I don't think it's as simple a picture as you paint. The world is not a static place, and there will always be cases where human judgement is required. Consider for example ice roads or mountain passes: thousands of people may ride them on a single day, and the next day the road may be closed off because of frost, thaw or avalanche danger. There is no way you want your car to only consider a different route after ten drivees have lost their life.