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Improving the fuel economy of heavy vehicles


March 31, 2010

A new report has made suggestion as to how fuel consumption of medium- and heavy-duty vehicles such as this can be improved

A new report has made suggestion as to how fuel consumption of medium- and heavy-duty vehicles such as this can be improved

While there are fuel consumption standards for passenger cars, there is no such regulation of medium- and heavy-duty vehicles in the U.S. With such vehicles accounting for about 26 percent of the transportation fuel used in the U.S. regulators are looking to establish fuel economy standards for these vehicles in the next few years. Now a new U.S. report has been released recommending the best ways to measure and regulate fuel economy for these vehicles, and assess technologies that could improve it. Amongst its findings, the report says that some vehicles could cut their fuel use by about 50 percent through the use of a combination of technologies.

The congressionally mandated report was put together by the National Research Council (NRC) at the request of the National Highway Traffic Safety Administration (NHTSA). It was in response to legislation passed in Congress in 2007 requiring the U.S. Department of Transportation to establish fuel economy standards for medium- and heavy-duty vehicles for the first time in history.

The committee estimated the improvements that various technologies could achieve over the next decade in seven vehicle types. The report found that:

  • using advanced diesel engines in tractor-trailers could lower their fuel consumption by up to 20 percent by 2020, and improved aerodynamics could yield an 11 percent reduction;
  • hybrid powertrains could lower the fuel consumption of vehicles that stop frequently, such as garbage trucks and transit buses, by as much 35 percent in the same time frame;
  • while the cost of making these improvements would be passed on to vehicle purchasers, the report notes that many of these suites of technologies would pay for themselves even at today's energy prices, under the committee's assumptions;
  • using a combination of technologies tractor-trailers could cut their fuel use by about 50 percent by 2020 for about US$84,600 per truck, which would be cost-effective over ten years with gas prices of at least US$1.10 per gallon;
  • fuel use of motor coaches could be lowered by 32 percent for an estimated US$36,350 per bus, which would be cost-effective if the price of fuel is US$1.70 per gallon or higher;
  • for other vehicle classes, the financial investments in making improvements would be cost-effective at higher prices of fuel;
  • the NHTSA should regulate the final-stage vehicle manufacturers rather than component makers, as the former has the greatest control over the vehicle's design;
  • the adoption of nontechnical methods to lower fuel consumption, such as providing incentives to train vehicle operators in efficient driving techniques, could result in fuel savings of anywhere from 2 percent to 17 percent.

Because the miles-per-gallon measure used to regulate the fuel economy of passenger cars is not appropriate for medium- and heavy-duty vehicles, which are designed above all to carry loads efficiently, the report suggested setting fuel consumption standards based on a measure that accounts for the amount of freight or passengers carried by the vehicles.

Instead, any regulation of medium- and heavy-duty vehicles should use a load-specific fuel consumption (LSFC) metric that reflects the efficiency with which a vehicle moves goods or passengers, such as gallons per ton-mile, a unit that reflects the amount of fuel a vehicle would use to carry a ton of goods one mile.

While regulating medium- and heavy-duty vehicles will be more complicated than it is for passenger cars because of the variety of vehicles and their differing tasks and terrains, the barriers are not insurmountable, the report says. Japan regulates the fuel economy of these vehicles, and both the European Union and the state of California are developing standards.

However, one way to avoid the complexity of regulating different types of vehicles suggested by the report would be to impose a fuel tax, which would induce firms to optimize the fuel-efficiency of their operations. The report urges Congress to consider this approach. Another alternative approach - applying a cap-and-trade system to trucking companies similar to the one that Congress is considering as a way to lower CO2 emissions - would similarly provide these companies with an incentive to adopt fuel-saving technologies and operational methods.

The report is intended to influence the choices that will be made over the course of the next few years in establishing the regulatory design for medium- and heavy-duty vehicle fuel consumption standards for the next several decades.

Copies of the full report, “Technologies and Approaches to Reducing the fuel Consumption of Medium and Heavy-Duty Vehicles,” are available from the National Academies Press.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Now there\'s a surprise. We can regulate by adding MORE taxes onto the cost of fuel. NO, NO, NO. no new taxes!!!!! People have got to STOP buying into the approach of controlling something by taxing it.

Rick Voshall

There\'s more than enough taxes already - on everything. Too much of it just gets wasted because it\'s \"easy come easy go\" money. No new taxes on anything. Period.

How about setting a reduction target for new trucks to meet such as reducing fuel consumption by 2% per year for the next 15 years using 2010 fuel consumption as a baseline.

Just make that the law so any truck maker who wants sell trucks has to meet it or he can\'t sell trucks. If a truck maker reduces fuel consumption by 10% in year one he will be way ahead of the pack and will be eager to reduce even more in year two to keep ahead of competitors.

Truck buyers will buy the new trucks over time to remain competitive. Truck makers with the lowest fuel consumption will sell the most trucks.


