Motorists on Shepard Road in St. Paul got an obscene message from an electronic road side sign instead of the information that was supposed to warn them of a flood-related closure ahead.

Sometime on Tuesday night, a hacker changed the message on the board near Chestnut Street to read "Local Moms Need [a man's body part]." The vulgar message generated several calls to the city, said Kari Spreeman, a public works department spokeswoman

"With the obscenity, sure we did get some calls," she said. "As soon as we found out, we got them removed."

The temporary sign was provided by Safety Signs of Lakeville. The Drive put in calls to the company to find out how the nefarious message could have gotten on the sign, but have yet to hear back.

The stunt does not seem to be just a local phenomenon. Just last month, the Homeland Security Department cautioned transportation operators about a security hole in some electronic freeway billboards that could let hackers display bogus warnings or illicit messages to drivers.

In California, somebody hijacked a sign to read "Godzilla Attack - Turn Back" and to tease North Carolina drivers with the message "Hack by Sun Hacker."

DHS said some of the signs involved were made by Daktronics, although it was not immediately known if the one in St. Paul was.

In an alert issued last month, DHS said the ease of cracking a password or default logons could be part of the problem. Officials told users to "review sign messaging," update passwords and secure communication paths to the signs.