 A roundabout at SR 9 was opened to traffic in November 2012, replacing a signalized intersection that had been the site of frequent collisions.A second roundabout was added at 23rd Avenue west of the I-5 interchange, using funds from a private developer to support their new shopping center and apartment complex.In the late 2000s, WSDOT also studied $57 million in traffic and safety improvements for the SR 531 corridor near the Arlington Municipal Airport, recommending that the highway be widened to four lanes and include bicycle lanes, sidewalks, and roundabouts at certain intersections.