Traffic Payout

By Jennifer Rash

Big changes are coming for I-405 drivers later this year. We’re building express toll lanes on southbound and northbound I-405 between Bellevue and Lynnwood to help ease traffic on one of the state’s most congested corridors. One of the biggest changes coming this fall is a proposed change in the HOV requirements from two or more people to three or more people during peak commute hours, part of the toll rate and exemption proposal by the Washington State Transportation Commission.

We’ve heard a variety of reactions from folks about this proposal, and decided to tackle some of them in a two-part blog series. In this first post, we will discuss the problem we’re facing through a series of common questions we’ve received. In the second part, we’ll talk about how express toll lanes are part of the solution for I-405.

The ABC’s of HOV Lanes
To get to the solution, we have to start at the beginning. Return with me, won’t you, to November 1992. Aladdin opened at the box office, in Nashville, the great Miley Cyrus was born, and in Olympia, WSDOT adopted its Statewide Freeway HOV Policy. It was a magical time.

The main goal of HOV lanes was (and still is) to maximize the movement of people rather than vehicles, whether that’s in a carpool, vanpool or bus.  The target is to keep traffic moving consistently at a minimum speed of 45 mph to provide a reliable trip.  By reducing the number of single-occupant vehicles on the roadway, HOV lanes also help improve traffic in the regular lanes.  For example, when 15 people opt to get out of their cars to ride the bus or carpool with a co-worker, it removes up to 15 cars from the general purpose lanes.

Animation illustrating how HOV lanes work.

In 1994, the HOV Monitoring and Evaluation Technical Report showed that the majority of respondents in a public opinion survey supported HOV lanes and overwhelming supported that all HOV lanes should be open to vehicles with two or more people.

What’s happening with HOV lanes on I-405 now?

Congested HOV lane on I-405.

Fast-forward 23 years. If you drive I-405, you’ve likely experienced that the HOV lanes are often as congested as the regular lanes during peak periods. That’s because there is too much demand for the lanes. Last year, WSDOT completed the I-405/SR 167 Funding and Phasing Report which found that the existing carpool lane north of SR 522, the one lane section of the future express toll lanes project, is at capacity during peak periods. It also found that there are 200 or more days a year when speeds are below 45 mph in the HOV lane on southbound I-405, south of SR 527.

What is causing the increased demand?
There’s a clear connection between the break down in the I-405 HOV lanes and population growth on the eastside.  U.S. Census data shows that over the last 10 years, Seattle’s population grew seven percent, while the population on the Eastside, from roughly the Snohomish County line to Newcastle and everything east of Lake Washington to the crest of the Cascades, increased 15 percent.
Washington’s residential and employment populations are only projected to increase.  In the years ahead, the population of the city of Portland will be added to our region. We have a tremendous challenge to accommodate this massive growth.

Shouldn’t growth mean building more regular lanes?
That’s a common perception, but over the long term, it’s been shown time and time again that new lanes eventually become congested and simply add to the problem. We also must keep in mind that continually adding lanes our highways could also have impacts to local streets. We know from experience here and across the nation that we cannot simply build our way out of congestion, and we know that we need to get creative to manage the growing demand on our roadways. One of the best ways to do that is to learn from what’s working in other states facing similar challenges.

What is WSDOT doing to create solutions for increasing demand on I-405?
Over the last decade, WSDOT has worked with cities, counties, federal agencies, transit agencies and community groups to develop consensus on a long-term vision for the multimodal redevelopment of this highway. We adopted a multi-modal approach to ease congestion on I-405 that included, adding more lanes, improvements to local roads, increasing transit service, adding park and ride spaces and vanpools, and the possibility for an express toll lane system. 

After three published studies on I-405 express toll lanes, one of which was review by a panel of nation experts, WSDOT is implementing express toll lanes on I-405. Express toll lanes are a proven strategy for congestion relief that have been implemented, studied and expanded across the country.

In the next post, we’ll discuss how express toll lanes will work in Washington as part of the solution for I-405.