Housing Affordability And Traffic Collide

Growing population plus limited housing supply near job centers have helped jack prices sky high in the Seattle region, and add to ex-urban growth. Usage of express toll lanes in the key I-405 corridor has grown, and some lawmakers say more capacity is needed. Currently the I-405 toll lanes continue to perform well, but have slipped slightly on one measure in the latest report. Photo of I-405: Henry Alva.

Despite often fierce reactions to express toll lanes installed in 2015 on I-405’s northern portion, recent state data show most toll lane and general-purpose lane drivers on the highway get where they’re going more quickly, compared to before tolling. That’s according to the latest performance update by the Washington State Department of Transportation (WSDOT), covering April through September.

However, the report also found that overall, the I-405 toll lanes are meeting minimum standards for smooth traffic flow slightly less than in the last report. That appears to be a function of growing usage, and a choke point where two toll lanes in each direction narrow to one.

Influx Of Residents, Workers Continues

Population and housing pressures are central to regional traffic congestion challenges that have sounded an alarm for major employers.

Since 2000, Puget Sound regional population has jumped from three million to nearly four million. The Puget Sound Regional Council anticipates another million new residents in its four-county domain by 2040. Between 2010 and 2014, King County alone added 115,000 jobs, Snohomish County 28,000, and Pierce County 15,000.

The employment growth has boosted demand for affordable housing, but a limited supply is available. That is due not only to the influx of workers, but also to restrictions under the state’s Growth Management Act. Jobs growth and record tight housing supply have driven prices higher.

Priced Out Of King County

According to the Northwest Multiple Listing Service, the November median closing sales price of a single family home in King County was $550,000. For Snohomish and Pierce counties, the figures were $399,000 and $287,000, respectively.

The housing price disparity becomes more apparent city by city. According to Zillow, the estimated average market value of a Marysville single family home in Snohomish County is currently $302,800 – almost half that of a Kirkland home, in King County, at $595,300. The neighboring King County cities of Bellevue and Redmond run higher still, at $743,500 and $703,200 respectively, according to Zillow.

Even in relatively cheap King County communities such as Black Diamond and Kent, average market values for single-family homes top $330,000, according to Zillow. In once-modest Renton, it’s $400,000-plus.

Reaping The Consequences Of ‘Drive to Buy’

All this has fueled what realtors call the “drive to buy” tendency, where purchasers seek more affordable homes that are ever farther from job centers in the I-405, I-90 and I-5 corridors. More traffic results.

Allison Butcher is senior policy analyst for the Master Builders Association for King and Snohomish Counties. She told Lens an inadequate housing supply, caused in part by a lack of available land, and stringent land use regulations, is driving up home prices. She added this is “creating increased traffic as a side effect,” as employees working in King County move north or south where housing is more affordable.

WSDOT Assistant Secretary Patty Rubstello made a similar observation during a December 1 presentation to the House Transportation Committee. She told committee members “a lot more traffic is out there, not only on 405 but on the local streets as well,” due to growth in north King County and south Snohomish County.

More Traffic In I-405 Toll Lanes

Between October of 2015 and September of 2016, southbound I-405 express toll lanes at State Route 522 and State Route 527 had 30 percent more peak-hour traffic than a year before. For the northbound express toll lanes in those segments, there were increases in peak-hour vehicle volume of 11 percent and 34 percent, respectively.

The WSDOT report found that the new toll lanes added to I-405 in 2015 met the legislature’s minimum performance standard of 45 miles per hour on average, 85 percent of the time from April through September of this year.

Although that’s considerably higher than the 60 percent the highway’s carpool lanes had achieved prior to tolls, it is a drop from the previous six-month report on I-405 toll lanes, when the 45 mph requirement was met 91 percent of the time.

At the December 1 meeting, Rubstello told lawmakers the change results from a bottleneck in the northern part of the corridor between Bothell and Lynwood, where the dual HOV lanes in both directions are reduced to only one. In contrast, the dual toll lane sections of I-405 both southbound and northbound did hit the 90 percent threshold for April through September.

South of Bellevue on I-405, as it winds toward Renton and the highway’s southern endpoint at I-5, there are not yet any express toll lanes, and massive backups on weeknights are common.

By September 2017, lawmakers have stipulated the I-405 tolling system must be financially self-sustaining, or the tolled lanes must meet the 45 mph standard 90 percent of the time. Otherwise, I-405 tolling will be discontinued. System revenues continue to exceed costs.

Travel times in the I-405 general purpose lanes remain better than before tolling, according to Rubstello. One exception continues to be northbound I-405 between SR 522 and I-5, where five lanes total shrink to three. WSDOT officials hope a planned shoulder lane from SR 527 to I-5, scheduled to open next spring, will help.

More Capacity Needed

Although the added shoulder lane will be a “welcome Band-Aid, it is still a Band-Aid” that won’t fix the long-term problems north I-405 faces, said State Senator-elect Guy Palumbo (D-1). He told Lens that more road capacity is needed to keep up with vehicle volumes, but he doubts toll revenue will be sufficient to cover the costs of extending the dual toll lanes all the way north to I-5.

One way to fund such improvements might be via federal grants, or possibly bonding against future growth in project areas, Palumbo said.

Rep. Mark Hargrove (R-47) is the assistant ranking minority member for the House Transportation Committee. He told Lens that the region’s transportation infrastructure suffers from inconsistencies in capacity. “Seattle’s one of the few areas where you can go into a big city and…have less lanes,” he said.

Hargorve added, “If you’re getting more growth and congestion on the north end (of I-405) and you get less lanes,” that doesn’t make sense.

The imbalance between regional growth and adequate transportation infrastructure is “unsustainable” in the long run, said Palumbo. He added, “We are at the breaking point.”


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