In the next few days, at least three major construction closures will cause traffic jams, and even botched appointments for drivers who are unprepared.
In Seattle, the ramps connecting Mercer Street to Interstate 5 will be closed from 11 p.m. Friday to 5 a.m. Monday so workers can install storm drains, utility wires, and concrete to prepare for a freeway-ramp rebuild where Mercer flows into I-5. The Union Street onramp to northbound I-5 will also be closed. Denny Way is likely to be more crowded than usual.
The Spokane Street Viaduct between the West Seattle Bridge and I-5 will have night closures next week. Traffic will exit at Harbor Island and continue over the lower swing bridge to West Seattle, from 2 a.m. to 5 a.m. Tuesday, and from 9 p.m. Wednesday until 5 a.m. Thursday. Then on Thursday night, the whole road from I-5 to Highway 99 will be closed westbound at 10 p.m., until 5 a.m. Friday morning. Also, one of the two eastbound lanes Thursday night will be closed from 9 p.m. to 5 a.m. from Highway 99 to I-5. Drivers can bypass the traffic jams by taking Highway 99 between downtown and West Seattle.
On the Eastside, overnight lane closures on southbound I-405 are planned Friday and Saturday to repair a Kirkland pedestrian bridge, where an over-height vehicle damaged steel girders in January. Both nights, the first lane will close at 8 p.m. until the three left lanes are to be closed by 11 p.m., to reopen at 7 a.m.
A longer list of road closures is posted by the state Department of Transportation here.