This piece strikes me as too Utopian. While most people,
including me, will likely adopt driverless cars, a substantial minority of the population will never adopt them.
Should driverless cars become mainstream, criminals of all kinds will quickly find ways to game the system to make vehicles driver-controlled, and (more ominously) will figure out how to hack into other people's cars and use them for nefarious purposes -- vehicle botnets that can cause major economic and physical damage. The police will need ways to override driverless vehicles to keep up with criminals.
Moreover, many individuals who love driving their sports cars don't want driverless vehicles; many law-abiding car hackers and tinkerers don't want to relinquish full control over their vehicles; and civil-rights organizations will likely end up fighting driverless vehicles in the courts.
Instead of an Utopian, smoothly-working, accident-free system that doesn't need police, seat belts, or insurance, I would expect our road-traffic system to evolve into a more complex mix of driverless and driver-controlled vehicles. The unintended consequences of the transition to this system, and its ultimate legal and technological requirements, are really unknowable at this point.
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PS. In response to paulsutter below, this is not "dystopian terrorist hacker paranoia!" All I'm saying is that the transition will be a lot less simple and smooth, and will have more unintended complex consequences, than suggested by this piece. That's usually how it goes when society makes fundamental changes to the architecture of a large, widely used, complex system!