I think one of the main issues with liability here isn't the expected loss - I would be extremely surprised if driverless cars weren't much safer than ones with

I think one of the main issues with liability here isn't the expected loss - I would be extremely surprised if driverless cars weren't much safer than ones with drivers, at least once the major kinks are worked out - it's the correlation between accidents. Currently, accidents happen more or less at random; when controlled by software, a bunch of cars might go berserk at once, bankrupting an insurance company in a fit of bad zeroes and ones.