On August 17, 2026, the California Energy Commission (CEC) adopted the Replacement Tire Efficiency Program (RTEP) requiring most replacement tires for cars and light-duty trucks in California to meet minimum efficiency and performance criteria beginning in 2029 and ratcheting up in 2033. The rules are aimed at ensuring replacement tires sold in California are generally as energy efficient as tires on new cars and trucks. With this action, California is once again leading the federal government in setting regulations to address vehicle efficiency in the U.S.
New Requirements for Replacement Tires Installed on Vehicles in California
Passenger car replacement tires sold or offered for sale in California that were manufactured on or after January 1, 2029, must have a rolling resistance coefficient of 9.0 newtons per kilonewton (N/kN) or less, while the maximum limit for those manufactured on or after January 1, 2033, drops to 7.1 N/kN. Light-duty truck replacement tires and certain high-performance replacement tires have different requirements in recognition of their different use cases.
In addition to the efficiency limits, replacement tires must meet a wet-grip minimum standard based on International Standards Organization (ISO) protocols to ensure adequate traction as tire formulations are adjusted for compliance. Also, CEC adopted a “leaf” rating system intended to allow consumers to quickly identify replacement tires with greater or lesser efficiency.
To minimize burdens on specialty and niche replacement tires, the following replacement tires are exempt from the minimum performance standards:
- Competition tires designed for motorsports
- Winter-type snow tires
- All-season winter performance tires
- Used and retreaded tires
- Deep tread tires
- Tires designed for ATVs and other off-road vehicles
- Large off-road tires for use up to 99 mph
- Motorcycle tires
- Temporary-use spare tires
- Small tires with ≤13-inch nominal rim diameter
- Limited production tires (<15,000 per year sales in the U.S.)
- Tires sold for use on an emergency vehicle
- High load index tires (122 or greater)
- Tires not capable of sustaining speeds over 50 mph
- Space saver tires
- Tires that the manufacturer has not labeled with a tire identification number under 49 C.F.R. Part 574.5(a)(1).
Demonstrating Compliance with the CEC Regulations
Tire manufacturers or brand owners (the entity whose brand name is associated with the tire) must test, certify, and report to the CEC using specified procedures demonstrating that each replacement tire meets regulatory limits, and CEC will maintain a publicly accessible database identifying such compliant replacement tires. CEC may conduct audits, perform random sampling for testing, and conduct spot checks to ensure replacement tires registered in their database meet the claimed rolling-resistance coefficients (N/kN) and wet-grip safety criteria.
While either the physical tire manufacturer or the brand owner may submit compliance data to the CEC, both can be held liable in the event of noncompliance with tire performance requirements. The CEC holds statutory authority to test replacement tires at the manufacturer’s or brand owner’s expense or initiate judicial action for noncompliance. Further, if a tire model fails compliance testing or is otherwise found to be inappropriately certified, the CEC can remove it from the public database of approved tires, which prevents the tire model from being sold or offered for sale in California.
Tire retailers—defined as any “tire dealer or tire distributor of replacement tires or limited production tires”—generally rely on manufacturer certifications and the CEC public database listings to determine if a replacement tire complies with the RTEP. Beginning January 1, 2029, tire retailers selling into the California market may only sell replacement tires listed in the CEC database. Knowingly stocking, advertising, or selling replacement tires that are not listed on the CEC database or have been removed from the database can expose the tire retailer to enforcement actions. Tire retailers are also required to provide replacement tire information to consumers, although the regulation provides some flexibility in executing this obligation.
Vehicle owners are not subject to specific requirements or obligations under the CEC regulations. Compliance is largely ensured upstream of the final purchase of replacement tires by consumers.
Estimated Benefits and Costs of the Regulation
The CEC estimates the program will save nearly $1 billion per year on fuel costs in California (both gasoline and electricity for plug-in vehicles), reduce demand for gasoline by 141 million gallons, reduce electricity demand by 0.9 terawatt-hours, reduce CO2 emissions by 2.0 million metric tons per year, and reduce other pollutants such as nitrous oxides and particulate matter.
With an estimated cost impact of $1.50 per tire during the initial phase (2029 to 2033) and $6.50 per tire in 2033 and beyond, the CEC estimates the regulation will save consumers money with a payback period of between 3 and 7 months.
Looking Ahead
Regulated entities—including replacement tire manufactures, brand owners, and tire retailers—would benefit from closely monitoring future developments while also taking appropriate and necessary steps to ensure compliance.
Replacement tire retailers will need to begin planning how to manage their inventories leading up to both the 2029 and 2033 compliance windows to avoid stranding unapproved replacement tires in inventories.
The CEC’s RTEP is the first of its kind in the U.S. As such, unforeseen issues, the need for regulatory interpretations and clarifications, and the potential for missteps could all occur. And while the CEC spent significant time engaging with the regulated industry, the public, non-governmental organizations, and other stakeholders, the RTEP and related rulemakings could face legal challenges that may cloud future requirements and frustrate business planning.
Additionally, California often sets the stage for other states to follow. Regulated parties should consider how potential expansion of the CEC requirements to other states might affect their businesses. Similarly, while the new CEC regulations apply to passenger cars and light-duty trucks, medium- and heavy-duty vehicle replacement tires could also become a target for future regulations.
This program comes as California and the federal government continue to litigate the state’s new vehicle emission standards and follows on the heels of EPA’s recent endorsement of third-party testing of aftermarket emission components, described in part as aimed at reducing national reliance on California’s aftermarket parts certification program. While this splintering of the replacement tire market stands in contrast to those changes, the CEC’s authority to enforce energy efficiency standards has been well established through its work on a wide range of consumer products, including light bulbs, televisions, and appliances.
For More Information
Van Ness Feldman closely monitors and counsels clients on regulatory and policy developments under California and federal environmental programs. For further details or assistance with assessing the impacts of RTEP, please contact
Britt Speyer Fleming or any member of VNF's Environmental Team.