The feds announced the start of proposed rule-making for the first-ever program that aims to reduce greenhouse gases (GHG) emitted by medium- and heavy-duty trucks and buses, the transportation sector’s second-largest contributor to oil consumption and GHG emissions.
A notice had yet to be filed on the Federal Register as of this report.
School buses fall under the category “vocational vehicles,” for which EPA and NHTSA proposed a standard of metrics of gram per ton-mile to account for heavier loads carried by these vehicles that burn more fuel. The rules are proposed to regulate chassis manufacturers to meet 10 percent additional reductions in emissions levels.
EPA and NHTSA noted that these vocation vehicles undergo complex build processes, with an incomplete chassis often built with an engine and transmission purchased from other manufacturers, then sold to a body manufacturer.
Class 2b through Class 5 light-heavy vehicles can include Type A and Type B school buses ranging from 6,000 pounds to 19,500 pounds GVWR. These vehicles must meet 344g CO2 per ton-mile and a Corporate Average Fuel Economy (CAFE) rating of 33.8 gallons per 1,000 ton-mile for the 2014 through 2018 model years. Meanwhile, Type C conventionals and Type D transit-style buses fall in the category of Class 6 and Class 7 medium-heavy vehicles with GVWRs of 19,500 pounds to 26,000 pounds. These vehicles must meet the standard of 204g CO2 per ton-mile and 20 gallons per 1,000 ton-mile.
Additionally, some Type Ds could fall in the Class 8 heavy-heavy category of 26,000 pounds to 33,000 pounds. Emissions standards for these buses would be reduced to 107g of CO2 per ton-mile with fuel consumption coming in at 10.5 gallons per 1,000 ton-mile.
Both Cummins, Inc. and Navistar, current manufacturers of EPA-compliant school bus diesel engines, said in separate statements that they were both expected to be in compliance soon with the proposed standards.
The proposed rules cover not only engines but also hybrid powertrains and tires, the latter accounting for the second largest contribution of energy losses for vocational vehicles, according to EPA and NHTSA.
EPA is also proposing standards to cap current NO2 and CH4 emissions from engines to keep manufacturers from allowing significant emissions increases in the future.
The joint rulemaking by the EPA and NHTSA was first announced last November following a presidential directive in May 2010. The agencies are drawing from the EPA SmartWay Transport Partnership Program to identify verified technologies and operational approaches in creating the new Heavy-Duty National Program.
To allow manufacturers flexibility in meeting the new standards, the HD National Program allows for engine and vehicle ABT programs that allow for emissions and fuel consumption credits to be averaged, banked or traded within each regulatory subcategory. The proposal does not allow for those credits to be transferred across categories.
According to the feds, transportation accounts for 72 percent of domestic oil usage, with heavy-duty vehicles accounting for 17 percent of that amount. The new standards would reduce GHGs by nearly 250 million metric tons and save approximately 500 million barrels of oil over the life cycles of model-year 2014 to 2018 vehicles, including school buses, which fall in the vocational category of medium- and heavy-duty commercial vehicles.
In all, the combined EPA-NHTSA standards is expected to reduce CO2 emissions from medium- and heavy-duty fleet vehicles by 72 million metric tons by 2030.
EPA and NHTSA said in a statement that the HD National Program would cost the affected industries approximately $7.7 billion while generating $49 billion in societal benefits, namely reduced health care costs and less money paid for fuel. Additionally, EPA and NHTSA said current technologies could result in a payback of one to two years for most vehicles. Lower-mileage vehicles would experience a payback in four to five years.
Editor’s Note: Read a more in-depth report on the GHG emissions and CAFE standards for school buses in the August edition of School Transportation News magazine.
