, documents, announcements of public meetings, and to make a comment or suggestion.


Project Description

This is the third in a series of projects to improve capacity, safety, access, and connectivity on the Seward Highway between Rabbit Creek Road and 36th Avenue.

Current (35%) design includes the following proposed elements:

  • Expansion of the existing six-lane configuration from Dimond Boulevard south to O’Malley Road
  • Diverging Diamond Interchanges at O’Malley Road and Dimond Boulevard
  • Grade-separated undercrossing at Scooter Avenue/Academy Drive
  • Improved and new pedestrian and bicycle facilities.

These proposed improvements will:

  • Increase capacity at the O’Malley Road and Dimond Boulevard interchanges
  • Improve cross-corridor connectivity and Dimond Center retail district access for both pedestrians and vehicles
  • Add new non-motorized routes and improve existing routes throughout the project corridor.

This project will include public and stakeholder involvement and coordination with adjacent projects such as the Seward Highway: Dimond Boulevard to Dowling Road Project (DOT&PF, in construction) and the Academy/Vanguard Drive Traffic Circulation Improvements (Municipality of Anchorage [MOA] project).


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
  • Reduce conflicts between vehicles and pedestrians by signalizing all pedestrian crossings
  • Provide an easy-to-use route through the interchange for bicyclists and pedestrians


Aerial - Project Overview: (Click to enlarge)

Cross Section: (Click to enlarge)

DOT&PF and MOA Project Coordination on Academy Drive: (Click on image to enlarge)

Draft Academy Drive Roadway Section: (Click on image to enlarge)
Interchanges - 35% Design: (Click on image to enlarge)

Diverging Diamond Interchange

O'Malley Road
Diverging Diamond Interchange


Video Links Illustrating DDIs


Other Links



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 segment from Tudor Road to Dowling Road was completed in 2013. Design of the Dowling Road to Dimond Boulevard segment is complete and construction is anticipated to start in 2017.  The segment from O’Malley Road to Dimond Boulevard is the next to enter the detailed design phase.

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. At this time, construction is projected to cost approximately $80-100 million.