They may be working together on a separate educational program to develop hybrid technologies, but buyers considering used cars in New Jersey may be interested in learning that the Environmental Protection Agency is distancing itself from General Motors’ claim that its new Chevrolet Volt hybrid could get 230 miles per gallon in certain situations.

“The EPA has not tested a Chevy Volt and therefore cannot confirm the fuel economy values claimed by GM,” an administration spokesperson said in a statement. The official did go on to say that the EPA was glad that the automaker was making efforts to develop fuel efficient technology.

There may be one other problem for buyers looking at the Volt, slated to go on sale later next year: it’s expected to cost $40,000, and is not much more efficient than some diesel cars after 200 miles.

For example, used Volkswagen Golfs in New Jersey can get more than 50 miles per gallon, dependent on driving style, not far off from the Volt’s estimated mileage over 200 miles and many are priced at less than half of the price of a new Volt, reported the Atlantic.