I think the idea is very good. However I have some concerns about it. For example, how to proceed with vehicles that had a serious accident? There are lots of vehicles in Europe (especially from Lithuania) where one car actually consists of 3 or 2. Also many people do some changes to their cars by themselves, so it would be hard to track such changes. Even if all data about car is recorded to blockchain you cannot put there information about how car was used that is also have a big influence on the car condition. In my opinion, the idea is good for limited number of cases.