Rush Warns EPA’s 2027 Rule Could Take Longer Than Expected

Waiting on EPA ’27 rule, Rush says final decision may be delayed

The trucking industry is still waiting for the Environmental Protection Agency to finalize proposed changes to its 2027 heavy-duty nitrogen oxide rules, and Rush Enterprises CEO William “Rusty” Rush said the decision may not arrive as soon as many in the industry had expected.

Speaking during Rush Enterprises’ earnings call with analysts Wednesday, Rush said he was hearing that the agency would not issue the final rule in November. He predicted that a final decision could come in January or February, even though the underlying 2027 emissions requirements are scheduled to take effect Jan. 1, 2027.

“There have been some things that have gone in the EPA that are going to delay it,” Rush said, without providing specifics. He added that the industry might instead be asked to work from a draft version of the rule while the remaining issues are resolved.

The uncertainty matters to truck buyers, fleets and drivers because manufacturers must decide how and when to introduce engines that meet the new requirements. Rush Truck Centers, one of the country’s largest truck retailers, will be among the dealers selling and supporting those vehicles.

What EPA ’27 changes

The term “EPA ’27” refers to the model year in which the tighter standards are scheduled to apply. The EPA finalized the core heavy-duty emissions rule in December 2022. It requires diesel engines built for model year 2027 and later to reduce nitrogen oxide, or NOx, emissions by roughly 80% to 90% compared with current limits.

One of the key limits is 0.035 grams per brake horsepower-hour under normal operating conditions, compared with the current 0.2 grams per brake horsepower-hour standard. That represents an 82.5% reduction.

The rule also covers emissions performance during low-load operation, idling and cold starts. It increases durability expectations for emissions equipment and extends the period over which engines must remain compliant. The emissions useful-life requirement is scheduled to increase from 435,000 miles to 650,000 miles under the original rule.

Those changes are expected to require more advanced after-treatment systems, additional monitoring and greater long-term durability. Manufacturers have been developing new engine and emissions technologies to meet the standards, but the proposed amendments could change the timing and cost of the transition.

Noncompliance penalties are central to the debate

The July amendments proposed allowing manufacturers to use noncompliance penalties, or NCPs, during the early years of the new standards. Under that approach, an engine that does not initially meet the full standard could be certified if its manufacturer pays a penalty based on how far the engine is from compliance.

The proposed NCP program would apply to model years 2027 through 2029, with penalties increasing over time. The closer an engine is to the required emissions level, the lower the penalty would be. The provision is intended to give manufacturers time to validate new technology while allowing trucks to remain available for purchase.

Rush said the provision could allow fleets to gain experience with the new engines before manufacturers move entirely to fully compliant designs.

“Most folks want to run this stuff for over a year before they roll it into their fleets, because we’ve seen through history that new technology does not always run right out of the gate,” Rush said.

He cited the rollout of diesel exhaust fluid systems in 2010 as an example of new emissions technology creating service problems during its early deployment. From a fleet perspective, a phased introduction could provide more time to evaluate reliability, maintenance needs and real-world performance.

The American Trucking Associations and several engine manufacturers have supported retaining NCPs in the final rule. The ATA has said the penalties could help prevent engine shortages and support a more orderly transition while maintaining pressure on manufacturers to reach the stricter limits.

PACCAR also told the EPA that NCPs would help manufacturers launch products that have been fully tested rather than rush unvalidated technology into the market. Cummins, meanwhile, urged the agency to finalize amendments involving NCPs, emissions warranties and useful-life requirements quickly so manufacturers can certify 2027 engines under the revised provisions.

Warranty and useful-life rules add uncertainty

The EPA’s proposed amendments also address warranty and useful-life requirements, both of which have financial consequences for manufacturers and customers.

Under the original rule, longer emissions warranties would increase manufacturers’ responsibility for emissions-related components over the engine’s required useful life. The proposed changes would keep current warranty requirements in place rather than immediately imposing the longer obligations. The amendments also would delay tighter useful-life requirements until 2030, according to information provided by Rush Truck Centers.

Those provisions are important to fleets because emissions-system repairs can be costly, and warranty coverage affects how much financial risk an owner carries after a truck enters service. They also influence the purchase price and maintenance planning for new equipment.

Rush said the timing could result in different manufacturers bringing fully compliant engines to market on different schedules if the NCP provisions are adopted.

“Some will come in on January 1. Some may not do it until the following year,” he said. “I don’t believe we’ve had time to truly test these engines.”

EPA says it is reviewing comments

In a statement, an EPA spokesman said the agency understands the need for timely action and regulatory certainty.

“The agency is carefully reviewing the comments received and is working to finalize the rule as expeditiously as possible,” the spokesman said.

The pending decision does not eliminate the core 2027 NOx standards. Instead, it could determine how manufacturers transition to them, including whether they can use temporary NCPs and how warranty, useful-life and related requirements will be applied.

For drivers and fleets, the practical questions are when compliant engines will be available, how reliable the first generation of equipment will be and what the final rules will mean for purchase prices, maintenance and warranty coverage. Until the EPA issues its decision, manufacturers, dealers and customers will continue planning around a 2027 deadline whose implementation details remain unsettled.