President Obama followed up on a pledge made last month during his State of the Union address in directing the EPA and NHTSA to issue a Notice of Proposed Rulemaking within the next year to evolve the first-ever, fuel-efficiency standards for model-year 2014 through 2018 medium- and heavy-duty vehicles that were finalized in September 2011.
The NPRM would support the adoption of new fuel-efficient technologies specifically on trucks and semi-trailers, but with an impact on school buses as well. The technologies aim to increase engine and powertrain efficiency, vehicle aerodynamics and weight reduction, improved tire rolling resistance, hybridization, automatic engine shutdown, and to improve accessories such as water pumps, fans, auxiliary power units and air conditioning.
"Our customers continue to look for every percent of fuel economy improvement, and that makes finding new solutions an ongoing priority for us at Navistar. We look forward to continuing our collaboration with EPA and NHTSA on this next phase of reducing greenhouse gas emissions," said Denny Mooney, group vice president of global product development at Navistar, the parent company of IC Bus.
The Diesel Technology Forum said the latest standard would also mean it would take only 60 new clean diesel trucks to produce the same level of emissions as those manufactured in 1988. Executive Director Allan Schaeffer added that nearly a third of the 8.8 million heavy-duty trucks in the U.S. meet first-generation clean diesel standards for model-year 2007 engines. Nearly another 15 percent meet the more stringent 2010 standards.
"Today's announcement sets up the next challenge for clean diesel technology to further improve fuel efficiency and reduce greenhouse gas emissions from commercial vehicles, including medium and heavy duty trucks, and buses," he said. "Engine and vehicle makers have all met the first set of Phase I standards for higher fuel efficiency in the current 2014 products that are now certified and for sale. Driven by customer's fuel efficiency demands, OEMs made improvements, which enabled them to meet requirements of Phase 1."
Schaeffer also said the national fleet of clean diesel trucks reduced emissions of NOx by one million tons and reduced particulate matter by 27,000 tons in 2012. This is the same amount of NOx reduction that would result from removing 87 million light-duty cars and trucks from the road for one year, and the same amount of particulate matter reduction as removing 225 million cars and trucks for one year.
"As the fleet of older Class 3-8 medium- and heavy-duty trucks are replaced each year with new clean diesel trucks, these emissions benefits will continue to increase, while fuel consumption decreases," Schaeffer concluded.
More than 90 percent of heavy-duty trucks in the U.S., and about 99 percent of school buses, are diesel powered. According to DTF, nitrogen oxides emissions from heavy-duty diesel trucks and buses have been reduced by 99 percent, and particulate matter emissions are down by 98 percent.