ST. PETERS, Mo. (AP) _ Trying to avoid a speeding ticket in St. Peters? Ditch the radar detector, and get a calculator.

Preparing for a national change that may never occur, the city this week posted six new speed limit signs in metric along one street.

″I thought, ‘There’s got to be some mistake,’ ″ said Pauline Paszko, who works at a library along Spencer Road, where the speed limit is now 60 kilometers per hour - or 37 mph.

St. Peters, which has about 45,000 residents and is 15 miles west of St. Louis, is probably the first town in the nation to use metric-only signs, according to Gary Carver, director of the metric program for the National Institute of Standards and Technology.

″We’re pretty progressive here in St. Peters,″ said Dale Houdeshell, the city’s public works chief.

Maybe too progressive. Houdeshell claimed that the federal government requires every highway sign to be changed by 1996. But Carver said that’s not the case.

By 1996, departments have to convert all their construction documents to metric, measuring concrete in kilograms instead of pounds, for example. But there is no requirement to change road signs.

Such quibblings won’t stop the city’s metric march. Workers are scheduled to install more signs on Spencer Road when they extend it north this summer. In the fall, metric signs will be installed on two other roads.

Some drivers think the switch is immeasurably foolish.

″I think it’s really, really stupid,″ Peggy Johnson said. ″Somebody who’s not thinking rationally is going to look at that and think they can go 60 mph.″