SR 504 is maintained by the Washington State Department of Transportation (WSDOT), which conducts an annual survey on state highways to measure traffic volume in terms of average annual daily traffic. Average traffic volumes on the highway in 2016 ranged from a minimum of 500 vehicles near Coldwater Lake to a maximum of 14,000 vehicles at the I-5 interchange in Castle Rock. SR 504 is the main route for a majority of the 3 million annual visitors to the Mount St. Helens area. It is designated by the state government as the Spirit Lake Memorial Highway, a state scenic byway, and a National Forest Scenic Byway by the United States Forest Service.