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.