Sound Transit is improving access to Puyallup and Sumner Stations for riders, whether they arrive by walking, bicycling, transit or driving. Parametrix led the alternatives analysis/planning, preliminary design, NEPA/SEPA clearance, and design-build procurement documents for Sound Transit’s multi-modal access improvements at these two stations. During the planning and alternatives analysis, we conducted an extensive public and agency involvement program to develop, evaluate, and refine potential alternatives covering multimodal improvements including intersection, interchange, pedestrian/bicycle, parking and bus/paratransit transit access improvements.

We conducted substantial traffic analysis for both cities including Synchro and VISSIM simulations. Sumner and Puyallup both had separate environmental documentation packages, designed to meet FTA’s latest streamlined CE category requirements combined with a SEPA checklist, with more detailed supporting documentation on selected topics such as traffic, noise, and cultural resources. Parametrix helped Sound Transit prepare design-build RFPs for these projects, plus a template for design-build project requirements for future ST parking garages.

The Puyallup improvements, including a new 510-space garage, 163-space new surface parking, new traffic signals, and additional lanes and bicycle lanes have been completed. Sound Transit selected a design-build team for the Sumner improvements final design and construction and expects to have those completed in 2026.