Vancouver region Interstate 5 - Throughput
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Measures of throughput productivity on the I-5 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
In 2022 similar to 2021, throughput productivity improved.
In 2020, due to COVID-19 initiatives, the afternoon loss of productivity was not as long, lasting 10-20 minutes. Southbound throughput productivity at the same location saw a dramatic change, occurring during approximately the same part of the morning commute and going from as low as 65% in 2018 to 100% in 2022.
Throughput productivity worsened from 2018 to 2019.
Annual highlights
In 2022, throughput productivity was similar to 2021.
In 2022, vehicle throughput at I-5 near Fourth Plain Boulevard (MP 1.4) was around 85% of maximum throughput at their most congested times in both northbound and southbound.
In 2021, throughput productivity improved in both northbound and southbound direction compared to 2020.
In 2021, vehicle throughput at I-5 near Fourth Plain Boulevard (MP 1.4) ranged from 83% to 87% of maximum throughput at their most congested times.
In 2020, due to the statewide response to COVID-19, there was a significant reduction in volumes and resultant declines in lost productivity.
In 2020, vehicle throughput at I-5 near Fourth Plain Boulevard (MP 1.4) ranged from 55% to 68% of maximum throughput at their most congested times. Throughput productivity varies by direction of travel, location and time of day. For example, northbound throughput productivity at this location in 2020 was 65% at 5:25 p.m.
In 2019, vehicle throughput at I-5 near Fourth Plain Boulevard (MP 1.4) ranged from 53% to 70% of maximum throughput at their most congested times. Throughput productivity varies by direction of travel, location and time of day. For example, northbound throughput productivity at this location in 2019 was at 67% at 2:20 p.m.
In 2018, vehicle throughput at I-5 near Fourth Plain Boulevard (MP 1.4) ranged from 65% to 89% of maximum throughput at their most congested times. Throughput productivity varies by direction of travel, location and time of day. For example, southbound, throughput productivity at this location in 2018 was at 66% at 6:30 a.m.