A 1995 Nissan Skyline that clears the federal 25-year import exemption without any paperwork trouble can still be turned away at a California smog-check station, flagged at a Massachusetts safety inspection for its headlight beam pattern, or hit with an emissions test in Maryland that a federally exempt car in a neighboring state never has to take. Federal law and state law are answering two different questions, and the gap between them is where most of the real friction in JDM ownership actually lives.

What Federal Exemption Actually Grants

The 25-year rule is a narrow, specific carve-out. It means a vehicle “at least 25 years old can be lawfully imported into the U.S. without regard to whether it complies with all applicable” federal safety standards, according to NHTSA’s own guidance, and importers document that age to Customs using form HS-7 at the border, per CBP’s published import requirements. That’s it. The exemption is a federal statement that the vehicle doesn’t need a Registered Importer, a compliance bond, or FMVSS modifications to enter the country. CBP’s own guidance is explicit that this is only half the equation, warning importers that “individual state emission requirements may differ from those of the federal government” and that “proper registration of a vehicle in a state may depend upon satisfaction of its requirements” — meaning the agency that clears a car for entry is directly telling buyers, in writing, to check with a completely different authority before assuming they’re done.

California Adds Its Own Layer on Top

California is the state most often cited for extra friction, and for good reason: it runs its own emissions authority independent of the federal exemption. According to a state-by-state registration breakdown compiled by import specialists, the California Air Resources Board requires imported vehicles to meet state-specific compliance standards, a process that can run into the thousands of dollars and isn’t guaranteed to succeed for every model, and any car showing aftermarket parts or engine modifications during a Bureau of Automotive Repair referee inspection fails outright. A federally exempt 25-year-old JDM car doesn’t get a pass on any of that — CARB’s authority operates independently of the federal age exemption, which is why California has developed a reputation among importers as the hardest state to register a grey-market car in, regardless of how clean the car’s federal paperwork is.

The “Exempt But Still Inspected” States

A separate category of states exempts older vehicles from emissions testing but still requires them to pass a standard periodic safety inspection — and RHD cars can run into inspection criteria that were never written with a right-hand steering position in mind. The same import-industry registration guide notes that Massachusetts and New York both drop OBD-II emissions testing once a vehicle crosses 25 years old, but both still require an annual safety inspection regardless of import status, with imported RHD vehicles sometimes flagged for headlight beam patterns calibrated for left-side traffic rather than U.S. roads. Connecticut, by the same account, goes a step further in the other direction, requiring an OBD-II test specifically for vehicles that are exactly 25 years old rather than applying the exemption immediately at the threshold — a detail that trips up owners who assume the federal and state clocks tick in perfect sync.

Why This Catches So Many Buyers Off Guard

Most of the marketing language around JDM imports focuses entirely on the federal side because that’s the dramatic, headline-friendly number — 25 years, one clean rule, nationwide. State DMV and inspection requirements don’t lend themselves to the same simple pitch, because there are fifty different answers depending on where the buyer actually lives, and those answers change based on emissions rules, safety inspection regimes, and sometimes county-level requirements layered on top of state ones. A buyer who does all their research on the federal exemption and none on their home state’s registration process can end up with a perfectly legal import, sitting in a garage, that their own DMV won’t put a license plate on.

The Real Lesson in the Patchwork

The federal 25-year rule was never designed to be the whole story — it’s a floor, not a guarantee — and the actual determinant of whether a RHD import ever turns a wheel legally on public roads comes down to a patchwork of state-level rules that have nothing to do with how old the car is and everything to do with which side of a state line it happens to land on.