In Oregon, for example, the DMV arbitrarily refuses to register them for any use whatsoever. It's not a law or regulation, it's more like an internal opinion or rumor that turned into a standard practice of refusal. They'll still happily give you plates and registration for your even smaller and slower Fiat 500, Subaru 360, Isetta, etc. - but if a DMV employee assumes it's an imported Kei car, you're out of luck.
Because it's not a defined rule (despite mentioning it on their website!) even non-Kei Japanese imports are risky to register. Sometimes a DMV employee will see a car they assume is Kei or close enough because it looks funny, and they'll write down the plate number and void the registration later.
If you're a business and register it with your business, that seems to mollify the DMV for some reason. A few Kei pickups and vans with Oregon plates and business logos have been roaming the local streets.
It's also somewhat common to see Kei cars driving around in Oregon from neighboring states. Totally legal for highway use in Oregon, the Oregon DMV just won't register them.
It has it's own section: "Kei Vehicles/Mini-Trucks"
"Many of these vehicles can be imported. They can be titled in Oregon, but cannot get registration because they were not primarily manufactured for U.S. roads or highways."
Perhaps it is still arbitrary, not supported by a specific regulation (but I don't know that). Still, they aren't hiding their unwillingness to register them.
In Oregon, for example, the DMV arbitrarily refuses to register them for any use whatsoever. It's not a law or regulation, it's more like an internal opinion or rumor that turned into a standard practice of refusal. They'll still happily give you plates and registration for your even smaller and slower Fiat 500, Subaru 360, Isetta, etc. - but if a DMV employee assumes it's an imported Kei car, you're out of luck.
Because it's not a defined rule (despite mentioning it on their website!) even non-Kei Japanese imports are risky to register. Sometimes a DMV employee will see a car they assume is Kei or close enough because it looks funny, and they'll write down the plate number and void the registration later.
If you're a business and register it with your business, that seems to mollify the DMV for some reason. A few Kei pickups and vans with Oregon plates and business logos have been roaming the local streets.
It's also somewhat common to see Kei cars driving around in Oregon from neighboring states. Totally legal for highway use in Oregon, the Oregon DMV just won't register them.