May 20, 2003
Iowa switched from single letters on its county roads to the alphanumeric grid system around 1969. For a short period, the new designations were printed on the same green squares, probably until counties exhausted their supplies.
One marker for Benton County Road K, today known as V42, survived into the 21st century. This sign was a short distance south of E22. On July 11, 2011, a “derecho” swept through and flattened everything in its path from Garwin to Vinton. Neither Jason Hancock nor I have seen the sign since. Iowa’s oldest surviving county road marker has been whisked away.