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April 3, 2025 – Daimler Truck North America (DTNA) today issued a formal statement addressing the California Air Resources Board (CARB) proposed replacement tire efficiency standards, marking a significant regulatory milestone for the commercial trucking sector. The requirements, aimed at reducing rolling resistance and improving fuel economy on replacement tires, would apply to all medium- and heavy-duty trucks operating in the state.
DTNA’s response acknowledges the environmental goals of the initiative while emphasizing the need for pragmatic implementation timelines and technical feasibility. The company—a leading OEM in the North American truck market—stressed that the standards must align with existing vehicle design parameters and aftermarket availability of compliant tires.
The proposed regulation, under CARB’s Low Carbon Fuel Standard and Advanced Clean Fleets framework, targets replacement tires sold after 2027. It mandates that replacement tires achieve a minimum fuel efficiency rating, measured by rolling resistance coefficient (RRC) in kg/ton. For steer tires, the target is RRC ≤ 6.5; for drive and trailer tires, RRC ≤ 7.5. These thresholds mirror those already adopted in the European Union under UN Regulation 117.
CARB estimates that the rule could reduce greenhouse gas emissions by up to 1.2 million metric tons annually by 2035, equivalent to removing 250,000 passenger cars from roads. However, fleet operators and tire manufacturers have raised concerns about cost, availability, and performance trade-offs in wet traction and tread wear.
In its statement, DTNA expressed broad support for the efficiency targets, citing its own investments in aerodynamics, low-rolling-resistance tires, and electric truck platforms. “DTNA believes that efficient tires are a critical component of a sustainable transportation system,” the statement read. “However, the transition must be carefully managed to avoid disrupting fleet operations and to ensure that tire technology matures sufficiently.”
The company specifically called for:
Industry analysts note that DTNA’s role as a major OEM means its stance could influence both CARB’s final rulemaking and the aftermarket supply chain. “If the largest truck maker in North America is raising concerns about tire availability, CARB will have to listen,” said Mark Henderson, a transportation policy researcher at the American Transportation Research Institute (ATRI). “Fleets could face a shortage of compliant tires in the early years, especially for less common sizes.”
DTNA’s own validation tests suggest that achieving the proposed RRC targets is feasible with current tire technology, but only if manufacturers invest in new compounds and tread designs. The company’s engineering team noted that “the trade-off between rolling resistance and wet braking is still significant, and we need to see more data from independent testing before we can guarantee safety.”
CARB is expected to hold a public hearing in June 2025, with a final vote slated for late 2025. If approved, the rule would take effect January 1, 2027, for replacement tires sold in California, with enforcement starting July 1, 2027. DTNA has committed to providing technical comments to CARB by the end of this month.
Meanwhile, the Tire Industry Association (TIA) has announced its own compliance guide for fleets, and several major tire brands—including Michelin, Bridgestone, and Goodyear—are accelerating their low-RRC product lines. DTNA’s statement serves as a bellwether for how the industry may navigate the most ambitious tire efficiency regulation in U.S. history.
DTNA’s carefully worded statement reflects the broader tension between environmental ambition and operational reality. While the company supports the goal of cutting fuel consumption and emissions, it insists that the transition must be smooth, safe, and economically viable. The coming months will reveal whether CARB adjusts its targets to accommodate OEM concerns—or whether the trucking industry faces a sudden shift in tire replacement costs.
For now, fleet managers should monitor CARB’s rulemaking docket and begin evaluating their tire procurement strategies. Early adopters of low-rolling-resistance tires may find themselves ahead of the compliance curve, but the industry-wide shift will require collaboration across the supply chain.
