A state highway to be known as state route number 528 is established as follows:
Beginning at a junction with state route number 5 near Marysville, thence easterly to a junction with state route number 9. Until such time as state route number 528 from Marysville to a junction with state route number 9 is actually constructed on the location adopted by the department, no existing city streets or county roads may be maintained or improved by the department as a temporary route of state route number 528.
RCW 47.17.750