Toll-Paying Motorists Crowding-Out Carpoolers in Seattle Area Express Toll Lanes

A maximum toll was applied December 10 on Washington State's first Express Toll Lanes that opened September 27 outside of Seattle between King and Snohomish counties.

"The $10 designer toll lanes on Interstate 405 are fast becoming a symbol for Seattle rich," writes Seattle Times columnist Danny Westneat about the I-405 Express Toll Lanes Between Bellevue and Lynnwood. "But they also may be a sign of something that hasn’t gotten as much attention: the death of carpooling."

Ironically, before the Express Toll Lanes were created by converting the existing high-occupancy vehicle (HOV) lane to an express toll lane, and adding another such lane, the HOV line "was so well-used it started to become as congested as the regular lanes," writes Westneat.

According to data released by the state Department of Transportation, about 75 percent of weekday drivers in the express lanes in November didn’t have carpool status that allowed them to travel free.

What's more, what's happening in Washington may not be unusual.

In other cities that converted their HOV systems to high-occupancy toll (HOT) lanes, the carpoolers sometimes mysteriously vanished. In Atlanta there was an average loss of 2,500 carpools per day — about 20 percent of the total. Carpoolers stopped using the new HOT lane almost entirely — even though it was free to them. Many shifted to the general lanes. Nobody knows why.

Correspondent's note: While HOT lanes are a generic term for lanes that permit solo drivers to access carpool lanes for a toll, Washington has designated HOT lanes and express toll lanes, as explained here previously.

“Overall, we see a pattern of substantial decreases in carpools on many of the HOT lanes,” concluded researchers [PDF] at Texas A&M who looked at projects in eight cities, including the one in Atlanta.

Westneat goes on to describe findings of the Texas A&M study, the loss of carpooling in Los Angeles on the 110 High Occupancy Toll Lanes, and recognizes that carpooling has been in decline since 1980.

I was surprised to learn that one problem that The Evergreen State does not have in terms of oversubscription to its Express Toll Lanes are electric vehicles (EVs) that are permitted free access. And yet, "Washington leads the nation in recent per-capita sales of all electric passenger cars."