Environmental regulators should develop a separate standard for natural gas vehicles when they implement the second phase of fuel-efficiency standards for heavy-duty trucks, according to a study released April 3 by the National Research Council of the National Academy of Sciences.
The new report offers guidance for the Phase II rule under development, directed at technologies and programs in the post-2018 time frame.
Those standards — announced in February by President Obama — are a follow-up to a 2014 regulation requiring carbon dioxide emissions and fuel economy improvements in heavy- and medium-duty trucks fueled by diesel or natural gas.
Obama directed a new fuel rule to be developed by March 2016, which could take effect by 2020.
Expanded use of natural gas as a transportation fuel — along with greater use of aerodynamic devices on trailers — are among NRC’s recommended strategies for reducing fuel consumption by tractor-trailers, buses, commercial vehicles, trucks and other medium- and heavy-duty vehicles, the study said.
The report follows a 2010 NRC report whose findings and recommendations informed the Phase I rule on fuel consumption and greenhouse gas emissions of medium- and heavy-duty vehicles issued jointly by the National Highway Traffic Safety Administration and U.S. Environmental Protection Agency.
EPA wants to reduce GHG emissions — primarily CO2 — while NHTSA is concerned with boosting miles per gallon.
The report also recommended that federal agencies adopt a regulation requiring that all new 53-foot or longer dry-van and refrigerated-van trailers meet performance standards that will reduce fuel consumption and CO2 emissions.