The importance of human factors, in road design and traffic safety, has been increasing recently. As part of the human-centered design, schemata, as mental representations, induce road user expectations, as well as, trigger behavioral patterns. In road design this concept is called “self-explaining roads”, meaning that road users automatically drive according to an expected behavior and speed. This requires different categories of roads, each with homogenous characteristics and a notable difference between them. This paper investigates how many unique categories road users are able to recognize.