Is Emissions Testing for Older Vehicles Still Relevant?

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      Depending on your location in the United States, emissions testing for older vehicles may or may not be relevant. There are 28 states where some, but not necessarily all, older cars are required to undergo smog testing. Most of these have age thresholds, typically mandating tests only for vehicles that are 20 or 30 years old at most. Then there’s California.

      California mandates that any vehicle manufactured since emissions regulations were established (1976) must be tested biennially—no exceptions. This creates substantial pressure on owners of cars from the 1970s to the 1990s to maintain compliant emissions systems, often at costs that can surpass the vehicle's value. Automakers are obligated to provide replacement emissions parts only for the first decade following a car's production. After that, it falls to the aftermarket to provide those parts. For enthusiasts of niche cars produced in limited quantities decades ago, this situation can be particularly challenging.

      Leno’s Law aimed to change this by removing smog checks for vehicles older than 35 years. As you might infer from its title, the bill was strongly advocated by Jay Leno, and it also received support from SEMA and other lobbying organizations. However, it has now failed. Introduced during the 2025 California State Senate session, the bill stalled in committee. Supporters lost enthusiasm when concessions to opponents imposed additional burdens on car owners, ultimately resulting in insufficient support for a final vote. The last committee discussion occurred in August.

      So, what’s next? The brief answer: data.

      Most arguments advocating for the bill suggested—but did not provide evidence—that the real-world emissions impact would be minimal. Enthusiasts argue that they do not use their classic cars for daily driving, thus limiting their overall contribution to smog. However, anecdotes were not convincing enough for lawmakers during the initial discussions. The current regulatory environment may be more favorable for reducing collector car emissions than it has been in recent memory; however, this approach is unlikely to yield the same results in California as it might in Wyoming or the southern states.

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