ANN ARBOR, Michigan — The average fuel economy for new vehicles sold in September dropped to 25.2 mpg, according to researchers Michael Sivak and Brandon Schoettle of the University of Michigan Transportation Research Institute.
The September average is down 0.1 mpg from last month, and 0.6 mpg less than the peak reached in August 2014, but still 5.1 mpg better than October 2007 when the researchers first began compiling data.
The latest UMTRI Eco-Driving Index stands at 0.82, indicating that the average new vehicle produced 18 percent lower emissions than in October 2007, although that number is 4 percent higher than the record low reached in August 2014.
To arrive at its figures, UMTRI calculates average sales-weighted fuel economy from the monthly sales of light-duty vehicles (cars, SUVs, vans and pickups) and the combined city/highway fuel economy ratings that appear in the EPA Fuel Economy Guide and on vehicle window stickers.
According to UMTRI the continued decline in fuel economy "likely reflects the decreased price of gasoline in September, and the consequent increased sales of pickup trucks, SUVs and crossovers."
As previously reported by Edmunds, September's sales leaders included trucks, such as the Chevrolet Silverado, Ford F-Series, GMC Sierra and Ram pickups, as well as SUVs like the Buick Encore, Ford Explorer, Honda CR-V, Jeep Cherokee, Nissan Rogue and Toyota RAV4.
According to the AAA Daily Fuel Gauge Report, the average price of a gallon of regular unleaded gasoline nationwide was $2.29 on Tuesday, versus $3.28 a year ago.
AAA says that gas prices are the lowest they've been in seven months and estimates that American consumers are spending a total of $350 million per day less on fuel than they did last year.
"Drivers continue to enjoy substantial savings at the pump, but even bigger savings could be in store," said AAA spokesperson Avery Ash in a statement. "Barring any major supply disruptions, the national average could even test the $2 per gallon benchmark before the end of the year for the first time since 2009."
Part of the reason for the relatively low fuel prices, according to AAA, is that gas stations in many parts of the country switched over to less expensive winter-blend gasoline on September 16.
Another factor is the decreased cost of crude oil, which stands at about half the per-barrel price compared to a year ago, due primarily to "abundant oil production and a weaker global economy," as well as a plentiful U.S. oil supply, which is about 28 percent higher than this time last year.
Edmunds says: Low fuel prices continue to prompt American consumers to drive sales of SUVs and trucks.