[mmirate]

What about safety differences that don't affect pedestrians and other such (nigh-)stationary objects?

For instance, I could easily imagine that some cars might have more powerful kinematic-prediction software+processors and therefore are able to use smaller safety margins, allowing for more aggressive/liberal driving-behaviors than would be possible to safely perform in self-driving systems that aren't so well-endowed.

(Then again, depending on how good the first batch of general-purpose self-driving systems are, it may be possible that traffic safety margins among the self-drivers will be reducible enough that even the base models are "good enough" for anyone who doesn't encounter too many meatbag-drivers on their commute.)