I-405 Tolls Fund More Highway Capacity

I-405 near Canyon Park. Photo by SounderBruce

While they remain controversial politically, the HOT lanes on I-405 between Bellevue and Lynnwood are increasingly popular with transit users and the drivers who use the lanes. Higher than forecast driver demand has led to higher toll revenues, and those revenues are being put to work to benefit drivers in the corridor. The first improvement is a 1.8 mile shoulder lane for general purpose traffic between Canyon Park and I-5. The improvements may also benefit transit users.

Shoulder lanes will be added in 2017 between SR 527 and I-5. Map: WSDOT

As demand has grown, average peak time toll rates have crept up from $1.75 in late 2015, to $2.40 in the first quarter, to $2.72 in the second. In June, the HOT lanes served 1.2 million vehicle trips, over 800,000 of those tolled. With higher prices and HOT lane volumes, WSDOT now anticipates revenues will exceed earlier forecasts by about $20 million per biennium.

The lanes have worked well for transit too, with Metro seeing 8.2% more riders. Average travel savings are 2.1 minutes in the AM and 5.8 minutes in the PM. Community Transit's peak ridership is up 3% with improved travel times for most routes.

Initially, express lanes were tolled at all hours. In a concession to tolling opponents in the Legislature, that was pared back earlier this year so tolls now apply only between 5am and 7pm weekdays. The lanes are open to all drivers at other times, although center HOV ramps in Bellevue and Totem Lake are HOV/transit only when tolled access is not available.

Travel times for drivers in the general purpose lanes are generally better than before, particularly southbound. In the northbound direction, traffic flows more freely through Bellevue and Kirkland. But this has exacerbated a bottleneck at SR 522 in Bothell, where five lanes (2 HOT + 3 GP) converge into three (1 HOT + 2 GP). The highway remains congested until near I-5. Nearly 1,000 vehicles an hour merge onto I-405 at Canyon Park in the PM peak, adding to delays.

WSDOT hopes to ease that bottleneck by adding shoulder-running on the northbound side of I-405 between SR 527 and I-5. Unlike the short bus-only shoulder lanes on SB I-405, the northbound shoulder will be available to all vehicles. The added shoulder lane would start where the merge lane from the SR 527 on-ramp ends, and extend to the exit lanes near I-5. The shoulder lane will be opened when speeds in the two GP lanes slow. Access to the lanes will be signal-controlled. Effectively, it is a third general purpose lane at high volume times.

Signs will alert drivers when they are allowed to use the shoulder lane. Photo: WSDOT

ST Express and other buses already run on the shoulder in several places on SB I-405 in the Bothell area, and this has improved performance for those buses. As an "early deliverable" for ST3, Sound Transit pledged to look at shoulder-running for buses elsewhere. WSDOT will allow buses to use these shoulder lanes along with other vehicles. However, the WSDOT plan eliminates the opportunity for exclusive transit use of the northbound shoulders.

Sound Transit and WSDOT expect increased general purpose lane capacity will be better for buses than the status quo. Because I-405 lacks center ramps in this area, there are no plans for Sound Transit buses to move to the HOT lane. Even the I-405 BRT will not use HOT lanes north of Brickyard P&R. Anything that speeds GP lane traffic is anticipated to improve transit performance too. WSDOT staff believe that relieving the bottleneck north of Canyon Park may even ease traffic back to SR 522.

WSDOT hopes to open the shoulder lanes to traffic by Summer 2017. In the longer run, bus and GP performance in the corridor will be improved by adding a second HOT lane at the north end of I-405. That project is estimated at $570 million and, despite some more recent political interest, is not funded.

I-405 BRT investments are described in this recent slide presented to the I-405/SR 167 Executive Advisory Group.