Highway 70 Widening

Benton, Arkansas

Michael Baker provided environmental and design services for a widening project of U.S. Highway 70 between Interstate 30 and the city of Hot Springs, Ark. This $78.5 million construction project for the Arkansas Department of Transportation (ARDOT) expanded the 19-mile stretch of highway from two lanes to five, reconstructed four bridges, constructed 20 box culverts, and signalized a key intersection to improve safety for both local and through traffic.

During the initial construction of Highway 70 in 1956, additional right of way was purchased to accommodate the future construction of a four-lane divided highway; however, the majority of the right-of-way was never cleared or graded for this anticipated improvement. As traffic volume increased on Highway 70 through the Ouachita Mountains, so did the number and severity of accidents due in part to limited roadway width, narrow shoulders and clear zones, as well as limited sight distances due to rolling terrain, tight curves and dense forest.

Our team was tasked with correcting portions of the roadway that didn’t meet current standards for horizontal and vertical alignments, while minimizing right-of-way impacts, environmental impacts and costs. We recommended construction of a five-lane section, which was accomplished by widening the roadway on both sides and generally following the original centerline, where possible. This approach helped to lower costs by leveraging the existing pavement and embankment while reducing the amount of cut and fill required through the rugged landscape. The solution also resulted in minimal additional right-of-way acquisition, since a modern divided highway is much wider than the right of way acquired during the 1956 construction.

The enhanced corridor, which significantly improves safety and mobility through the addition of lanes, widened shoulders and increased sight distances, was formally opened to traffic at a ribbon-cutting ceremony on June 1, 2018.