Am I the only one who's terrified of the security implications of such a system? You're talking about running (from the car's perspective) untrusted code on a fleet of cars, dynamically and in real time. Even if it's cryptographically signed or whatever, you're one or a handful of exploits away from remote attackers having the capability to crash every autonomous car, simultaneously, at least in a geographical region and possibly (inter)nationally.
If security matters today, it's going to matter orders of magnitude more in a world with autonomous cars.
I read the other day about geofencing being used to enforce speed limits for rental ebikes and scooters in some jurisdictions. It's not hard to imagine it progressing from speed limits to top-down traffic control programs. This probably is the future we're hurtling towards, as unprepared as ever.
If security matters today, it's going to matter orders of magnitude more in a world with autonomous cars.