I-405 HOT Lane Equity

Team Members

Project Lead: Mark Hallenbeck

Data Science Lead: Vaughn Iverson

DSSG Fellows: Shirley Leung, Cory McCartan, Kiana Roshan Zamir, and CJ Robinson

Abstract or executive summary

Congestion is increasing in cities around the country, and particularly in the Seattle region. Local governments are increasingly experimenting with congestion pricing schemes to manage congestion. The Washington State Department of Transportation (WSDOT) opened a congestion pricing facility in 2015 on I-405, which runs through the eastern suburbs of Seattle. The facility operates by selling extra space in the high-occupancy vehicle (HOV) lanes to single-occupancy vehicles (SOVs), and dynamically changing the price of entry to manage demand and keep the lanes operating. These combined HOV and tolled SOV lanes are called High Occupancy Tolling (HOT) lanes.

While the HOT lanes have been operative for over three years, there has been little research into the equity impacts of the lanes. Using data on each trip made on the I-405 HOT lanes in 2018, demographic data on census block groups, and lane speed, volume, and travel time data, we tried to answer this question. We studied how the express toll lanes are used, the benefits they provide to the region, and how these benefits are distributed among different groups of users.