The southernmost bridge in the City of Portland, the Sellwood Bridge, carries over 25,000 vehicles per day on a crumbling two-lane bridge with one three-foot sidewalk. Alta Planning + Design helped determine the future configuration of the new Sellwood Bridge for between 9,000 and 16,000 pedestrian and bicycle users each day.
In the first phase, Alta developed and evaluated cross section alternatives, interchange design, access, and alignment issues. Alta also developed a long-range forecast/estimate of bicycle/pedestrian demand, based on a combination of several forecasting methods. Alta was involved in the public engagement process and facilitated a series of ped/bicycle-focused workshops.
Alta assisted with the design of the bridge’s bicycle and pedestrian elements, including non-motorized components of the bridge structure (e.g., facility types and widths, signing and striping treatments), and bicycle/pedestrian accommodations through a series of complex interchange areas. Key design elements included establishing safe, intuitive and streamlined connections to nearby bus stops, a future streetcar line, and two of Portland’s most popular trail corridors. The design also includes features to minimize conflicts among a variety of anticipated users ranging from commuter cyclists to families walking with children. Alta also developed bicycle/pedestrian temporary traffic control plans to accommodate non-motorized users during the four-year construction period, including elements to safely guide users through the work zone, and detour routes during bridge closures.
Additional Alta tasks included facilitation of Bicycle/Pedestrian Technical Working Group meetings, and assistance with community outreach efforts.