Saturday, January 2, 2016

Coffee Brake: U.S. EPA Fuel Economy Trends Report

by Gianni -- Each year since 1975, the U.S. Environmental Protection Agency issues an annual Light-Duty Automotive Technology,Carbon Dioxide Emissions, and Fuel Economy Trends Report.  The report for 2015 has just been issued this month.  The report runs 155 pages and is chock full of interesting trend data on the U.S. car and truck fleet.  You can read the entire PDF of the report here, or if you have a short attention span, I've pulled out a few interesting tidbits for this Coffee Brake, for you, our dear reader.

The report uses data collected from the manufacturers as part of their annual required reporting to the EPA and NHTSA.  It includes alternative fuel vehicles as well as conventionally powered ICE vehicles.  Model year 2014 data in the report is final and MY2015 is preliminary and will be adjusted to final with next years report.  The overall U.S. fleet for MY2014 achieved an fuel economy value of 24.3 miles per gallon, unchanged from MY2013.  MY2015 is predicted to be up slightly to 24.7.  It is interesting to look at the trend chart since 1975.  We achieved large gains in economy back in the 1980's, took a break and then began improving again in the mid-2000's.  Horsepower for MY2014 increased slightly from MY2013 and is back to matching an all-time high of 230 hp registered in 2011.  The trend in hp since '75 is interesting as well, taking a large dip until 1980 and then increasing ever sense.  Vehicle weight is now averaging 4,060 lbs and looking at the trend line, we are back to where we were in 1975.  Starting in 2008, the report began measuring vehicle footprint as expressed in square feet.  For MY2014 we are at an all-time high since the measure started, at 49.7 square feet, up 1.2% over MY2013.

Conventional wisdom in car-geek circles is that pickups are taking over and no one buys cars anymore.  If you look at the trends in production share, you see that cars have been decreasing their 80.6% share since 1975, but pickups have pretty much held the same share over the 40 year period (13.1% share in 1975 and 13.4 preliminary share in 2015).  The rise of Minivans and then truck-based SUV's have been driving the share of cars down down to 49.2% in MY2014.  Minivans are now trending down, much to the consternation of those that know better than you what you should drive, and car-based SUV's are now increasing their share.

With the rise of horsepower, obviously 0-60 times have fallen dramatically.  The predicted  MY2015 number of 8.2 seconds is an all-time high. 

Technology, especially the trends in multi-valve engines with variable valve timing along with 6 speed or greater automatic transmissions is the main driver of the increasing trends of fuel economy along with increasing horsepower, vehicle size, weight and dropping acceleration times.  This truly is the golden age.

The report also breaks down the fuel economy numbers by manufacturer.  For the last two years, plucky Mazda has come out on top, besting Subaru by a respectable margin both years.  This is pretty cool, not just because I'm a Mazda Fanboi, but because Mazda doesn't have any diesels, hybrids, electrics or even CVT's in its line-up.  Skyactive is more than marketing.  On the other end, the domestics fall to the bottom with their greater mix of large vehicles.   FCA has a average of 21.8 mpg for MY2015, compared to Mazda's 30.1 mpg.  Hyundai/KIA are back in the report after settling their clean air act violations and VW has been kicked out until Diesel-gate is resolved.  Unfortunately for golf-cart enthusiasts, Tesla isn't included.  Would it be rated as 0 mpg or infinite mpg or miles per ton of coal burnt?

Drilling down on the key metrics that have some bearing on fuel economy by Manufacturer you can see how Mazda and Subaru sell smaller, lighter, more modestly powered vehicles as compared to FCA.  I guess Sergio isn't selling enough 500's to offset the trucks and SUV's.

This is just a small scratching of the surface of the report.  If you have some time, take a look at it or at least scroll thru the data visualizations and post some of your observations in the comments.

Gianni is DT's Pacific Northwest Correspondent.  He's a big data geek.


  1. Gianni, thanks for saving me from having to read 155 pages. Didn't realize the government collected this much data on cars/trucks. I would have thought vehicle weight would have increased more but maybe some of that has been offset with lighter materials. Probably would have been more fuel economy gains if everybody wasn't chasing horsepower.

  2. Great numbers...I knew I liked Mazdas attitude toward efficiency and here it is to see!
    Good stuff and I hope we shop chasing the race from light to light numbers.

  3. Nice post, thanks Gianni!

  4. Not to take anything away from Mazda's engineers and their SkyActive technology but they average among the lightest vehicles around which sure helps in those MPG figures.


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