YES! YES! YES! We need taxes to encourage people to change their behavior. Fuel economy on large trucks has been discussed and researched for a long time, but never implemented because there was no incentive. It NEEDS to be regulated and instead of adding a government department, we can just hike the price of fuel, something that should have been done long ago. Only THEN will these types of improvements finally be made to trucks. The general tax fund pays for environmental clean up now. The causes of pollution and inefficiency should be directly charged for the pollution they cause to 1) reduce the pollution, and 2) to pay for cleaning up the mess they already made. Same with coal and oil. We will have to spend TRILLIONS in the future because we failed to act yesterday. A fuel, oil, and coal tax is the easiest way and will NOT kill jobs if it is implemeted slowly and progressively, which should have been done over the last 30 years. Fighting it now just puts us further behind. Encouraging efficiency and new technology will actually create new jobs and make America more competitive. Don\'t listen to the lies of the coal and oil industry lobby! Europe has high fuel taxes and many European countries are better off than we are.

Mark in MI

And yet again they miss the target. While they might be able to fractionally improve fuel consumption by tweaking the engine they could and would do far more if they did something about the aerodynamics of the vehicle. They are driving big 18 wheel bircks around which is not exactly the best shape to slip through the air. Don\'t think it matters much then consider than on a small fuel effiecient car a rear view mirror (the one on the outside) can account for 25% of the total drag. Then look at one of these with boxy shapes and things stuck on all over and you can see there is a lot of improvment to be had. The turck and trailers both need work before this would do anything.


In 1979 a group of Minnesota college students built a car that was able to get 79 MPG and cruise at 60 MPH, all with off the shelf components, no electronics. The article was in The Mother Earth News magazine and is in their online archive.

Facebook User

@Robo, your proposal penalises the most efficient truck makers. @Wragie, prescribing a solution should be a last resort. It removes the incentive to develop alternative technologies. If you need to force people to do something it shows a systemic failure. Incentivisation is far better. Fuel tax can be revenue neutral (swap it for some other tax) if that\'s desirable or necessary for economic reasons. User/polluter pays in true capitalist style.


There is huge incentive for better fuel economy without the need for raising taxes. Lower operating costs alone for owner/drivers as well as fleets can and will drive the market for innovation. Less operating cost will mean less shipping costs as well, further stimulating the economy. On a smaller, yet equally important, scale is the need for more efficient RV\'s. Just look at the number of large diesel pusher motor coaches around. For us, 20% better fuel economy is enough to make the trip from Florida to our farms in Ohio on less than one tank instead of stopping for fuel. Not only a matter of convenience but, over the life of the coach, considerable savings as well. Innovative strides towards fuel efficient recreational vehicles will also provide stimulus to the ailing RV industry and help create thousands of jobs. This is merely the tip of the iceberg in terms of goods, services and many other \"diesel driven\" technologies that support our economy. (not to mention agriculture)

Bruce Williams

Using Eaton\'s hybrid assist would go a long way to improving the mileage-along the lines of over 40 percent for large vehicles that stop and go a lot-hydraulic accumulators! Add solar to the rooftops for an additional battery for the extras the drivers need when parked. Add regenerative shocks from Electric Truck to capture all that wasted kinetic energy in the bouncing we get from every road. Another 7-9 percent savings. All in all it would not take ten years to recover these investments more like 4 years. Lighten the steel-use more basalt and carbon fiber. I wish these trucking companies would get it. Better aerodynamics for sure. Why does it take them until 2020 to get to this? The bureaucracy gets in it\'s own way time and time again-I wish they would realize we the planet do not have that much time to dawdle-get freeking on with it-that\'s ten years away and the technology is here NOW-DUH

Nick Gencarelle

I agree wholeheartedly - no new taxes. While it MIGHT provide some incentive for investing in better fuel economy it is also likely that the increased expense just be passed on and we the consumers will really be the ones footing the bill. No thank you.

The article does mention an 11% savings due to aerodynamics but that seems based on refining current designs rather than a ground up redesign. Heck, this article claims 7.5% reduction in fuel consumption by just adding a boat tail. I am sure this could be modified to fold up and swing relatively flat against the side of the trailer when not in use. http://www.gizmag.com/truck-boat-tail/13283/

The main issue is the trucking industry\'s resistance to change. I worked for a trucking company for a few years it is still a macho / good ol\' boy mentality industry. There are already a lot of bolt on products available. http://www.heavydutytrucking.com/2006/03/072a0603.asp


What we really need is a real alternative to carbon fuels. Please check this out:


Ray Solar

Wait! Our products ALREADY give a 35%-50% boost in mileage to the trucking industry! We are in the process of getting DOT and EPA certification. And instead of $85,000, our units range from $2500-3500 and are ready to install. One of our trucks, a 1995 Freightliner, recently reported his mileage going from 6 mpg to 8.75 mpg using one of our CAR units. You can see the article here: http://hhokitsdirect.com/articles/hho-kits/1995-freightliner-big-rig-goes-from-6-mpg-to-875-mpg-using-our-hho-generator.html

Our company is built on Transitional Technologies that are ready NOW, not in 3,5,or10 years. We are also in talks with a major truck mfg. who is interested in collaborating to design an OEM product based on our unique Hybrid Cell design.

Facebook User

Some 10 years ago Kenworth/Peterbuilt were testing a Tractor Trailer set-up that had a GM 3.8 V6 that ran a generator that powered the electric motors . No Diesel Fuel and a Gas V6 that ran at a constant RPM . The Vehical had better pickup speed then it\'s diesel brother . Used considerably less fuel . This without changing the outside apperance , changing that would no dought help . They had two of these rigs on the road , hauling loads etc . So What Happened to them ?

Econo Guy
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