Vehicle fuel economy falls again in May

Jun 06, 2012 by Bernie DeGroat

(Phys.org) -- For the second straight month, fuel economy of all new vehicles sold in the U.S. fell by 0.2 mpg—likely reflecting a slight drop in gas prices, say researchers at the University of Michigan Transportation Research Institute.

Average (window-sticker values) of cars, light trucks, minivans and SUVs purchased in May was 23.7 mpg—down from 23.9 in April and 24.1 in March—but still the fourth-best month on record and up 3.6 mpg (18 percent) from October 2007, the first month of monitoring by UMTRI researchers Michael Sivak and Brandon Schoettle.

In addition to average fuel economy, Sivak and Schoettle issued their monthly update of their national Eco-Driving Index, which estimates the average monthly emissions generated by an individual U.S. driver. The EDI takes into account both vehicle fuel economy and distance driven—the latter relying on data that are published with a two-month lag.

During March, the EDI stood at 0.83, worse than the 0.81 mark in February, but the same as in January (the lower the value, the better). The index currently shows that emissions of greenhouse gases per driver of newly purchased vehicles are down 17 percent, overall, since October 2007.

Finally, Sivak and Schoettle report the unadjusted Corporate Average Fuel Economy performance. This index is based on a different set of EPA ratings than window-sticker values.

For May, unadjusted CAFE performance was 29.1 mpg, down from 29.3 in April and 29.6 mpg in March, but an increase of 18 percent (4.4 ) since October 2007.

Explore further: Solar energy prices see double-digit declines in 2013, trend expected to continue

More information:
Fuel economy calculations, along with a graph and table of current and recent mpg: www.umich.edu/~umtriswt/EDI_sa… es-weighted-mpg.html

Eco-Driving Index calculations, along with a graph and table of current and recent values: www.umich.edu/~umtriswt/EDI_values.html

Unadjusted CAFE performance, along with a graph and table of current and recent mpg: www.umich.edu/~umtriswt/EDI_sa… s-weighted-CAFE.html

add to favorites email to friend print save as pdf

Related Stories

Fuel economy slipped as gas prices dipped throughout April

May 09, 2012

(Phys.org) -- After recently topping 24 miles per gallon for the first time ever, fuel economy of all new vehicles sold in the United States slipped back below that mark last month, say researchers at the University of Michigan ...

Fuel economy of new vehicles continues to rise

Dec 06, 2011

(PhysOrg.com) -- Average fuel economy of all new vehicles sold in the United States is up for the second straight month, say researchers at the University of Michigan Transportation Research Institute.

Gas mileage of new vehicles at all-time high

Feb 14, 2012

(PhysOrg.com) -- Fuel economy of all new vehicles sold in the United States last month was at its highest mark ever, say researchers at the University of Michigan Transportation Research Institute.

Fuel economy of new vehicles slipped in December

Jan 11, 2012

(PhysOrg.com) -- After two months of increases, the average fuel economy of all new vehicles sold in the United States fell by a half mile per gallon last month, say researchers at the University of Michigan ...

Recommended for you

First-of-a-kind supercritical CO2 turbine

Oct 20, 2014

Toshiba Corporation today announced that it will supply a first-of-a-kind supercritical CO2 turbine to a demonstration plant being built in Texas, USA. The plant will be developed by NET Power, LLC, a U.S. venture, together w ...

Drive system saves space and weight in electric cars

Oct 17, 2014

Siemens has developed a solution for integrating an electric car's motor and inverter in a single housing. Until now, the motor and the inverter, which converts the battery's direct current into alternating ...

User comments : 6

Adjust slider to filter visible comments by rank

Display comments: newest first

dschlink
5 / 5 (1) Jun 06, 2012
If even a small fraction of the effort expended on boosting horsepower in engines over the last two decades had been devoted to improving mileage, the U.S. would be exporting oil today.
Eikka
1 / 5 (1) Jun 06, 2012
If even a small fraction of the effort expended on boosting horsepower in engines over the last two decades had been devoted to improving mileage, the U.S. would be exporting oil today.


Most of the time those two are the same goal. The powerful engines are typically the most efficient ones as well, because if you improve the efficiency by 1%-point, you get more power out of the same cylinder displacement.

It's just that people have a choice of comfort and safety over economy. The only way you'll actually save any fuel is by driving a smaller, lighter, simpler, slower car because it just takes that much energy to split the wind at speed.
Doc_aymz
5 / 5 (1) Jun 06, 2012
If even a small fraction of the effort expended on boosting horsepower in engines over the last two decades had been devoted to improving mileage, the U.S. would be exporting oil today.


This is precisely what they are doing. Basically cars use heat engines, everything you can do to produce the largest difference in temperature or increase the amount you can burn the more power you can get out of a fixed size engine. So by controlling the combustion process more closely you can get more power because its more efficient, at a fixed speed you'll use less fuel with this efficiency. There have been lots of ill-conceived plans to reduce emissions and they all increase fuel burn, catalytic converters, EGR and diesel particulate filters all mess up the fuel economy particularly when they are not working properly.
Vendicar_Decarian
not rated yet Jun 06, 2012
I find it surprising to see how much Americans are slaves to fuel prices.
Terriva
not rated yet Jun 06, 2012
It shouldn't be surprising for those, who know how cheap the fuel was in the USA. http://www.thepri...hart.gif
Eikka
not rated yet Jun 12, 2012
I find it surprising to see how much Americans are slaves to fuel prices.


As if you aren't. Imagine what happens when the price of fuel doubles to the guy who hauls stuff to the supermarket you visit every other day.

You're just a typical "city green", who can boast about cycling to work and buying organic greens from the corner shop, and bragging about your low CO2 footprint, because other people have done the dirty work and spent the gasoline for you.