Crews shut down the express lanes on the Interstate 90 floating bridge at 11 p.m. Sunday, and they will remain shut for up to 19 days. (Check live cameras and maps in our traffic section.)

The closure will add an average of about 30 minutes to the westbound commute over the bridge during the morning hours and to the eastbound commute during the evening hours, according to the state Transportation Department.

The closure is need to replace the aging expansion joints on the bridge, which carries thousands of vehicles across Lake Washington - day in and day out.

The 40-ton expansion joints on the express lanes and the westbound bridge deck are all 20 years old, cracking badly and in need of replacing.

Project Designer Ralph Dornsife says if the joints aren't replaced, they could break and then "you would end up with gaps in the roadway which could obviously present safety issues to motorists."

The closure is scheduled to last through May 23, but it could be finished early. Mike Murphy of the state DOT says the contractor has a $40,000-a-day incentive to finish the project ahead of schedule.

The westbound bridge deck will be closed for similar work from July 5 to 28.

Because of the lane closures, commute times from Bellevue to Seattle during May and July could increase from 10 minutes to over an hour.

Murphy says all commuters should consider working from home, biking to work, or joining a vanpool.

"If you sign up to start a new vanpool before May 15th you can get three months for free," he said.

The project supports more than 80 jobs, and will cost an estimated $8.3 million to be paid for with federal transportation money.

More information here »