More electric cars means finding new standards to measure fuel efficiency

More electric cars means finding new standards to measure fuel efficiency

It used to be easy to know whether a car was a glutton for fuel. Federal standards defined miles per gallon and laid out precisely how the statistic should be measured. But with the dawning of what enthusiasts hope is an era of electric cars, federal regulators are struggling to come up with a definition of auto efficiency for the next generation of technology. This year, two major auto