Last week the feds released their final rules for Phase 2 heavy-duty vehicle fuel-efficiency and greenhouse gas standards, which go into effect in 2018 and run through 2027. There’s much to digest from the 1,700-page document, and we’re getting help from truck and trailer builders and interested organizations and are publishing stories elsewhere on TruckingInfo.com.

Trailers, the subject of this weekly blog, have long been regulated for safety. But trailers’ contributions to fuel economy and reduced emissions are new matters for the federal Environmental Protection Agency and the National Highway Traffic Safety Administration, the agencies that jointly researched and wrote the rules. That caught the attention of the International Council on Clean Transportation, a “green” think tank based in San Francisco.

“By far the most significant new addition into the regulation are the trailers hauled by heavy-duty tractor trucks,” wrote Ben Sharpe, a principal researcher at ICCT, in a blog. “Trailers were not included in the [current] Phase 1 rule, and their inclusion in Phase 2 helped to squeeze an extra half a mile per gallon out of tractor-trailers.

“Ok, so what?” he continues. “Well, for the vehicles affected by the regulation, adding an extra 0.5 mpg across the entire tractor-trailer fleet in the U.S. translates to a reduction of about 7 billion gallons of diesel and 100 million metric tons of CO2. That’s roughly the same as taking all of the passenger cars and trucks in California off the road for an entire year! So including trailers in Phase 2 is indeed a big deal.”

What trailer types are affected? As suggested in last year’s Phase 2 proposals, they’re mainly box-type dry and refrigerated vans, Sharpe says. They’ll have to use gap reducers, trailer skirts, boat tail devices and other aero improvers. This can get complex and trailer manufacturers will have to figure out what exactly is required to attain the improved performance demanded by the regs.

Levels of performance, called “bins,” will phase in over the term of the Phase 2 period. As time goes on, higher levels must be attained, requiring more and more sophisticated devices and maybe smoother basic shapes (see illustrations).

Many vocational-type trailers must also make improvements. Sharpe mentions flatbeds, tankers, grain haulers, auto transporters, and container chassis, but there are more types affected. For them it’s simple, if not cheap. They’ll have to use low-rolling-resistance tires and automatic tire-pressure management devices.

As with box trailers, manufacturers will install devices as the rules require. Truck owners and operators will not be responsible for installing them, though they’ll probably have a say in what’s used and might be required to keep everything in good repair.

“Our research in the U.S. and Canada has shown that the cost of trailer fuel-saving technologies has dropped considerably in the past 5-7 years,” Sharpe says. “This has made the economics quite attractive for a number of fleets, even in the absence of regulation, as we’ve seen uptake of these technologies continue to accelerate in recent years.

“With the Phase 2 regulation, trailers in the U.S. become the first in the world to be regulated based on their impact on fuel efficiency and carbon emissions. The rule ensures the accelerated adoption of proven cost-effective efficiency technologies for trailers and also encourages continued innovation in tires, aerodynamics, and weight reduction. …

“Trailers in the U.S. will be leading the world on getting fuel-saving technologies on the road that are a major boon to trucking fleets and society as a whole.”