The Washington State Department of Transportation is advising Interstate 90 commuters to change their habits as work begins Friday, July 18 to replace aging bridge expansion joints westbound on the East Channel Bridge.

“People need to make a choice because we don’t need people doing what they used to do for a normal commute, because it’s not going to be normal,” said Bart Treece, a WSDOT spokesman.

Starting at 9:30 p.m. tonight, transportation crews will begin replacing two 92-foot-long, 29-ton expansion joints — under 11 inches of concrete — on the East Channel Bridge, which is anticipated to close up to three westbound lanes on I-90, starting at Bellevue Way Southeast. Project engineers estimate more than half of the 85,000 daily commuters on westbound I-90 will need to find an alternate route. The I-90 HOV lane will be open to all traffic between I-405 and the east entrance to the center roadway. The closures are expected to last until 5 a.m. July 25.

Treece said this project will cause regional traffic issues, and motorists should expect backups on I-405, State Route 520 and also I-5 in Seattle. Those who can are encouraged to carpool, vanpool, telecommute, seek alternate routes or drive during off-peak travel times. As motorists are being asked to add an hour to their commutes, peak times are also expected to be longer, added Treece.

Engineers estimate the best times to travel at before 6 a.m., between 11 a.m. and 2 p.m. and after 7 p.m.

Those considering taking SR-520 are encouraged to set up a short-term Good To Go! account, as the bridge there will remain tolled during the project. Treece said waiving tolls is up to the state transportation commission to decide.

WSDOT has also published an I-90 survival guide on its blog, which offers detailed advice for dealing with this traffic disruption: http://bit.ly/1okf5p0