Lands Ecology Reserve, a restricted wildlife preserve that forms part of the Hanford Reach National Monument. SR 24 meets SR 240, a major highway connecting to the Tri-Cities, at the northeast corner of the reserve. SR 24 turns north at the junction and travels along the northwest edge of the Hanford Site, flanked by fences on both sides of the road. The highway descends from the plateau by turning west and returning to its northerly course, eventually reaching a rest area on the south shore of the Columbia River. SR 24 crosses the Columbia River on the Vernita Bridge, a steel truss bridge downriver from the Priest Rapids Dam. On the north side of the bridge in Grant County, the highway intersects SR 243, which travels along the Columbia River towards Mattawa and Vantage. SR 23 turns northeast and follows the south wall of the Wahluke Slope before traveling due east across the Saddle Mountain National Wildlife Refuge and into Adams County. The highway leaves the Hanford Reach National Monument and forms the boundary between Adams and Franklin counties for several miles, briefly turning to cross a section of the Saddle Mountains. Near the former Othello Air Force Station, SR 24 turns north and follows Radar Road through farmland on the outskirts of Othello. After entering Othello, the highway becomes Broadway Avenue and continues through an industrial area before terminating at an underpass with SR 26. The two highways are connected via an extension of 1st Avenue on both sides of the underpass. SR 24 is maintained by the Washington State Department of Transportation (WSDOT), which conducts an annual survey on the state's highways to measure traffic volume in terms of average annual daily traffic. The busiest section of the highway, at its interchange with I-82, carried a daily average of 23,000 vehicles in 2016; the least busiest section of the highway, northeast of the Vernita Bridge, carried only 1,100 vehicles. A short section between I-82 and Faucher Road in Moxee is designated as a MAP-21 arterial under the National Highway System, a network of roads identified as important to the national economy, defense, and mobility. History SR 24 was added to Washington's state highway system in 1937 as Secondary State Highway 11A (SSH 11A), which traveled from Primary State Highway 3 (PSH 3) and US 410 in Yakima to PSH 11 and US 395 in Connell. The highway was