The Stop CARB Act of 2024 would eliminate California's ability to set its own vehicle emission standards and prevent other states from adopting California's standards. Currently, California has a special waiver under the Clean Air Act that allows it to establish stricter vehicle emission rules than federal standards, and up to 14 other states can choose to follow California's standards instead of federal ones. This bill would repeal that waiver authority, cancel any waivers already issued, and deny any pending waiver applications. The legislation would also repeal Section 177 of the Clean Air Act, which allows states to adopt California's vehicle emission standards. The bill affects automakers, states considering stricter emission rules, and air quality policy across the country, though it contains no specific funding provisions or implementation timeline beyond taking effect upon enactment.