WSDOT began preparing to install a median barrier and widen SR 502 to four lanes between the I-5 interchange and the western Battle Ground city limit in July 2012 to accommodate increasing traffic on the highway, which has a speed limit up to . Construction for the $85 million project began in earnest in 2014. New Mill Creek wetlands were created, to mitigate for wetlands buried by construction, which included the driving of 1,200 concrete pilings. The new, four-lane highway, which includes shoulders for bicycle and pedestrian travel and traffic signals at major intersections, opened on June 27, 2016.