They called them the the “Sand Hills west of Yuma,” but today they’re known as the Algodones Dunes, the 270 square miles of sand dunes in Imperial County.
The road, then U.S. 80 and now Interstate 8, was rebuilt during 1960-61 and the Jacob Dekema, who was the longtime director of Caltrans Region 11 (and recently passed away) wrote an article for California Highways and Public Works about the history of the road and the then-new improvements.
Dekema goes all the way back to the Spanish explorers and includes a great tidbit on wagon trains during the 1849 California gold rush.
“Attempts to cross the Sand Hills were all unsuccessful; legends exist regarding the loss of entire wagon trains in the moving, restless sand,” he wrote in the July-August 1961 edition, retrieved from archive.org.
The photo above is from the same article; it shows the road in 1916 when it was nothing more than wooden planks.