Manhole covers stolen!

Manhole covers and sewer grates are disappearing all over Indianapolis.

"This is a severe public safety hazard we have here," said Margie Smith-Simmons,
a spokeswoman for the city's Department of Public Works. "These manholes range
in depth from 4 feet to 30 feet deep."

Yeah, I see how this could be a major problem. How are the public works crews supposed to tell the potholes from the open manholes?