So-called "rush hour" traffic now lasts six or more hours on some key Portland-area highways, according to a new report from the Oregon Department of Transportation.

The agency found that the hours of congestion in the Portland area grew by 13.6 percent from 2013 to 2015.

The metro area's population grew 3 percent, to 2.4 million, during that span, but an economy on the upswing has put far more vehicles on the road. Vehicle-hour delays were up 22.6 percent.

"Traffic congestion in the Portland region can now occur at any hour of the day, including holidays and weekends," the report said. "It is no longer only a weekday peak hour problem."

Eastbound U.S. 26 inbound saw the biggest change over the two-year span. Congestion now begins at 6:15 a.m. and continues straight through until 7:45 p.m. That route's morning commute's congestion previously dissipated around 9:15 a.m., with traffic picking up again at noon.

The report also found congestion duration had increased by two hours during the evening commute on Interstate 5 southbound into the Rose Quarter.

Drivers also now encounter three hours of delay on Interstate 205 northbound between the Interstate 5 junction and the Abernethy Bridge, which crosses the Willamette River between West Linn and Oregon City.

The findings come as little surprise to daily auto commuters.

I shifted my schedule to be on the road at 5:30am on the way to work. But leaving at 3pm doesn't help much on 217. It's just always jammed. — RandomProperNoun (@RandomNoun7) August 2, 2017

Two years ago Bill Hurt of Oregon City moved to a work schedule that would allow him to leave his Lake Oswego employer by 3 p.m. in an effort to spend more time with his family.

That helped until he switched jobs. Now working in Beaverton, his commute on Oregon 217 is jammed daily.

"Even at 3 p.m., there's a reasonable amount of traffic," he said. "If I leave late at 3:30, or even on a bad day at 4 p.m., I know I'm not going to get home until 5:30, 5:45."

This year I switched to bike + max which has made my 8 mile commute more fun, fast and easy. Driving in traffic was so stressful! — Jenya Andreev (@andjenya) August 2, 2017

A transportation package approved by the Oregon Legislature last month tees up funding to add lanes in the Rose Quarter and replace the Abernethy Bridge, both paid in part with rush-hour tolls.

It also would add auxiliary lanes -- which connect one interchange ramp to the next, smoothing the flow of traffic -- to Oregon 217. The transportation department plans to add auxiliary lanes to other area freeways, as well.

Joe Cortright, a Portland economist, said those projects to address "bottlenecks" are unlikely to do much to address congestion in the long run, though they might reduce unexpected delays due to crashes.

Instead, he said, the tolls themselves are more likely to reduce congestion.

"Among economists, there's this growing recognition that if you really want to eliminate congestion, the only way to do it is by pricing the roads," he said.

In addition to tolls, the suite of transportation funding measures also includes a gas tax hike, high vehicle registration fees, a payroll tax and taxes on new cars and bicycles.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus