"Most people want to live in in a world where cars will minimize casualties," says Iyad Rahwan. "But everybody wants their own car to protect them at all costs."
I don't. Not at all costs. I don't drive that way and I wouldn't want others to, either, whether in a self-driven car or a self-driving car.
Take a hypothetical example. I'm driving down the street, observing all relevant traffic rules when an oncoming vehicle, for no apparent reason, swerves into my lane and is headed for a head-on collision with me. For the sake of this hypothetical, I have only two options, as in the above example-- to either allow the collision or swerve myself. The only available location to avoid a collision is occupied by multiple pedestrians who are also obeying the traffic rules.
Plenty of people would swerve reflexively and hit the pedestrians. If law enforcement and the legal system work properly, I would most likely be exonerated in this accident, and blame for any damage or injury suffered both by myself and the pedestrians would be borne by the driver of the other vehicle.
Which does nobody a damn bit of good if the pedestrians are dead, and possibly no one left to blame (except an insurance company) if the driver of the other vehicle also died in the collision. (Let's presume that if I avoid him, he hits the car behind me, killing that driver and himself. Just for the sake of argument.)
A human driver can defend themselves by saying they didn't mean to hit the pedestrians, perhaps that they didn't see the pedestrians prior to the accident; if they are not in a crosswalk and not competing with the car for right-of-way then there's no particular reason to have observed them.
The autonomous car has no such excuse. It might fail to avoid the oncoming car, it might fail to avoid hitting the pedestrians, but it will not be because it had no time to consider the possibilities or because it was frozen by indecision. I really don't think there's any way to approach this other than a utilitarian one. The car can't be expected to accurately compare the relative risks of damage, injury or death to the various parties. It can probably, however, be supplied with information about the number of occupants in the car and the number of pedestrians on the street.
I would hope I would not swerve into a dozen schoolchildren to save myself from an oncoming vehicle that is violating the regulations (for whatever reason) just to save myself and transfer the damage for which that vehicle's driver is responsible onto somebody else. If I can safely avoid him without significant involvement to bystanders, I should. If I can't, I should not. I should let them hit me, restricting the involvement in the accident, if possible, to the perpetrator and the one vehicle our example assumes will contain victims: mine.
Now, should my car hit other cars to save me? Presumably unoccupied, parked cars, for instance? Sure! Property alongside the road? Probably! Utility poles? Well, now we're getting into an area where the car won't and can't know what would happen, so probably the car should prioritize avoiding pedestrians and then structures like utility poles, but pay less regard to other cars, either stationary or moving.