I-5 closure in Portland over weekend will cause issues with Clark County trafficUpdated 20 hours ago

The full closure of Interstate 5 just south of downtown Portland this weekend could snarl traffic as far north as Vancouver.

Drivers should expect long delays and big backups, especially along I-5, throughout the weekend.

Starting at 9 p.m. Friday, all lanes of I-5 will close in both directions for 4 miles between Terwilliger Boulevard and the Capitol Highway exits.

All lanes will reopen by 5 a.m. Monday.

“Any time you take I-5 out of action, it’s going to cause a ripple effect up and down the line,” said Don Hamilton, spokesman for the Oregon Department of Transportation. “This closure is a good distance from the Columbia River, but it is no doubt going to be felt on I-5 in Clark County.”

Drivers can use major Portland-area highways as detours, including Interstate 205, Interstate 84, Oregon Highway 217 and U.S. Highway 26. Southwest Barbur Boulevard will be available for local traffic.

Hamilton said drivers planning on using Interstate 5 this weekend between Vancouver and Portland should consider taking I-205 instead.

“Surely anybody coming from Clark County heading south into Portland should take I-205. That would be the wise move,” he said. “Plan ahead and be aware, because this is going to cause some serious delays.”

The closure is part of the construction of a new I-5 bridge deck over Southwest 26th Avenue.

Work on the project began nearly a year ago using a construction method that builds the new bridge underneath the existing bridge. This method allowed I-5 to remain open during construction for all but this weekend.

This approach saves an estimated $5.5 million in costs and six months of construction time, and all efforts were made to keep the closure to as little time as possible, according to ODOT. The estimated project cost is $13 million.

“We chose the option with lower costs, shorter construction time, fewer traffic impacts, less nighttime noise, fewer environmental impacts, and improved safety for workers and drivers,” a fact sheet about the project states. Other construction methods could have created major traffic impacts on I-5 for nearly two years, according to the fact sheet.

The I-5 bridge over 26th Avenue was built in 1959 and widened in the 1980s. It carries more than 100,000 vehicles per day, and its deck is heavily worn. This project will bring the bridge up to today’s seismic standards and create a smoother ride for travelers.

The project may include occasional nighttime single- and double-lane closures in both directions in the months ahead. Those closures have not been scheduled.

To learn more about the project, visit https://www.oregon.gov/odot/projects/pages/default.aspx.