In 2019, Seattle Washington US released its Phase 1 study of congestion pricing in the city. The region's growth brought more traffic to existing roadways, increasing congestion, pollution, and reduced access to jobs.

This first phase of the Seattle Congestion Pricing Study addresses how to design a congestion pricing program for Seattle based on peer city experiences and lessons learned, as well as existing (albeit limited) data. The study screened potential pricing tools appropriate for Seattle residents, employees, visitors, and students of all backgrounds and incomes. Tools and programs were screened by four categories: equity, climate & health, traffic congestion, and implementation.

Equity was a key focus since lower income households spend a larger proportion of their budget on transportation (specifically if the household is dependent on car ownership).

Highlights from the report:

Pricing: (1) Successful pricing programs were built on aggressive transportation demand management programs; (2) Peer cities' congestion pricing programs aimed to reduce congestion and/or emissions; (3) Programs produced a revenue stream to fund transportation options and services; and (4) Initial public and business skepticism dropped (and acceptance rose) after the program launched and they could see how implementation works.

Equity and Affordability: (1) Include affordability and driver assistance for low income households who must drive; (2) Increase the availability and convenience of other modes such as transit, biking and new mobility; (3) Create special programs for seniors and people with disabilities; and (4) Accelerate clean vehicle programs 

Pricing Tools Evaluated: (1) Cordon Pricing; (2) Area Pricing; (3) Fleet or Vehicle Class Pricing; (4) Connected/Autonomous Vehicle Zone Pricing; (5) Fossil Free Zones; (6) License Plate Restriction Zones; (7) Road Usage Charges; (8) Arterial Toll Roads; (9) Arterial Express Lanes; (10) On-street Parking Pricing; and (11) Off-Street Parking Pricing.

Findings: Based on the results of the screening and the limitations of the existing data, Seattle only analyzed area pricing program (i.e. dharging people driving into or within downtown Seattle). From this assessment, the city's Census-based analysis suggests that approximately 13% of workers who drive in the region would be affected by a downtown pricing program.

Next Steps: The city will fill data gaps and analyze pricing proposal details (geography, methods, prices, discounts or exemptions, and other variables). While Phase 1 focused on equity, future analysis will also review effects on congestion, greenhouse gas emissions, mode shifts, costs and benefits, and time savings. In addition, the city will begin forming a public engagement program.

Seattle Congestion Pricing Study Phase 1 Summary Report: Seattle Department of Transportation 2019