The Benefits of Heavy-Duty Vehicle Standards

Ask a Scientist - March 2015

This month, Don Anair, deputy director of our Clean Vehicles Program, sits down with Elliott Negin, director of news and commentary, to answer questions about the benefits of new fuel economy standards for heavy duty vehicles.

In 2011, the Obama administration introduced the first-ever fuel economy and carbon emission standards for heavy-duty vehicles, from delivery vans to buses to tractor-trailers. The original standards cover new trucks sold between 2014 and 2018. A follow-on set of standards, to be proposed this year, will extend the program beyond 2018 and deliver even greater oil and emissions savings. UCS has been promoting comprehensive heavy-duty vehicle standards for some time, publishing analyses and submitting testimony to relevant federal agencies.

A couple of years ago, UCS launched a campaign to cut U.S. oil use in half by 2035. How much of an impact do heavy-duty vehicles have on U.S. consumption, and what can the new standards do to reduce their share?

Trucks and buses make up a pretty small percentage of vehicles on American roads—only 7 percent—but they’re responsible for more than a quarter of the fuel vehicles consume every year, so whatever we can do to improve their fuel economy will go a long way. Moving forward with another round of strong standards for medium- and heavy-duty trucks could cut the average fuel consumption of new trucks by 40 percent in 2025 compared to 2010 models. With that level of improvement, we would save 500 million barrels of oil (pdf) in 2030 alone. It will also keep nearly 270 million metric tons of global warming emissions out of the atmosphere that year.

Tell us a bit about how these new heavy-duty vehicles are going to get better fuel economy.

There are a number of technologies that will get us there. Many of them are already available, but some are still being developed.

One of the biggest obstacles is engine inefficiency. Most tractor-trailer engines on the road today use less than half the energy in diesel fuel for power. The rest of it is wasted, much of it as heat in the exhaust. One of the Department of Energy’s SuperTruck program’s goals is to develop technologies that convert some of this heat into usable electrical or mechanical energy to help operate the vehicle more efficiently. Truck manufacturers Cummins and Peterbilt have jointly designed a tractor-trailer prototype that utilizes this technology, along with others, to get more than 10 miles per gallon, a significant increase from the 5.8 mpg typical of tractor trailers. 

Truck design also is a key issue. Poor aerodynamic tractor-trailer design, for example, can account for 15 to 22 percent of total energy loss on the highway. The existing heavy-duty vehicle standards have prompted manufacturers to continue to optimize the shape of tractors to reduce drag. However, the box-shaped trailers not covered by the first round of standards offer a significant opportunity for additional fuel savings. Applying a combination of aerodynamic devices to trailers alone could cut fuel consumption by as much as 12 percent.

Hybrid diesel-electric trucks also can help cut fuel use and emissions. Several truck manufacturers are now selling hybrid models, and thousands of hybrid systems are already in vehicles ranging from delivery trucks to metro and school buses. A National Academy of Sciences review found that current hybrid truck technologies could cut fuel use by as much as 50 percent depending on the truck type and specific technology used.

There’s more, but that gives you an idea of the possibilities. Anyone interested in finding out more should check out our “Big Rigs, Big Oil Savings” (pdf) fact sheet. 

Sounds good, but won’t those technological improvements drive up the cost of trucks?

There’s an old saying: “You have to spend money to make money.” In this case, you have to spend money to save money. Let me give you an example. A new tractor-trailer with an advanced engine and transmission, a new axle design, and better, aerodynamic design would cost about $32,000 more than a conventional tractor-trailer. But those improvements would save about $30,000 in annual fuel costs. So the owner of that spanking brand new truck would get back that initial investment in only 13 months. That’s a good deal for not only truck owners, but public health, the environment and the climate, too. How could you argue with that?

Don AnairDon Anair is an engineer in the California office of the Union of Concerned Scientists' (UCS) Clean Vehicles Program working on state and national transportation, air quality, and global warming policy. Before Mr. Anair came to UCS, he worked as a system design engineer for Applied Signal Technology where he received a patent for a new satellite communications product. Mr. Anair holds a bachelor's and master's degrees in electrical engineering from Cornell University.