Low Ceiling!

Low-flying aircraft warning in St. Louis County, Mo. (westbound I-70)
Photos courtesy of Rich Piehl (taken 2006)

The opening of the new runways at Lambert Airport prompted MoDOT to put up these warning signs on Interstate 70 in St. Louis County. There's a pair of them for each direction passing by the airport, westbound (above) and eastbound (below). In the westbound shot you can also see the VMS (variable message sign) which is immediately in front of the airport.

Low-flying aircraft warning in St. Louis County, Mo. (eastbound I-70)