> In a driverless car case, someone is going to have to pay for that insurance, whether the manufacturer, operator or rider, that cost is going to come from someplace, and will probably be significant. I'm not sure that you could achieve 50% savings, and maybe not even 25%.

The fleet provider (e.g. Uber) would surely self-insure. Insurance for self driving cars will be extraordinarily cheap (at least an order of magnitude less than driver based insurance).