Truck owners and manufacturers share responsibility for compliance with the new limits on carbon dioxide emissions and fuel economy, although the initial burden falls on the original equipment manufacturers.

Comments by a builder representative at the Technology & Maintenance Council’s meeting in Pittsburgh last September, sparked angst among fleet managers about how the rule will be enforced.

The general understanding has been that truck and engine builders, rather than owners, will be responsible for obeying the Environmental Protection Agency and National Highway Traffic Safety Administration regulations that went into effect Jan. 1. These rules limit carbon dioxide and require higher fuel economy for commercial trucks (see cover article).

“The agency’s intent was to direct enforcement against the OEMs,” said Glen Kedzie, vice president and energy and environmental affairs counsel at the American Trucking Associations.

“Once equipment enters the hands of fleet purchasers, that’s where the matter of enforcement enters a gray area, given what happens during the useful life of that vehicle once it leaves the control of the OEMs. I don’t believe enforcement will ensue against fleets once they take delivery of new equipment.”

But Zach Slaton, a principal engineer at Kenworth, told the TMC audience that the greenhouse gas regs also place responsibility on owners, the same as is now the case with emissions limits on diesel exhaust.

Fleets must maintain their trucks as built for minimum “useful life” periods, which is 435,000 miles for Class 8 trucks and 135,000 for medium-duty, he said.

Later, he said he was speaking with guidance from Dan Kieffer, director of emissions compliance for Paccar, the corporate parent of Kenworth and Peterbilt.

Kieffer confirmed his reading of the emissions regulations and cited a key paragraph: “Engine and vehicle manufacturers, as well as owners and operators of vehicles subject to the requirements of this part, and all other persons, must observe the provisions of this part, [and] the provisions of the Clean Air Act…” That is paragraph (a) of 1037.601 in the regulations, he said.

That means owners can’t alter anything connected with GHGs or fuel economy unless it’s justified by a change of duties or locales. Affected components will include aerodynamic fairings, fuel-efficient tires and speed-limiting parameters set in engines’ electronic control modules.

If an ECM’s speed limiter were set at 65 mph, no one could legally set it higher during the useful-life period, Slayton said.

Aero fairings must be kept on the vehicle and maintained so they work as designed. And low-rolling-resistance tires must be replaced by new or retreaded tires that also offer low rolling resistance. This led to a question from an exasperated fleet manager.

“What happens if my truck blows a tire on the way to California, and the service truck comes out and replaces it with something that’s not the same brand and type as the original?” asked Tom Wildish, director of maintenance at Freymiller Trucking in Oklahoma City. “Is an inspector later going to see that the truck has nine tires of one kind and the 10th tire is different, and give me a citation?”

HDT put the question to EPA and learned that the answer is in the owner’s manual. Here’s what the agency said:

“In terms of compliance, the primary guidance to the vehicle owners and operators is through maintenance instructions in the owner’s manual that the vehicle manufacturer provides to their customer.

“The manufacturer must provide instructions to the vehicle owner regarding maintaining the vehicle such that it complies with GHG regulations.

“These instructions are included in the owner’s manual and cover issues such as how to replace the original tires with tires that have as good or better rolling resistance characteristics and the proper maintenance of any devices installed on the vehicle that control GHG emissions.

“During the certification process the manufacturer submits their draft maintenance instructions to EPA for review and approval.”

EPA cited section 1037.655 of the Clean Air Act, which specifies the modifications that can and cannot be made during the life of the vehicle.