The EU as a whole is much more consistent than individual countries, in fact, standardization is one of it's biggest strengths.

I used to work for the national vehicle registry in my country. European vehicles were easily registered using standard European "Whole Vehicle Type Approvals". Each new European car came with a type approval number linked to it's info, no problem.

American cars were a nightmare. Every new vehicle type came with it's own adventure of Googling or otherwise gathering information about the vehicle (number of doors, engine size etc...). Just no standards whatsoever. Horrible.