The difference in vehicle regulations between the EU and US are not along a linear scale of rigor. They have different requirements for different things. They are different opinions of what “safe” even means.

Creating massive blindspots by making the outside mirrors magnifying is one of them.

For whatever reason, the industry term for the certification is "Homologation" (1)

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...

And Chinese cars rate higher on the European safety metrics than Western cars. https://insideevs.com/news/779537/euro-ncap-safety-rating-ch...

They probably just haven't done it yet since it's a self certification where the manufacturer themselves runs tests following NHTSA test procedures. Importers won't import (and probably can't sell in many jurisdictions) without that self-certification and it's likely just not worth it for BYD right now with the 100% tariff.

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.