We've defined standards for humans that we find acceptable, in part because there is much that is implicit in the operator being a human. For example, a cop at

We've defined standards for humans that we find acceptable, in part because there is much that is implicit in the operator being a human. For example, a cop at an intersection, holding his hand up, then pointing left to redirect traffic is not something we test in a driver's test, but is something we expect human drivers to understand and obey. Perhaps the cars can handle this already, but there are likely hundreds, if not thousands, of these scenarios that are going to be necessary to think about now. There is also a lot of legal work that will begin as these roll out, especially dealing with liability, and these things take time that simply selling millions of these cars in 3-4 years will not allow for.