Runs from I-15 in Barstow, CA to the Arizona State Line at Topock, AZ and east to Wilmington, NC
I-40 runs across the vast expanse of the Mojave Desert through California. Former US 66 follows the freeway, except for the portion through the Bristol Mountains, where US 66 headed south to follow an easier path around them. In the early 1960’s, studies were undertaken to use underground nuclear bombs to excavate a path through the Bristol Mountains. This path would have been deep enough and large enough to allow for the realignment of the railroad as well as the highway. This project, known as Project Carryall, was never implemented. It does remain, however, as one of the more interesting roadway construction plans in the state. The first segment of I-40 was opened in 1961, the last in 1972.