press release:
Eastbound traffic on the Spokane Street Viaduct will be temporarily shifted onto the adjacent new viaduct structure at 5 a.m. on Thursday morning, April 12. The two lanes of eastbound traffic will join the two lanes of westbound traffic, which had previously been moved over to the new structure late last year. This shift of eastbound traffic is expected to remain in place until late this summer, when the Spokane Street Viaduct Widening Project is substantially complete.

It is necessary to move the eastbound traffic off of the old viaduct structure so that its bridge deck surface can be repaired and resurfaced, after which eastbound traffic will be returned to the then refurbished structure. During this temporary configuration, travel lanes will be 10 feet wide to accommodate four lanes of traffic. Once eastbound traffic returns to the refurbished structure, all lanes will be 11 feet wide in the permanent configuration. In the interim, the speed limit on the Spokane Street Viaduct will be 25 MPH (down from 35 MPH) for safety.

Either (or both) the First or Fourth Avenue off-ramps will be open during this period. During the initial phase of work starting April 12 and expected to last six to eight weeks, the Fourth Avenue off-ramp will be closed to all traffic. Motorists who would normally use this exit are instead asked to take the First Avenue S off-ramp and then proceed east on lower Spokane Street to Fourth Avenue S.

In addition, access to the eastbound Spokane Viaduct from the eastbound Harbor Island on-ramp will be restricted – the ramp will only provide access to northbound SR99—until the eastbound traffic is moved back onto the refurbished structure in the late summer.