Fuel-economy figures peaked last August at 25.8 mpg, but the bigger picture still shows a positive trend in recent years. Fuel economy is up 26 percent since UMTRI started tracking these numbers almost eight years ago. But those numbers appear to be plateauing, at least for now. We'll get a much better picture of where things go from here once the 2016 model-year advanced-powertrain vehicles start sales this fall.
The culprit may be the somewhat waning interest in hybrids, plug-in hybrids and battery-electric vehicles. Last month, Americans bought almost 49,000 green cars, which was down about 16 percent from a year earlier. Plug-in vehicle sales plunged 22 percent to about 8,600 units, as Americans appeared to be waiting for new versions of the Nissan Leaf battery-electric and Chevrolet Volt extended-range plug-in as well as other new models to come out. Through the first seven months of the year, green-car sales in the US declined 16 percent from a year earlier to more than 312,000 units. Plug-in vehicle sales fell 11 percent to 59,943 units. Take a look here for more details on UMTRI's fuel-economy study for July.