"E.P.A. Proposal Will Put Bigger Trucks on a Fuel Diet"

"ANN ARBOR, Mich. — Inside the National Vehicle and Fuel Emissions Laboratory here, a mammoth contraption, with steel rollers, advanced electronics and exhaust tubes, is nearing completion.

The project — an enormous “truck treadmill” — is the new centerpiece of the Environmental Protection Agency’s complex. One of the largest vehicle testing centers in the world, the truck lab will play a crucial role in shaping and enforcing a major new environmental mandate by the Obama administration that could dramatically transform America’s trucking industry.

This week, the E.P.A. is expected to propose regulations to cut greenhouse gas emissions from heavy-duty trucks, requiring that their fuel economy increase up to 40 percent by 2027, compared with levels in 2010, according to people briefed on the proposal. A tractor-trailer now averages five to six miles a gallon of diesel. The new regulations would seek to raise that average to as much as nine miles a gallon. A truck’s emissions can vary greatly, depending on how much it is carrying."

Aaron M. Kessler and Coral Davenport report for the New York Times May 30, 2015.