This image shows U. S. Highway 40 as it passes through the Bonneville Salt Flats from Salt Lake City to Wendover, Utah.
The description states:
BONNEVILLE SALT FLATS
U. S. Highway 40 and 50 crosses this famous Bonneville Salt Flats “World’s Fastest Speedway” in the Western edge of Utah. Salt for commercial purposes is harvested annually.
–Because of concerns that the flats may be affected by salt mining, the flats are now flooded annually with water from the southern salt beds to provide additional smooth surfacing.
This card likely dates from the 1950s.