What will traffic do when SR 520 tolling starts?

By guest blogger Emily Pace

The big question when SR 520 tolling starts Thursday, Dec. 29, is if drivers will continue to use the bridge, travel at off-peak times to pay a cheaper toll rate, find an alternate route, take the bus or just stay home.

We’ve tried to come up with an answer by surveying bridge users and creating traffic forecasts. We’ve collected a lot of data about what people might do once tolling starts, but ultimately, it’s hard to predict what drivers will do.

What can drivers do? Plan ahead and allow extra time.

Without a doubt, it will take a while for drivers to settle into a new pattern after tolling starts – up to six months. Don’t expect traffic to behave the same way every day. While there are other routes around Lake Washington like I-90, SR 522 and I-405-to-I-5, these may be even more congested as traffic reroutes to avoid tolls.

Drivers have several choices when tolling starts:

  • Get a Good To Go! pass and save $1.50 each way in tolls when crossing the SR 520 bridge.
  • Travel during off-peak periods to pay cheaper toll rates: Get familiar with the SR 520 toll rates online or download the WSDOT mobile App.
  • Ride the bus: Take advantage of the 730 daily bus trips across SR 520. King County Metro and Sound Transit expanded service earlier this year in preparation for tolling.
  • Share the ride: Visit RideshareOnline.com to join a vanpool or carpool. Drivers are also encouraged to work with their employers to look into compressing or changing work hours and teleworking.

Plan ahead, allow extra time and pack your patience as traffic on all major roadways will be very different after SR 520 tolling starts. You can always get up-to-date traffic information on our website before you leave.

What are we doing to help drivers?

We will closely monitor all of the routes around and across Lake Washington to determine how tolling affects traffic. We will track travel times, ensure signal coordination, and collect traffic volumes on highways and local roads.  We’ll also be using our traffic tools like travel time signs, ramp meters and electronic message signs. We’ll even have extra Incident Response Team patrols out on the road to help clear incidents and keep traffic moving.

We’re working with local governments around the lake to share data because we know it’s not just about highways but also local streets. We will share what we learn about the effect of tolling on traffic with the public, local governments, the Legislature and the Transportation Commission.

What will be the new “normal” after traffic adjusts?

It will take time for drivers to adjust to a new “normal” after tolling starts. When people settle into new routines after six months or so, we anticipate more traffic will return to SR 520 as drivers find paying a toll for a more reliable trip across the bridge is worth it.

After several months we expect to see the following changes in travel speeds during peak periods:

  • Westbound SR 520 morning commute: 20 mph faster
  • Westbound I-90 morning commute: 5 to 10 mph slower
  • Westbound SR 522 morning commute: 5 mph slower

Are we going to toll I-90?

Not at this time. Legislative authorization is required to toll any new corridors, including I-90, and tolling I-90 would also have to be coordinated with the Federal Highway Administration (FHWA). Even with approval from legislature and FHWA, starting tolling on I-90 would be years away. Time intensive work such as developing environmental studies, designing the toll system and starting the contract bid process would still need to be completed.