Clarkston. SR 124 is maintained by the Washington State Department of Transportation (WSDOT) and designated as part of the Lewis and Clark Trail Scenic Byway, a state scenic byway. A short section of the highway in Burbank is also listed on the National Highway System. WSDOT conducts an annual survey of average traffic volume on the state highway system that is measured in terms of average annual daily traffic. Traffic volumes on SR 124 range from a minimum of 1,400 vehicles between Prescott and Boles to a maximum of 7,000 vehicles near Hood Park in Burbank. History Most of the current route of SR 124 follows a portion of the Lewis and Clark Trail. The highway from Piper Canyon Road to Waitsburg follows a small section of the route that Lewis and Clark took from Fort Clatsop in May 1806 before splitting in Montana. SR 124 became a state highway during the 1964 highway renumbering, in which the Washington State Department of Transportation (WSDOT) replaced the old system (Primary and Secondary Highways) with a new system (State Routes), which is still in use today. In the Primary and Secondary system, SR 124 from US 12 to SR 125 (then US 410) was Secondary State Highway 3D and SR 124 from SR 125 to SR 126 was Secondary State Highway 3E. Secondary State Highway 3D (SSH 3D) was added in 1937, during the creation of the Primary State Highway system. The original route started at US 410 in Touchet and went north to Eureka and east to SSH 3E west of Prescott. Later in 1951, SSH 3D was moved to a route from US 410 in Burbank to SSH 3E, the current route of SR 124 and in 1965, the route from Burbank to Ice Harbor Road was designated the Ice Harbor Drive. SSH 3E was also added in 1937 and went from US 410 in Walla Walla north to SSH 3D and east past Prescott to Waitsburg. SSH 3E became SR 125 from Walla Walla to SSH 3D and SR 124 from SSH 3D to Waitsburg. Before and after the establishment, the route of SR 124 has gone through several documented WSDOT construction projects from 1941 to 2004. Many were small, minor projects including repavings and intersection improvements. The first was a construction project that constructed SSH 3E from SSH 3D to Waitsburg, which took place in 1941. The latest