Y'know, that's a good point. Flow of traffic on several highways around here is 15mph above the speed limit. People are going to hate self driving cars on those unless the speed limit goes up. Maneuvers to avoid or pass them may well make the highways more dangerous, while human drivers are still in the majority.

The article links to Rodney Brooks, who mentioned this in a recent blog post http://rodneybrooks.com/unexpected-consequences-of-self-driv...:

> At least one manufacturer is afraid that human drivers will bully self driving cars operating with level two autonomy, so they are taking care that in their level 3 real world trials the cars look identical to conventional models, so that other drivers will not cut them off and take advantage of the heightened safety levels that lead to autonomous vehicle driving more cautiously.