They're on sale in Europe where the car safety standards are slightly different to the US, but generally considered more rigorous.
But yes, the vehicles which aren't on sale typically haven't been homologated. Why invest the time and money in that when it's not needed?
Actually deemed unsafe and not meeting the rules is much rarer, e.g. Tesla CyberTruck in Europe. (2)
In either case, you may get away with owning it, but not driving it on public roads.
1) https://en.wikipedia.org/wiki/Homologation https://www.productipedia.com/kb/productipedia/compliance-re...
2) https://www.theguardian.com/technology/2024/oct/08/tesla-cyb...
I wouldn't be surprised if they've already designed the core components of their cars (like the chassis) that they sell in Europe to meet American standards anyway. Stuff like the height and orientation of headlights can be modified more cheaply later when they want to enter the US market.
Insurance would need to be from a specialty provider who do insure oddball vehicles. Someone I know (in CA no less) insured his homemade electric motorcycle this way. (It’s titled as the chassis of the BMW regular motorcycle it was built from.)
If you’re pulled over, you would need to show things like seat belts or turn signals and so on. I got nailed for not having a shoulder belt in a homemade vehicle made after 1960. Seat belt ticket was my punishment, although the cop remarked that adding a shoulder belt would be a good idea.
As I understand BYD use less components than the other traditional car manufacturers (more brains/integration in axle vs having lots of CAN connected shit around the car) so in theory I could see builders installing a BYD drivetrain into an old chassis the same way people can do LS swaps into Miatas.
This article has some info about it and other things: https://www.jalopnik.com/here-s-how-people-illegally-import-...
Even by sketchers and jorts standards that's still, wow. The way that article is just dripping with post-boot saliva is a great illustration of the gulf between high class "porche or miata + Land<cruiser/rover>" type car enthusiasts and "buys whole cars for parts" type enthusiasts. Hopefully Doug's opinions have, uh, refined, over the last decade. Can't see how they wouldn't have.
What's legal per the law is a tiny fraction of what you can put on a DMV form and have the form get past the clerk and process properly which itself is a tiny fraction of what the cops will go after.
Scrapyards will take fractions of cars without asking questions. People who part out cars or deal in scrap metal know this and will take anything off your hands for free as long as the work vs what they're getting pencils out.
Even if they know you they'll never take a full car body in one piece without a title or any of the other "open and shut case" violations of law because they don't wanna risk getting Randy Weaver'd because a good customer had government problems and became an "informant".
The border crossing there is very busy so that could be a annoying.
Buying a HMMWV (Humvee) is no problem and they can generally be registered in most states. Thousands of them were also sold new directly to civilians as the Hummer H1.