Luckily she called the police (and me) and got a police report. The Tesla had video footage of rear ending my wife and my insurance claimed that the accident was 51% my wife and 49% the tesla guy.

It took a week for the police report to come available but there was a witness and the police report indicated that it was the Tesla dude's fault as well as the witness report and it changed to 100% tesla dude's fault.

So yes, calling the police is fair and will determine the correct outcome. If it is your wife's fault it will confirm that but if it's not her fault then a police report can confirm what really happened.

Good luck!