Spokane region Interstate 90 - Delay
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Measures of delay on I-90 in the Spokane region
Travel delay
Travel delay is the amount of extra time spent at speeds below a given threshold—such as the posted speed limit or the maximum throughput speed on a highway. WSDOT uses maximum throughput speed (85% of posted speed limit) as its threshold for calculating delay, which it measures in either annual hours of delay per vehicle or annual hours of delay per person. For details on methodology to calculate travel delay, refer to WSDOT's Handbook for Corridor Capacity Evaluation (PDF 5.9MB).
Heat maps
The heat maps below show vehicle hours of delay by time of day (measured in 5-minute intervals) and milepost. The darker the shading in a particular spot on the heat map, the more hours of delay occurred at that time and place. Shading is standardized across all the corridors to allow for comparison.
There is a separate heat map for each direction of travel. The eastbound graph below reads from left to right, while the westbound graph reads from right to left. For additional details on how to read heat maps, refer to the 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
Delay in 2023 increased compared to 2022, but was still lower than pre-pandemic levels. Eastbound delay on I-90 in the Spokane region increased slightly compared to 2022 during the evening commutes. Westbound delay in 2023 saw significant increases at Custer Street.
In 2022 delay increased compared to 2021, but still lower compared to pre-pandemic levels. Eastbound delay on I-90 in the Spokane region increased significantly compared to 2021 during the morning and evening commutes. Westbound delay in 2022 also saw slight increases in commute times.
In 2021 delay increased compared to 2020, but still lower compared to pre-pandemic levels. Eastbound delay on I-90 in the Spokane region increased significantly compared to 2020 during the morning and evening commutes. Westbound delay in 2021 also saw slight increases in commute times.
In 2020, due to the statewide response to COVID-19 there was significant decrease in delay compared to previous year. Eastbound delay on I-90 in the Spokane region decreased significantly compared to 2019 during the morning and evening commutes. Westbound delay in 2020 also saw significant decreases commute times.
In 2019, eastbound vehicle delay on I-90 in the Spokane region increased slightly compared to 2018, occurring during both the morning and evening commutes near the approach to the SR 290 interchange. Westbound delay in 2019 also saw slight increases from 2018 between Francher Road and Freya Street in the morning between 7-9 a.m. and in the evening between 4-6 p.m.