Study: High Occupancy Toll Lanes Slow Traffic in Adjacent Free Lanes

HOT lanes are supposed to not only speed traffic flow for paying solo motorists in the carpool lane, but improve traffic flow in the adjacent free lanes, according to theory. A new study on express toll lanes in Seattle disproved that last part.

2 minute read

February 15, 2016, 7:00 AM PST

By Irvin Dawid


Carpool Lane

Rhonda Roth / Shutterstock

"An early report has found that traffic on Interstate 405 has gotten slower and more congested since tolling began last September on the Bellevue to Lynnwood section of the [Seattle area] freeway," writes Daniel DeMay for Seattle PI.

The independent assessment, conducted by Kirkland-based INRIX, found that HOV lanes saw higher speeds after tolls began, but "speeds in the general-purpose lanes have generally gotten worse for the majority of drivers."

INRIX publishes an Urban Mobility Scorecard Annual Report so they know what they are doing when it comes to measuring congestion. However, the results are refuted by WSDOT and the Washington State Transportation Center (TRAC). "Both say the report uses too small a data sample to paint an accurate picture of the full impact of tolling," writes DeMay.

INRIX breaks down their congestion report into sections of the toll lanes which max-out at $10. WSDOT claims that INRIX doesn't account for the capacity of the roadway in its results. See the review [PDF] from Mark E. Hallenbeck, Director, Washington State Transportation Center.

"My frustration with INRIX, who has the data to do a better job, is it's a really unfair characterization of what's going on," he said. "And that unbalanced view of what's going on, when simply picked up and run with, results in really bad transportation policy decisions."

Revenue Exceeding Projection

As indicated in a December post, the express toll lanes are very popular with motorists. WSDOT reported "that it collected $3.7 million in revenue from Sept. 27, 2015, when tolling began, through the end of the year; the state had projected just $1 million," adds DeMay.

Tollway Rebellion?

"At least some drivers have been in an uproar over the tolling, with more than 30,000 signing a petition to end the tolling, and state Sen. Andy Hill, R-Redmond, pushing a bill that would make the lanes free between 7 p.m. and 5 a.m. and on weekends and holidays," writes DeMay.

Ugly Politics

Hill and other Senate Republicans last Friday fired the state's transportation secretary, Lynn Peterson, possibly over I-405 tolling and its rough rollout, though its still unclear if it was one of the state's problematic transportation projects or the combination of troubles that triggered a vote to against confirming her appointment.

She was appointed by Gov. Jay Inslee (D) to the position three years ago.

Hat tip to AASHTO Daily Journal

Thursday, February 11, 2016 in Seattle PI

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