California’s lead agency for regulating air quality has received the clearance of the U.S. Environmental Protection Agency (EPA) to enforce its regulations requiring certain truck operators to use aerodynamic devices and low-rolling-resistance tires.

In a notice published in the Aug. 7 Federal Register, EPA announced that it had granted the California Air Resources Board’s request for a waiver of preemption under the Clean Air Act.

As a result, CARB is allowed to enforce its heavy-duty (HD) tractor-trailer greenhouse gas (GHG) regulations as they apply to certain vehicles. The affected vehicles are new 2011 through 2013 model year Class 8 tractors equipped with integrated sleeper berths and new 2011 and subsequent model dry-van and refrigerated-van trailers that are pulled by such tractors on California highways.

CARB asked for the waiver in June 2013. Although the HD GHG regs apply to a broader class of vehicles, the California agency specifically limited the scope of its request to just new MY 2011-MY 2013 tractors and MY 2011 and later trailers “that together are considered to operate as an integrated vehicle.”

According to court precedent, opponents of a waiver request by California bear the burden of showing that it should be denied. EPA received comments on the request from the American Trucking Assns., the California Trucking Assn., the Owner-Operator Independent Drivers Association and the California Construction Trucking Assn.

Any petitions for review must be filed by Oct. 6.

Among the questions EPA needed to answer was whether including trailers in the regulations constitutes “standards relating to the control of emissions from new motor vehicles or new motor vehicle engines.” If not, CARB wouldn’t even be preempted from regulating trailers as state law provides for such regulation, EPA said.

EPA concluded that since the tractor and trailer need each other to accomplish their mutual goal of hauling cargo, a tractor-trailer combination meets the definition of a motor vehicle under the law. Also, consistent with EPA’s own regulation of GHG emissions from heavy-duty engines, the agency noted that improvement of trailer aerodynamics and greater efficiency in a trailer’s tires properties will result in GHG emission reductions from the engine, the agency said.

Some comments objected that because California’s regulations focused on GHGs and not oxides of nitrogen (NOx) or particulate matter the rules don’t fall under California’s presumptive authority to address “compelling and extraordinary conditions.” EPA responded, however, that because reducing GHGs would necessarily reduce NOx and particulate matter emissions, the regulations qualified.

Once California’s regulations clear the definition question and the “compelling and extraordinary conditions” test, the only question left is whether the technology is infeasible or cost of compliance excessive. EPA said there was no argument presented on technological grounds, and it declared that commenters had not met their burden of proof of excessive costs – especially since the technologies adopted would reduce fuel use.

“It didn’t come as any surprise to us that EPA approved the waiver given the agency’s track record,” Glen Kedzie, vice president and energy & environmental affairs counsel at ATA, told Fleet Owner. “All along we thought they needed a waiver, but we knew the waiver would be approved.”

What was surprising and somewhat problematic was CARB’s delay in seeking the waiver, which it did several years after the regulations formally took effect, Kedzie said. “For the longest time, CARB said they didn’t need a waiver, and then they turned around and sought one. That left the trucking industry in an awkward position because so many fleets had already made the necessary capital investments to comply with the regulations.”

Many ATA members objected that the situation was inequitable because they had complied with CARB’s regulations while other fleets didn’t do so because CARB wasn’t enforcing the rules, Kedzie said. “We typically aren’t in a position of saying that a state needs to enforce its rules, but that’s the situation here.”

The controversy over unequal treatment under the HD GHG regs are similar to the concerns many fleets raised earlier this year when CARB pushed off compliance with the state’s Truck and Bus rule.

The question now is when CARB might begin enforcing the GHG rules. It could be that CARB will wait to see if any party seeks reconsideration by Oct. 6, Kedzie said. “They will be wise not to take any enforcement until any petitions play out.” Otherwise, CARB could be forced to reverse any penalties or enforcement action it takes in the interim.