Wash. Rev. Code § 47.20.635
No action may be taken by the department for the acquisition of real estate, rights, and interests for the approach and underpass to the University of Washington unless and until the city of Seattle, through its legislative authority, enacts an ordinance providing that the city of Seattle will, within three months after the necessary real estate, rights, and interests have been secured by the state as provided in this chapter, begin the work of grading, paving, and such other work as is necessary to complete and render available for use of the public, the approach and underpass and approaches to the underpass; and further providing that the city of Seattle shall thereafter keep and maintain the approach and underpass and approach to the underpass in a good state of repair and suitable for public travel and use, which construction and maintenance work the city of Seattle is hereby authorized and empowered to do and perform.
RCW 47.20.635