Earlier in February, the American Chemistry Council (ACC, Washington, DC) submitted written comments on a federal proposal to increase fuel efficiency and reduce greenhouse gas emissions in passenger automobiles and light trucks, showing how plastics could contribute to improving fuel economy standards proposed for 2017 and later model year light-duty vehicles.
The National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) have chosen to "provide an incentive to use lightweight materials and structures," rather than "reductions in size," by adopting a footprint approach to emission reductions, according to the ACC comments, which also support the agencies' approach to consider only vehicle mass reduction that will not adversely affect overall fleet safety.
In addition to lightweighting, plastics and related materials will also contribute to fuel efficiency and emission reductions through more aerodynamic shaping and parts integration according to the ACC. "About 60 percent of engine power at highway cruising speed is used to overcome air resistance. As a result, improved aerodynamics translates into substantial improvements in fuel efficiency and emissions, even with vehicle size held constant," notes the ACC comments. "Injection-molded plastics allow for aerodynamic styling and parts integration not possible with metal or glass. Drag coefficients for present-day vehicles range between 0.30 and 0.35, but an additional 25 percent reduction in drag has been predicted in coming years."