How long before cars are zero-day susceptible to remote wireless hacks that can endanger lives of the passengers?
I have seen conspiracy theories about acceleration and brakes being tampered with, but those allude to the tampering while the car was stationary.
When a vehicle has so much code in it, control systems are fly-by-wire, and there is bluetooth and wifi access, it is not a stretch to imagine a malicious entity driving on the highway and taking over nearby vehicles.