Vancouver region Interstate 205 - Throughput
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Measures of throughput productivity on the I-205 corridor in the Vancouver area
Throughput productivity
Throughput productivity measures how efficiently existing highway capacity is being used. It can be reported for vehicles or travelers, making it a very adaptive metric. WSDOT uses the maximum throughput standard to assess travel delay relative to a highway's most efficient speed, which is 85% of the posted speed limit.
Lost throughput productivity is the percentage change of highway throughput in respect to maximum throughput due to congestion and other events that cause vehicles to travel below a threshold speed. See WSDOT's how to calculate throughput productivity (PDF 5.9MB).
In order to gauge the lost productivity on I-5, I-205, and SR 14 in the Vancouver region, WSDOT analyzed vehicle throughput at three locations: I-5 near Fourth Plain Boulevard (MP 1.4), I-205 near 10th Street (MP 28.0), and SR 14 near Lieser Road (MP 4.5).
Sources: WSDOT Transportation Safety and Systems Analysis Division and WSDOT TRACFLOW (https://tracflow.wsdot.wa.gov/)
Note: Source data collection devices were updated in 2017.
Multi-year trends
Throughput productivity did not change significantly between 2022 and 2021.
In 2020, due to the statewide response to COVID-19, there was no loss of vehicle throughput.
Northbound I-205 at 10th Street saw no loss of throughput productivity in 2018 and 2019, while lost throughput productivity on I-205 southbound during the morning commute at this location increased from 2018 to 2019.
Annual highlights
In 2022, there were no significant changes in throughput productivity compared to 2021. Southbound vehicle throughput at I-205 near 10th Street (MP 28.0) did not experience any lost productivity in 2022, a slight improvement compared to 2021.
In 2021, there were no significant changes in throughput productivity compared to 2020.
In 2020, due to the statewide response to COVID-19 there was no significant drop in vehicle throughput. Southbound vehicle throughput at I-205 near 10th Street (MP 28.0) decreased to 61% of maximum throughput at 6:40 a.m. but quickly recovered.
In 2019, vehicle throughput at I-205 near 10th Street (MP 28.0) ranged from 52% to 80% of maximum at its most congested times. Throughput productivity varies by direction of travel, location and time of day. For example, in 2018 and 2019 at 8:20 am., about 40% of the freeway's southbound capacity was reduced due to slower speeds caused by congestion near 10th Street. Throughput productivity loss lasted 30 minutes longer in 2019 than in 2018, starting at 6:00 a.m. and ending at 8:55 a.m.
In 2018, vehicle throughput at I-205 near 10th Street (MP 28.0) ranged from 61% to 80% of maximum throughput at its most congested times. Throughput productivity varies by direction of travel, location and time of day. For example, in 2018, 39% of the freeway's capacity was reduced due to slower speeds caused by congestion for commuters traveling southbound near 10th Street at 8:20 a.m. Throughput productivity loss was 30 minutes shorter in 2018 than it was in 2017, starting at 6:05 a.m. and ending at 8:25 a.m.