Central Puget Sound Interstate 405 - Dashboard


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Performance indicators for the I-405 corridor in the central Puget Sound region.

Indicators

This dashboard shows three multimodal performance indicators for Interstate 405 in the central Puget Sound region:

  1. Annual general purpose (GP) lane person miles traveled
  2. Annual GP vehicle delay
  3. Percentage of park and ride spaces occupied.



For details on the methodology used to calculate person miles traveled and vehicle delay, refer to 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 be available from 2020.

Multi-year trends

In 2022, annual GP person miles traveled and vehicle delay continued to increase compared to 2021, due to the ongoing recovery of traffic volume in the wake of COVID-19. However, person miles traveled and delay were still lower than the pre-pandemic levels.

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 2018 through 2019, the central Puget Sound region experienced substantial economic growth and increases in employment, which resulted in more commuters. During this time, rapidly increasing housing prices caused many Washingtonians in this region to move further from their workplaces to find affordable housing; many of these people commute on I-405. Annual GP person miles traveled decreased between 2018 and 2019, likely due to the addition of the Express Toll Lanes on I-405 between Bellevue and Lynnwood in the fall of 2015 and a northbound peak use shoulder lane in 2017.

Highway capacity constraints vary based on the presence of managed lanes and multimodal travel options; the I-405 corridor is served by transit buses, HOV lanes and, between Bellevue and Lynnwood, by Express Toll Lanes (ETLs). For detailed information about the I-405 ETLs, see WSDOT's I-405 Express Toll Lanes Between Bellevue and Lynnwood | WSDOT (wa.gov)

Annual highlights

In 2022, annual GP person miles traveled and vehicle delay increased due to the ongoing recovery of traffic volume in the wake of COVID-19. Annual GP person miles traveled in 2022 was 1.07 billion on I-405, between Tukwila and Lynnwood, up 1% from 1.06 billion in 2021. Travelers on this corridor experienced 1.6 million hours of vehicle delay in 2022, up 32% from 1.2 million hours in 2021.

In 2021, annual GP person miles traveled and vehicle delay increased from 2020, due to the recovery of traffic volume in the wake of COVID-19. Annual GP person miles traveled in 2021 was 1.1 billion on I-405, between Tukwila and Lynnwood, up 9% from 972 million in 2020. Travelers on this corridor experienced 1.2 million hours of vehicle delay in 2021, up 170% from 0.4 million hours in 2020.

In 2020, due to the statewide response to COVID-19 there was significant reduction in GP person miles traveled and annual delay compared to the previous year. Annual GP person miles traveled in 2020 was 972.3 million on I-405, between Tukwila and Lynnwood, down almost 13% from 1.1 billion in 2019. Travelers on this corridor experienced 446 thousand hours of vehicle delay in 2020, down 83% from 2019.

In 2019, about 1.1 billion person miles were traveled in the GP lanes on I-405 between Tukwila and Lynnwood, the same as in 2018. Travelers on this corridor experienced 2.7 million hours of vehicle delay in 2019, the same as in 2018. Approximately 98% of available parking spaces at Park & Ride lots along this corridor were occupied in 2019, up from 96% in 2018.

In 2018, over 1.1 billion person miles were traveled in the GP lanes on I-405 between Tukwila and Lynnwood, the same as in 2017. Travelers on this corridor experienced 2.7 million hours of vehicle delay in 2018, up 8% from 2.5 million in 2017. Approximately 96% of parking spaces at Park & Ride lots along this corridor were occupied in 2018, down from 98% in 2017.

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