sentences:  The roundabout at SR 9 was constructed in 2007 while the Riverside Drive intersection was widened in 2009.State Route 538 (SR 538) begins at the (I-5) interchange in northern Mount Vernon located south of the Skagit River.The roadway, which handled a daily average of 27,000 motorists at the interchange in 2008, is named College Way and travels east through a commercial zone, passing Riverside Drive, the former route of (US 99), and crossing a set of rail tracks used by BNSF Railway.