New Report: Congress Should Boost Truck Efficiency by Raising Gas Tax

As the federal government moves forward on a mandate to set stronger fuel-efficiency rules for trucks and buses, a new report from an independent scientific body is urging lawmakers to take another approach: raise fuel taxes.

The 2007 federal energy law aimed to set new fuel-efficiency rules for trucks as well as buses. (Photo: TTI)

The National Research Council (NRC), which often advises Congress and the executive branch on environmental and transportation issues, yesterday reported on several strategies to decrease emissions from heavy-duty vehicles.

Several technological improvements scored high on the NRC's fuel-savings scale. Adding hybrid powertrains to big rigs, for example, could cut fuel use by up to 50 percent over five years, and phasing out gas engines in favor of diesel-powered ones could achieve up to 24 percent in fuel savings.

But the NRC's most surprising advice came on the topic of higher fuel taxes, which the report described as an efficient way to correct the "social inefficiency" that results when private businesses decline to cut emissions "since the private return is too low." The report also projected that higher fuel taxes would encourage freight-carrying firms to make wider use of other gas-saving tactics.

"Although the committee recognizes the political difficulty with increasing fuel taxes, it strongly recommends that Congress consider fuel taxes as an alternative to mandating fuel efficiency standards for medium- and heavy-duty trucks," the NRC authors wrote.

Another benefit of raising fuel taxes to spur emissions cuts, according to the report, is the prospect of more immediate economic and environmental benefits.

"[A] tax affects the utilization of vehicles already on the road, while fuel consumption standards typically affect only new vehicles and can be implemented only slowly over time as the vehicle fleet transitions to the more fuel-efficient vehicles," the NRC authors wrote.

The report was produced in response to Congress' 2007 energy bill. That legislation raised fuel-efficiency standards for cars to 35 miles per gallon (mpg) by 2020 -- a target that the Obama administration has upped to 35.5 mpg by 2016 -- and called for new federal fuel standards for heavy vehicles such as trucks and buses.

However, academic researchers have criticized the traditional mpg metric for failing to fully reflect the regulatory benefits of reining in emissions at the least fuel-efficient end of the scale. The NRC report takes the issue a step further by counseling regulators to abandon mpg entirely for trucks and buses, instead using a load-specific metric that rewards trucks stocked fully with freight.

Miles per gallon "is not the appropriate measure for [medium and heavy vehicles], since these vehicles are designed to carry loads in an efficient and timely manner," the NRC authors wrote. "A partially loaded tractor trailer would consume less fuel per mile than a fully loaded truck, but this would not be an accurate measure of the fuel efficiency of moving goods."