MC CLEAN, Va. An examination of the impact of the 2004-10 federal emissions standards on commercial vehicles indicates the U.S. Environmental Protection Agency badly underestimated the cost of the rules.

The study by the National Automobile Dealers Association and the American Truck Dealers says the USEPA emissions rules for model-year 2004 to 2010 resulted in substantially higher prices for commercial vehicles, lower sales and delay of environmental benefits.

The study, "A Look Back at EPAs Cost and Other Impact Projections for (Model Year) 2004-2010 Heavy-Duty Truck Emissions Standards," said there has been little examination of EPAs cost predictions, compared with the actual cost of meeting its motor vehicle emissions mandates.

The report showed that EPAs original estimate of how much the new rules would cost vehicle makers and their customers was off by an average of two to five times, Doug Greenhaus, chief regulatory counsel for environment, health and safety issues for NADA and its ATD division, said in a conference call after the study was released.

For example, on average, the actual cost increases for model-year 2010-compliant medium-heavy trucks were more than twice what EPA projected, the study said.

The agency had estimated that manufacturer surcharges for the 2010 model year trucks would average $2,737, but ATD/NADA noted that the actual charges ranged from $3,868 to $7,300, depending on manufacturer.

EPA 2004-10 rules caused heavy-duty truck prices to spike by $21,000 over what tractors cost in 2000, the study said. That added cost was for regulatory compliance, although EPA had said those costs would be only $5,000, said Esteban Plaza-Jennings, the studys primary author.

"To work, fuel-economy improvements must be affordable. You cant dictate what customers will buy. If our customers do not want to purchase these vehicles, we all lose," said David Westcott, NADAs vice chairman and president of Westcott Automotive in Burlington, N.C.

The ATD/NADA report looked at the 2004-2010 medium- and heavy-duty truck emissions mandates. "It shows what can happen when a regulatory proposal - based on far-in-advance predictions - seeks to set mandates far in the future," the study said.

The primary goal of the EPA mandates was to reduce nitrogen oxides and particulate emissions, noted Dick Witcher, ATD chairman and CEO of Minuteman Trucks in Walpole, Mass.

But Witcher warned that setting emissions standards, whether theyre large or small, is dangerous for any regulatory agency because the variables are too difficult to predict, at least with any accuracy.

"The risks are too high, and the unintended consequences are too great," Witcher said. "Any goals should be set in smaller increments of time."

ATD and NADA said the lessons learned from this study now apply to the proposed model years 2017-2025 fuel-economy regulations for light and heavy vehicles, including over-the-road buses.

"That rulemaking, combined with previous Obama administration fuel economy mandates, will raise the average price of a vehicle by $3,000, according to EPA and National Highway Traffic Safety Administration estimates," the groups said.

"When faced with unreasonable federal regulatory mandates that increase motor vehicle costs, buyers of light-duty vehicles - similar to what commercial truck buyers experienced - will seek out less-expensive alternatives in the marketplace," the study concluded.