I'd be pretty wary of pushing information like this out in the open without first making sure the vendor had time to alert their customers that his is about to hit the streets. Who knows what kind of vehicles we're talking about and under what conditions they operate. Of course it isn't rocket science, but that doesn't mean you need to advance your stature in the security community by blindsiding some manufacturer on Sunday evening.

Anyway, call me old-fashioned, I don't think this is the way it should be done.

FWIW I'm aware of a SCADA system that is widely deployed that is just about as secure as this system here and I'd be the last person on the planet to publish the details of it because I know for a fact that it is used to control HVAC equipment and other building infrastructure in hospitals and prisons. These things are not toys and being aware of them does not actually allow you to play god. (In that particular case as far as I know the systems are so old that fixing them with an update is not even an option).