Central Puget Sound State Route 520 - Dashboard
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Performance indicators for the SR 520 corridor in the central Puget Sound region.
Indicators
This dashboard shows three multimodal performance indicators for State Route 520 in the central Puget Sound region: annual general purpose lane person miles traveled, annual GP vehicle delay, percentage of park and ride spaces occupied.
For details on the methodology used to calculate person miles traveled and vehicle delay, see WSDOT's Handbook for Corridor Capacity Evaluation (PDF 5.9MB).
Sources: WSDOT Transportation Safety and Systems Analysis Division and WSDOT TRACFLOW (https://tracflow.wsdot.wa.gov/)
Note: Park & Rides utilization rates data will no longer available from 2020.
Multi-year trends
In 2021, annual GP person miles traveled and vehicle delay increased from 2020, due to the recovery of traffic volume. In 2020, the statewide response to the COVID-19 mitigation policy, such as an increase in telework and no large gatherings of events, resulted in reduced traffic. This significantly reduced the GP person miles traveled and vehicle delay compared to previous years. From 2015 through 2019, the central Puget Sound region experienced substantial economic growth, including increases in employment, which increased the number of commuters on the road. Annual GP person miles traveled on SR 520 decreased between 2015 and 2019, as did annual GP vehicle delay. Both of these decreases are likely the result of the HOV lanes on the new SR 520 floating bridge over Lake Washington, which opened in April 2016.
Traffic on this corridor is heavily influenced by congestion on the major north/south routes: I-5 and I-405. If these routes are congested, traffic backs up onto SR 520, resulting in delays. In 2020, as I-5 and I-405 experienced minor congestion, delay on SR 520 was far below previous years.
The SR 520 Evergreen Point Floating Bridge portion was tolled in both directions. Tolling on the SR 520 bridge was implemented to fund the new floating bridge, which opened with an HOV lane in each direction in spring 2016. For detailed information on the tolling of the SR 520 floating bridge, see SR 520 Bridge Tolling | WSDOT (wa.gov).
Annual highlights
In 2021, annual GP person miles traveled and vehicle delay increased from 2020, due to the recovery of traffic volume from earlier COVID-19 declines. Nearly 175 million person miles were traveled in the GP lanes on SR 520 between Seattle and Redmond, up 16% from 151 million in 2020. Travelers on this corridor experienced 4,000 hours of vehicle delay in 2020, compared to no delay in 2020.
In 2020, the statewide response to COVID-19 resulted in a significant reduction in GP person miles traveled and annual delay. Nearly 151 million person miles were traveled in the GP lanes on SR 520 between Seattle and Redmond, down 37% from 240 million in 2019. Travelers on this corridor experienced no vehicle delay in 2020, down 100% from 154,000 in 2019.
In 2019, about 240 million person miles were traveled in the GP lanes on SR 520 between Seattle and Redmond, down 2% from 244 million in 2018. Travelers on this corridor experienced 154,000 hours of vehicle delay in 2019, down 2% from 157,000 in 2018. Approximately 95% of available parking spaces at Park & Ride lots on this corridor were occupied in 2019, up from 82% in 2018.
In 2018, nearly 244 million person miles were traveled in the GP lanes on SR 520 between Seattle and Redmond, up 1% from 241 million in 2017. Travelers on this corridor experienced 157,000 hours of vehicle delay in 2018, up 11% from 142,000 in 2017. Approximately 82% of available parking spaces at Park & Ride lots on this corridor were occupied in 2018, down from 95% in 2017.
In 2017, over 241 million person miles were traveled in the GP lanes on SR 520 between Seattle and Redmond, down 3% from 249 million in 2016. Travelers on this corridor experienced 142,000 hours of vehicle delay in 2017, down 36% from 222,000 in 2016. Over 95% of parking spaces at Park & Ride lots on this corridor were occupied in 2017, up from 94% in 2016.
Highway capacity constraints vary based on the presence of managed lanes and multimodal travel options. Parts of the SR 520 corridor were served by high occupancy vehicle lanes in 2015 and 2017, although HOV lanes did not span the entire corridor and lane configurations changed between the two years. The westbound HOV lane at Medina on this corridor moved 42% more people in 2017 than each adjacent general purpose lane.