Study evaluates urban traffic congestion. Spoiler: Metro Seattle commute is among the worst.

Seattle metro commuters lose 138 hours annually to congestion, ranking it among the most congested cities in the nation. That’s according to the INRIX 2018 Global Traffic Scorecard.  The metro Puget Sound commute ranks up there with Boston, the District of Columbia and Chicago.

Boston and Washington D.C. are the top two cities in the U.S. both in terms of impact and time wasted. Drivers in each city lose up to 164 and 155 hours in traffic, respectively. Their geography, age and density create a road network that enters a severe state of breakdown once traffic strikes. In each, drivers experience congestion more than 15 hours per year greater than the next worst cities in terms of total hours: Chicago (138) and Seattle (138).

The firm slices the data several ways. Here’s a good summary table from the report, which shows Seattle tied at 6th for total impact, unchanged from a year ago..

The rankings are defined this way.

  • Impact Rank: Impact rank is a calculated commute based upon a city’s population and the delay attributable to congestion.

  • Urban Area: The geographic scope of a city as defined by its road network density.

  • Hours Lost in Congestion: The total number of hours lost in congestion during peak commute periods compared to free-flow conditions.

  • Year-Over-Year Change: The percentage difference in hours lost in congestion in 2018 compared to 2017.

  • Last Mile Travel Time: The time it takes to travel one mile into the central business district during peak hours.

  • Last Mile Speed: The speed at which a driver can expect to travel one mile into the central business district during peak hours.

The Seattle Times reports on the study, pointing out infrastructure investments are being directed toward easing the problems.

Washington state is still ramping up the Connecting Washington program funded by 2015-16 increases in the gas tax. Projects include a bigger Highway 520 in Seattle; an I-405 widening to add mostly toll lanes in Renton; a widening of Highway 167 sections near Auburn; more I-5 lanes at Joint Base Lewis-McChord; and the North Spokane Corridor that creates a long-awaited freight bypass but promotes sprawl.

In its report on the study, Geek Wire adds that there’s likely to be a tough patch ahead.

Seattle traffic isn’t likely to improve in the near future. Demolition of the Alaskan Way Viaduct and the opening of the new SR 99 Tunnel this month kicked off the “period of maximum constraint” in which construction projects and a growing population are expected to put a greater squeeze on Seattle’s transportation infrastructure.

There are more than 60 construction cranes dotting the city’s horizon and the Seattle Department of Transportation says “work is expected to intensify over the coming months.” Megaprojects like the expansion of the Washington State Convention Center are expected to increase congestion.

INRIX reports on the upside of congestions, though frustrated commuters may find little solace in the finding.

While congestion incurs costs from time loss, increased pollution rates, and higher incidents of accidents, its presence is indicative of positive economic trends and a city’s desirability. The occurrence of many of the world’s most dynamic cities in this report should serve as no surprise. Higher density and population correlate directly with economic growth and innovation rates, while their co-occurrence has a multiplier effect. The larger and denser the city is the more significant the benefits accrued to an individual city. Agglomeration economics is the phenomena of increasing productivity as a function of size and density. For example, the Top 5 largest metros in the U.S. by GDP accounted for 26 percent of the nation’s GDP, in 2017, but represented only 17 percent of the nation’s population. While congestion itself has little intrinsic worth, it’s symptomatic of economic vitality. [Footnotes deleted.]

We’ve written recently about the importance of infrastructure investment (here and here). The Connecting Washington investments have been and continue to be a part of responding to the congestion resulting from the metro area’s economic prosperity. It’s also clear that more will be required to sustain and nurture future growth.