David Johnson, a project manager at Western Archaeological Services in Rock Springs, has worked in archaeology in Wyoming, western Colorado and northeastern Utah since 1984, specializing in historical archaeology. He has conducted excavations at sites including South Pass City, the Nevin Homestead in Carbon County and the Carbonera coal mine and townsite in Garfield County, Colorado. He has also recorded long sections of historic trails including the Overland Trail in Carbon and Sweetwater Counties, the Cherokee Trail in Carbon and Sweetwater Counties, the Lincoln Highway, the Rock Springs to Browns Park Road, the Rawlins to Baggs Road, The Denver and Rio Grande and Rio Grande Western narrow gauge railway in Colorado, and the Opal Wagon Road.