WSDOT’s longstanding TDM program getting much deserved recognition

By Bill Holloway

Since 1991, the Washington State DOT has been working with employers to reduce the number of people driving to work alone through the Commute Trip Reduction (CTR) program. A recent CityLab article, by Eric Jaffe, highlights the program’s impressive impact on driving habits and congestion. The CTR program affects only large employers—those with more than 100 employees—and requires them to implement programs to reduce the number of employees driving alone to work. Employers have used a wide range measures from transit pass programs and parking fees to mortgage discounts for employees who move closer to work.

The program has had a significant effect on the rate of solo commuting among employees at large companies in the state. While the percentage of people driving alone to work, both in Washington State and across the U.S., was relatively static from 2007 through 2010, the percentage of employees driving alone to CTR worksites during this period dropped by about 3%. This reduction in driving by workers at large Washington companies has markedly cut congestion on key routes as well. One analysis found that the program had reduced traffic delay on I-5 alone by about 320,000 vehicle-minutes per day, increased average speeds significantly, and decreased the spatial and temporal extent of daily congestion.

As more participating businesses realize the private benefits of participation, primarily in the form of reduced expenses for employee parking, WSDOT officials are hoping that a broader cultural shift will eventually eliminate the need for the CTR program. More details about the program and its successes can be found in the CityLab article.

Bill Holloway is a Transportation Policy Analyst at SSTI.