ORLANDO — Truck operators and builders are commenting strongly on the proposed Phase 2 Fuel Economy and Greenhouse Gas emissions proposals, and the U.S. Environmental Protection Agency is taking notes and might well make some changes to the lengthy set of rules. That was a takeaway from a Tuesday session at the Technology & Maintenance Council’s fall meeting near Orlando.

Panelists including an EPA regulator, a truck builder, a trailer manufacturer and a big-fleet manager offered insights on the June proposals made jointly by EPA and the National Highway Traffic Safety Administration, as well as experiences dealing with previous EPA rules that have proven troublesome and expensive.

Billed as an “implementation roadmap,” the session saw discussions of what is likely to happen when the rules become final, and indicated that EPA is serious not only about further reducing exhaust emissions but also about boosting vehicle fuel economy. And the agency official’s remarks suggested that it intends to be reasonable about it.

The Phase 2 GHG proposals, as they’re commonly called, will build on the "successful" Phase 1 rules now in effect, said Matthew Spears, executive director of EPA’s Heavy Duty Diesel Program. The upcoming rules will require advanced aerodynamics and combustion technology, and more use of low-rolling-resistance tires and tire-inflation devices.

And EPA and NHTSA will “encourage the development of new technology” to meet fuel economy and emissions-reduction goals, he said. He repeated claims made during announcement in June that investments in equipment will be paid back in as little as two years (for Class 8 tractor trailers in highway service) to six years (for large pickups and cargo vans).

Brian Keek of Con-way Freight countered those rosy forecasts by listing a long, expensive history of defects with EPA-mandated emissions controls on 2002/04, ’07 and ’10 diesels. But he noted that the 2010 engines began getting better fuel economy, which was lost starting with the first changes in ‘02/04, and that diesels built since 2010 seem to be getting more reliable.

Kenworth engineer Jason Johnson acknowledged that that today’s engines run so cleanly that 65 trucks powered by them produce the same amount of emissions as a single 1990-model truck. But he brought up “unknowns” about certain aspects of the Phase 2 rules:

• While California’s highly influential Air Resources Board is “aligned” with the Phase 2 proposals, as Spears said, CARB might again go its own way and make rules stricter;

• There’s a “mismatch” between model years of trucks and engines, which must be resolved;

• The rules are focused on regulating manufacturers, but emissions will be tested by state and local authorities when equipment is in the hands of owners; and

• Technology development to satisfy the rules “is not guaranteed.”

In response to a reporter’s question about the model-year mismatch, meaning trucks enter model years many months before engines, which would lead to manufacturing and enforcement confustion, Spears said EPA is looking at “several approaches” to resolve it.

The reporter also asked if EPA wants to ban glider kits, which are addressed in the proposals. Spears said the agency doesn't want to ban them, but wants to reduce emissions from the older engines used in the kits, and wants high-mileage, glider-kitted road tractors to use diesels meeting current emissions limits. He said low-mileage vocational trucks that produce little pollution, such as concrete mixer chassis, might be left alone.

On the trailer side, Charles Fetz, who directs product development for Great Dane Trailer, said the Phase 2 trailer rules as currently proposed will demand a 6% reduction in greenhouse gases compared to SmartWay Basic performance of 2018; 8% and 10% reductions in ’21 and ’24, respectively, which the rules call Intermediate; and a 12% cut in the Final step in 2027. Advanced aerodynamics and low-rolling-resistance tires with automatic inflation systems are expected to accomplish those improvements.

The comment period for the Phase 2 proposals ends Oct. 1, and Spears said the final rulemaking would be announced the second quarter of next year.