After six months, the Washington State Department of Transportation claims the Express Toll Lanes on Interstate 405 are working better than anticipated.

Mostly.

In the two “peak” periods of an average workday (that is, heading southbound on I-405 between Lynnwood and Bellevue in the morning and northbound in the evening) the average commute has improved by several minutes in three of four measured areas.

In the fourth, between state routes 522 and 527, the average northbound commute has actually slowed by three minutes.

Even so, according to data provided by the department, more than 90 percent of drivers using the express toll lanes are seeing speeds of 45 mph or faster. In 2015, before the lanes were opened, southbound drivers only went 45 mph or faster 78 percent of the time. For northbound traffic, it’s improved to 92 percent from an abysmal 44 percent.

Kate Elliott, author of the report put out by the department, acknowledged that the lanes aren’t perfect, but the department was working to fix that.

“While the numbers are encouraging, we know that some drivers have been impacted negatively. There are drivers whose trips, especially between SR 522 and SR 527, have seen slower speeds since express toll lanes opened,” she wrote. “We are working to expedite several adjustments, especially those to the northern section of the corridor, so that travelers will see improvement as soon as possible. This includes adding capacity through hard shoulder running.”

Since the express toll lanes opened on Sept. 27, 2015, more than 7.5 million total trips (5.1 million of which were tolled) have been taken in the express lanes in more than 782,000 different vehicles — the equivalent of a tenth of all vehicles in the state of Washington.

Additional numbers from the first six months show that 34,000 vehicles every day pay the toll, and 84 percent of those drivers pay $4 or less per trip. Southbound drivers in the lanes save an average of 10 minutes and northbound drivers save an average of 13 minutes compared to general purpose lanes.

Those average trip numbers are compared “to the GP lanes during the same time frame Jan-March 2016,” which might be less about the efficiency of the express toll lanes, and how stymied the other lanes are by the loss of a lane which cannot be freely entered and exited except at certain choke points.

King County Metro is reporting a 10 percent increase on ridership on I-405 routes and 30 locations monitoring arterial routes parallel to I-405 have reported no significant change in traffic volume.

Recent changes to the lanes, including the weekend and holiday proviso which makes lanes free to all motorists, have seen a marked reduction in weekend congestion.

The Washington State Department of Transportation has claimed that a year was the true measurable date for the express lanes’ effectiveness.