California approves replacement tire efficiency standards

Sacramento, California – The California Energy Commission (CEC) has unanimously approved the nation’s first efficiency standards for replacement tires, a programme that is expected to save state drivers $1 billion (€860 million) a year in fuel and electricity costs while cutting CO2 emissions.

Approved by CEC commissioners 17 Aug, the Replacement Tire Efficiency Program (RTEP) applies to replacement tires sold for passenger vehicles and light-duty trucks in California.

The first phase of the programme will start in 2029, with the standard coming into full effect in 2033.

Under the initial phase, base passenger car tires will be subject to a maximum rolling-resistance coefficient of 9.0, measured according to the ISO 28580:2018 test protocol. The threshold will tighten to 7.1 under Phase 2.

Different efficiency requirements will apply to other tire categories, including light truck tires, low-load-index tires, long-life tires, ultra-long-life tires and ultra-high-performance tires.

All replacement tires covered by the regulation will also be required to meet a minimum wet-grip value of 1.0, based on the ISO 23671:2021 test method.

In its official statement 17 Aug, the CEC said the standards are designed to ensure replacement tires are “at least as energy efficient, on average, as tires sold on new vehicles”.

“Tires that come on new cars are typically designed to give drivers better fuel mileage,” the commission said.

However, it noted, average replacement tires are less efficient, meaning that consumers often lose mileage and range when they replace their tires.

According to CEC chair David Hochschild, the programme will help Californians save nearly $1 billion a year on refuelling while reducing CO2 emissions by 2 million tonnes per year, equivalent to taking 400,000 petrol cars off roads.

The commission said the incremental cost to consumers will be “very low”, at $1.50 per tire during the first phase, covering 2029-2033, and $6.50 per tire during the second phase which will cover from 2033 onwards.

According to CEC, a typical driver of a petrol car using more efficient tires will save $179 in fuel over the life of a set of tires.

The calculation is based on gasoline prices of $4.60 per gallon. At the elevated gasoline prices of mid-2026, the CEC said, savings “could be 25% higher than estimated”.

The commission added that replacement tires meeting the standards are already available.

In response to the decision, Michelin North America supported the efficiency goals and said the proposed thresholds were technically achievable.

“California's direction is consistent with Michelin’s all-sustainable and holistic approach for reducing the impact of tires at every stage of the life cycle," said Francesca Mosteller, director of state & local government affairs at Michelin North America.

“We support the efficiency goals and believe the proposed thresholds in this rulemaking are technically feasible within the defined timeframes,” she added.

The CEC said it conducted extensive laboratory testing of “the most popular replacement tires” in California and reviewed “best-in-class industry data” from companies including Discount Tire.

The analysis confirmed that the regulation was “cost-effective and feasible”, with “no adverse tradeoffs with tire lifespan, safety, or other characteristics”, according to the commission.

The CEC also said that it undertook a five-year stakeholder engagement process with the tire industry, including manufacturers and trade associations.

Based on industry feedback, the commission said it has carved out exceptions for certain speciality tires, including sports tires, large off-road tires and all-weather winter performance tires.

It has also created product categories for long-life tires, ultra-high-performance tires, low-load-index tires and other tires with special characteristics.

“As the CEC implements the replacement tire efficiency standard, it will continue to work with stakeholders and ensure equitable and effective enforcement,” the commission said.