A report by CNBC highlights questions about the accuracy of U.S. government certification of electric-vehicle range.

The news provider says Environmental Protection Agency testing and certification of EVs has drawbacks: it’s tested them since just 2012; some private groups say their test results vary from the EPA’s; and the agency’s labels differ from gas-powered vehicles’ labels because they don’t consider how people drive EVs.

CNBC said labeled ranges also appear longer than they are in reality and that carmakers can take steps to inflate their models’ range specifications.

Since EV technology is still new, that can also affect how numbers are arrived at, CNBC said. It indicated that some industry experts say EPA ratings are more accurate than those of other government testers.

To learn more, watch CNBC's video.