Northbound I-5 bridge will carry both directions of traffic starting next week
ARLINGTON – The plan to have both directions of I-5 share the northbound Stillaguamish River Bridge is on hold again due to rain that is forecast for tonight and tomorrow. The Washington State Department of Transportation now hopes to implement the traffic shift starting at 10 p.m. either Thursday, July 24, or Sunday, July 27, the next available nights for the work.
Crews need dry pavement to stripe the crossover lanes that will carry traffic to the northbound lanes and bridge. When the shift is complete, both north and southbound drivers should expect delays as crews work during the next four months.
“We need drivers to help us keep traffic flowing even though the interstate is down to two lanes in each direction,” said Dave Crisman, Washington State Department of Transportation project engineer. “We expect delays at peak periods like Thursday and Friday afternoons and at times on weekends. But if drivers with more flexible schedules can adjust their travel times, it can help reduce congestion for everyone.”
Since Tuesday, July 8, each direction of I-5 has been reduced to two lanes to allow median crossover lanes to be built north and south of the river. The crossover lanes will allow southbound traffic to use the northbound bridge while contractor crews working for WSDOT the replace the 81-year-old deck of the southbound bridge. A concrete barrier wall will separate northbound and southbound traffic.
As the traffic shift is implemented, the crews will reduce southbound I-5 to one lane at 10 p.m. and shift traffic onto the crossover lanes. Southbound I-5 will remain one lane until 5 a.m., allowing the crews to restripe the interstate to guide traffic through the crossover. When the striping is complete, southbound I-5 will revert to two lanes using the crossover and northbound I-5 bridge. Northbound I-5 already is in its configuration for the project.
The speed limit through the work zone has been reduced from 70 to 55 mph.
Peak period congestion
The bridges combine to carry 80,000 vehicles a day, which can increase to about 100,000 vehicles a day on a busy summer weekend. Drivers should expect congestion through November, when the southbound bridge reopens. Delays of up to 35 minutes are possible during peak hours:
• Northbound I-5: 3 to 6 p.m. Thursdays and Fridays
• Northbound I-5: 11 a.m. to 4 p.m. weekends
• Southbound I-5: 11 a.m. to 6 p.m. weekends
Depending on the destination, some drivers may be able to use alternate routes, such as State Route 9 to the east or the Pioneer Highway to the west between Stanwood and Arlington.
When the southbound bridge closes to traffic, crews will remove the bridge deck to replace some of the steel framework. They will then install a new concrete and rebar deck. When work is completed in November, I-5 will be restored to three lanes in both directions.
The southbound I-5 Stillaguamish River Bridge originally was built in 1933 as part of US 99 and carried two lanes of traffic in each direction. It became part of I-5 when the interstate was built in the 1960s.
The northbound I-5 Stillaguamish River Bridge opened in 1971 and traffic shifted to separate bridges, improving safety and traffic flow on this section of I-5.