Interstate 405 North begins with two thru lanes at Exit 299B on Interstate 5 North. (Photo taken 9/22/19).

Interstate 405 North approaching Exit 1A on the left. (Photo taken 9/22/19).

Interstate 405 North at Exit 1A: City Center / South Waterfront (Photo taken 9/22/19).

View on Interstate 405 North in Portland. (Photo taken 9/22/19).

Take Exit 1B to Keller Auditorium. Take Exit 1C to Portland State University. (Photo taken 9/22/19).

Trucks with hazardous materials are prohibited on US 26 West in Portland. (Photo taken 9/22/19).

Interstate 405 North at Exit 1B: 4th Ave (Photo taken 9/22/19).

Take Exit 1D to the Zoo and Forestry Center. (Photo taken 9/22/19).

Interstate 405 North at Exit 1C: 6th Ave (Photo taken 9/22/19).

Take Exit 1D to 12th Ave. (Photo taken 9/22/19).

Interstate 405 North at Exit 1D: US 26 West - Beaverton (Photo taken 9/22/19).

The speed limit on Interstate 405 North in Portland is 50 mph for all traffic. (Photo taken 9/22/19).

Take Exit 2A to the Oregon History Museum and Portland Art Museum. (Photo taken 9/22/19).

Interstate 405 North at Exit 2A: Salmon St / Providence Park (Photo taken 9/22/19).

Take Exit 2B to Rose Quarter. (Photo taken 9/22/19).

Overhead Interstate 405 North reassurance signage. (Photo taken 9/22/19).

Interstate 405 North at Exit 2B: Everett St / Glisan St (Photo taken 9/22/19).

View on Interstate 405 North as it passes under Couch St in Portland. (Photo taken 9/22/19).

Mile marker 2 on Interstate 405 North in Portland. (Photo taken 9/22/19).

Advance signage for Exit 3, which is about 1/4 mile ahead on the left. The leftmost lane will become an Exit Only lane for Exit 3. (Photo taken 9/22/19).

Interstate 405 North at Exit 3: US 30 West - St. Helens (Photo taken 9/22/19).

Ahead, Interstate 405 North will cross the Willamette River on the double-decked Fremont Bridge. The northbound lanes of I-405 will use the lower deck. (Photo taken 9/22/19).

A view of the Fremont Bridge from Interstate 405 North, looking to the northeast. (Photo taken 9/22/19).

Interstate 405 North as it curves to the northeast and begins crossing the Fremont Bridge via its lower deck. Ahead, traffic from US 30 East will merge into I-405 North from the left. (Photo taken 9/22/19).

Interstate 405 North as it crosses the Willamette River via the lower deck of the Fremont Bridge. (Photo taken 9/22/19).

The left lane on the Fremont Bridge's lower deck will become and Exit Only lane to Interstate 5 South while the rightmost lane will become an Exit Only lane to Kerby Ave. Traffic to Interstate 5 North toward Seattle must use the center two lanes. (Photo taken 9/22/19).

Keep left and take the ramp to Interstate 5 South to get to Interstate 84 East and to remain on US 30 East toward The Dalles. (Photo taken 9/22/19).

More overhead signage showing that the leftmost lane and rightmost lane will become Exit Only lanes ahead to Interstate 5 South and Kerby Ave, respectively. (Photo taken 9/22/19).

Interstate 405 North at Exit: Interstate 5 South (Photo taken 9/22/19).

Interstate 405 North at Exit: Kerby Ave (Photo taken 9/22/19).

As Interstate 405 approaches its northern terminus, its two remaining thru lanes become the ramp to Interstate 5 North. (Photo taken 9/22/19).

View on Interstate 405 North as its two remaining lanes curve to the north in preparation for merging into the northbound lanes of Interstate 5. (Photo taken 9/22/19).

Another view on Interstate 405 North as it reaches the northeastern end of the Fremont Bridge and prepares to terminate at the junction of Interstate 5 North. (Photo taken 9/22/19).

The ramp maintains its two lanes as Interstate 5 North traffic comes into view ahead. (Photo taken 9/22/19).

The ramp from Interstate 405 North joins Interstate 5 North just to the south of Exit 303. (Photo taken 9/22/19).