During construction work in the summer of 2007, traffic on westbound Interstate 255 in St. Louis County was required to take a detour between its interchanges with Missouri 231 and US 50. The detour was required because left turns were prohibited at the end of the freeway exits to allow for reconstructing the Missouri 231 overpass over the freeway.
On these signs, note the unusual shape of the Missouri state outline, apparently similar to one used for Missouri 350 in Kansas City in 2003. Also note the nonstandard fonts, probably Helvetica, and the large size of the Interstate 255 marker and the use of a rectangular sign blank rather than a cutout marker.
To add to the significance of this scene, the permanent sign indicating the end of Interstate 255 and the beginning of Interstate 270 is in this photo, too.