California wants 1 million electric vehicles on roads by 2020 | detnews.com | The Detroit News

Many environmental groups want the Obama administration to require a fleetwide average of 60 mpg by 2025 for cars and light trucks. Automakers note they already agreed to a fleetwide average of 35 mpg by 2016 -- four years ahead of a congressional mandate.

"Before we have even achieved those new heights, the calls have begun to almost double mileage," said Dave McCurdy, president and CEO of the Alliance of Automobile Manufacturers, the trade group representing Detroit's Big Three automakers, Toyota Motor Corp. and seven others. "Instead of plucking numbers out of the air, we should base policy on science."