It's an expensive problem. Public Works Director Kara Buzanoski says the cost of replacing them is about $15,000.
Buzanoski and police Chief Mark Leahy suspect teenage pranksters, but so far there have been no arrests.
The town had a similar problem a few years ago when several teens were apparently involved in a contest to see how many signs they could purloin. When police started closing in on those culprits, the signs started reappearing.
Leahy says this time the thieves will be prosecuted.
The town will replace the stolen signs. Buzanoski says the new ones are more vandal-resistant.