Steese Expressway / Johansen Expressway Interchange

Diverging Diamond Interchange

The Diverging Diamond Interchange (DDI) with temporary detour connection, with modifications developed following the Draft Environmental Assessment public comment period, will be constructed. The DDI remains the most efficient alternative for managing traffic while minimizing project impacts on private property. The DDI will significantly reduce delay for motorists at the Steese/Johansen intersection while improving pedestrian and bicycle safety through the use of reduced crossing distances and signalization of major crossing movements.

The Steese/Johansen project will enhance motorized and non-motorized mobility and user safety. The pathway connection will be constructed between Northside Boulevard and Farmers Loop Road Extension to provide enhanced bike connectivity between the Johansen Expressway and Farmers Loop Road separated paths. The project will close City Lights Boulevard north of the Lazelle Road intersection, terminating in a cul-de-sac near the Birch Hill Cemetery entrance. A noise analysis identified the potential need for noise walls along the east side of the Steese Expressway between Trainer Gate and the Johansen Expressway. The adjacent intersections of Farmers Loop Road/Steese Expressway and Old Steese/Johansen Expressway will receive minor optimizations to align with the new traffic pattern. The Final Environmental Assessment and Finding of No Significant Impact are available here.

Description of the Preferred Build Alternative

The DDI with detour connection was selected for construction because it will:

• Significantly decrease delay at the existing Steese/Johansen intersection.
• Provide an enhanced bicycle/pedestrian connection between the existing separated pathways on the Johansen Expressway and Farmers Loop Road.
• Provide a bypass route during construction to manage traffic.

The Project Visualization video was updated on May 5, 2020. Please note that the design is in progress, and therefore this video may not reflect the most current design.

Diverging Diamond Interchange.

A summary of the alternatives analysis and reasons for selecting the Diverging Diamond Interchange with temporary detour connection is available here.

An overview of the proposed project is available here. While the DDI design is relatively new to Alaska and appears confusing on paper, to the driver it will work like a regular diamond interchange (such as Geist Road/Parks Highway). The enhanced layout and signal coordination provided by the DDI means that it will operate better than the Geist Road/Parks Highway interchange, and will do so with fewer lanes and a smaller project footprint.