You can read a summary of the report here by the Washington Post. The fuel efficiency target of 54.5-miles-per-gallon was set at a time when gas prices were high and there was a strong push for carmakers to produce cars with better fuel efficiency.

But if gas prices remain at current levels and sales of pickups and SUVs continue to rise then it's likely, as the report states, the 54.5-miles-per-gallon target won't be met by 2025. So, does that mean the 2025 fuel efficiency standard should be scraped or revised downwards? 

On the contrary, the 2025 target may still be achieveable by using higher blends of ethanol.

The Department of Energy's 2015 Quadrennial Technology Review specifically identifies ethanol blends from E25 to E40 "would dramatically increase the octane rating of finished gasoline."

"Higher-octane fuel would enable downsizing, downspeeding and charge air boosting of the engine to improve the fuel economy of the vehicles," it said.

In fact, it said, if all vehicles had high compression ratios and could use up to 40 percent ethanol, petroleum usage per vehicle would reduce by 30 percent while there would 149 million metric tons of annual greenhouse gas reductions. You can read more here.

At present, only flex-fuel vehicles (FFVs) can use ethanol blends that contain over 15 percent ethanol. But as we discovered earlier this year, the 2016 MINI Hardtop and 2016 BMW X1 have been approved for the use of E25 despite the fact that neither one is an FFV according to BMW AG. 

As such, if two non-FFVs with small displacement turbocharged engines can run on E25 and more carmakers rollout models with similar engines (all carmakers have turbocharged engine technology), perhaps it's time for the government to consider E25 to E40 as the new standards.