tsunamiofhurt
Member
NHTSA's role here is simply to take a consumers request (i.e. does my vehicle have any open safety recalls?) and pass it on to the manufacturer via a secure API. The result of that query is then displayed to the consumer on the NHTSA/safercar.gov website. For privacy reasons, the data from these requests is not retained by NHTSA in any way. This was deemed to be a simpler and more cost-effective approach than each of the manufacturers sending data dumps to NHTSA on a daily basis to be stored in some centralized way.
So, NHTSA definitely does not charge per VIN "registered". The meaning of "register", in this context, is something more like "NHTSA has registered a response in Tesla's database for VINs XXX-XXX".
As to the rules that govern when Tesla decides to populate their database with new VIN numbers? Who knows. However, as you rightly point out, it's a useful data point that gives us insight into the larger production picture. We know that it's a ceiling because a manufacturer wouldn't be able to deliver a car that can't then be queried by the consumer taking delivery. We can also draw some concrete conclusions from the VIN registrations because of the information contained within the digits (e.g. dual motor registrations, total # of MY 2017 VINs, etc.).
