Central Puget Sound Interstate 405 - Severe congestion
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Measures of severe congestion on I-405 in the central Puget Sound region
Severe congestion
Severe congestion occurs when highway travel speeds are slower than 60% of the posted speed (about 36 mph for a 60 mph speed limit) leading to reduced highway efficiency. 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/)
Performance highlights
Commuters driving from Everett to Bellevue on I-405 experienced severe congestion with speeds of 36 mph or less:
- At 7:30 a.m. on 69.6% of weekdays in 2023 up from 63.3% in 2022.
Likewise, travelers experienced severe congestion between Bellevue to Everett:
- At 4:25 p.m. on 60.6% of weekdays in 2023 compared to 35.0% in 2022.
In 2022, severe congestion increased compared to 2021, due to the ongoing recovery of travel volume in the wake of COVID-19. Commuters driving from Everett to Bellevue on I-405 in 2022 drove in severely congested conditions in the morning (speeds of 36 mph or less) more often than in 2021. For example, at 7:30 a.m. speeds on this commute were below 36 mph on 63.3% of weekdays in 2022—up from 43.3% of weekdays in 2021.
In 2021, severe congestion increased compared to 2020, due to the recovery of travel volume in the wake of COVID-19. Commuters driving from Everett to Bellevue on I-405 in 2021 drove in severely congested conditions in the morning (speeds of 36 mph or less) more often than in 2020. For example, at 7:30 a.m. speeds on this commute were below 36 mph on 43.3% of weekdays in 2021—up from 16.9% of weekdays in 2020.
In 2020, due to the statewide response to COVID-19 there was significant decrease in severe congestion compared to 2019. Commuters in 2020 driving from Everett to Bellevue on I-405 drove in severely congested conditions in the morning time (speeds of 36 mph or less) less often than in 2019. For example, at 8 a.m. speeds on this commute were below 36 mph on 15.8% of weekdays in 2020—down from 84.6% of weekdays in 2019.
In 2019, commuters driving from Everett to Bellevue on I-405 drove in severely congested conditions in the morning time (speeds of 36 mph or less) more often than in 2018. For example, at 8 a.m. speeds on this commute were below 36 mph on 84.6% of weekdays in 2019—up from 79% of weekdays in 2018.