How much would you pay to use the State Route 99 tunnel under Seattle?

The State Transportation Commission is commencing a new study on what drivers should pay to use the tunnel when it is completed. The problem: tolls can’t be so high that drivers will be discouraged from using the tunnel, but they must be high enough to provide $200 million in much-needed revenue to cover the project’s costs. If too many people avoid the tunnel while trying to dodge the toll, they’ll end up on I-5 or surface streets, making downtown Seattle’s near-gridlock even worse at peak hours.

The still-in-progress tunnel has overrun time and budget estimates, and the Washington State Department of Transit is hoping to recoup some of that investment–and provide for future transit projects–with a toll. The original proposed toll of $1 in the tunnel off-peak and $1.25 at peak hours was based on traffic data from 2006.  Seattle’s booming population and changing infrastructure have altered traffic patterns in the center of the city.

WSDOT is now studying a range of $1 to $1.50 for off-peak hours and $1.50 to $2.50 during peak commuting hours. That’s higher than original estimates, but lower than a previously considered variable rate that could rise as high as $3 at peak commuting hours.

Tolls won’t begin immediately when the tunnel opens; crews will take a few months to test tolling equipment in real-world conditions before taking the system live. While tolling may bring in some much-needed cash for a state in dire need of funding for infrastructure improvements, more details may need to be ironed out. Some estimates put the cost of collecting tolls at a third of the total revenue. And a recent audit found that Washington state is already failing to collect millions of dollars in tolls, and incorrect or obsolete data is resulting in thousands of bills being mailed late or to the wrong address.

Image: The partially completed southbound roadway deck inside the SR 99 tunnel. Image source: WSDOT