A proposed California ruleset could wreak havoc on the tire and automotive industries by effectively banning the sale of aftermarket tires. California's proposed "Replacement Tire Efficiency Program" would set standards requiring all aftermarket tires to be at least as efficient as the tires sold on new cars.While the proposed regulations could improve fuel-economy figures, they would also significantly shorten the average lifespan of a tire—resulting in more tires being manufactured and replaced.