Seward Highway and Scooter Avenue/Academy Drive Roundabout Interchange

Abstract

The Alaska Department of Transportation and Public Facilities (AK DOT&PF) proposes the construction of a grade separated interchange at Scooter Avenue/Academy Drive along the Seward Highway. AK DOT&PF desires to build a roundabout interchange at the Scooter Avenue/Academy Drive intersection.

Project Need & Purpose

The purpose and need of this project are to increase east-west connectivity across the Seward Highway for vehicular and pedestrian traffic and to improve pedestrian safety in the project area. The proposed interchange will allow pedestrians to safely cross the Seward Highway instead of crossing it illegally and unsafely. It will also decrease congestion at neighboring interchanges at O’Malley Road and Dimond Boulevard, providing access between the eastern residential areas to the western commercial district.

Alternatives Analysis

• Alternative I: No-Build Alternative
  >Doesn’t meet the project goal.
• Alternative II: Roundabouts Above the Seward Highway
  >Large ROW impacts, steep grade for Scooter Avenue, Seward Highway elevation remains the same.
• Alternative III: Roundabouts Below the Seward Highway
  >Minimal ROW impacts, higher driver & pedestrian comfort.

Preferred Alternative-Alternative III

Single-lane roundabouts will connect Scooter Avenue and Academy Drive. The roundabouts will connect to Seward Highway via slip ramps and will feature crosswalks and a shared path for pedestrians and bicyclists. The Seward Highway will be elevated by 12 ft from existing to finished grade for adequate clearance between Seward Highway and the roundabouts (average profile grade is 2%), but its horizontal alignment will remain the same. The Scooter Avenue and Academy Drive vertical alignment will cut below existing ground (average profile grade is 2%) to ensure adequate clearance for the Seward Highway bridge. Its horizontal alignment requires ROW acquisitions from properties east of the Seward Highway.