Zichtcriteria voor wegen en informatiedragers langs de weg. In opdracht van het Directoraat-Generaal Rijkswaterstaat, Dienst Verkeerskunde DVK.

A literature survey is made with regard to terms and criteria that are used for the measurement and assessment of sight distances on the road. The existing terminology is rather confusing and it is recommended therefore to use the word "sight distance" as a unique term for the measurable, available sight. With respect to the required sight distances it is proposed to use the additional word "criterion", like stopping sight distance criterion, that is to say the sight distance required for safe stopping. With respect to the knowledge underlying the different sight distance criteria, it is concluded that the passing sight distance criterion is presently quite well motivated. The decelaration levels used as an element of the stopping sight distance criterion are considered to be considerably larger than those normally accepted by drivers. Furthermore, the perception-reaction time value of 1.5 or 2 seconds for rural roads is considered too low. Most of the criteria lack a fundamental knowledge about the relation between sight distance and actual speed choice. The passing sight distance criterion is presently quite well motivated. The deceleration levels used as an element of the stopping sight distance criterion are considered to be considerably larger than those normally accepted by drivers. Furthermore the perception-reaction time value of 1.6 or 2 s for rural roads is considered too low. The solidness of the intersection sight distance criterion should be improved by gathering more knowledge about gap-acceptance in limited sight distance conditions. Most of the criteria also lack a fundamental knowledge about the relation between sight distance and actual speed choice. It is recommended also to consider geometric sight distance in close relation with the visibility requirements of roadside information like signs, delineation etc. Finally it is indicated to be useful to develop a "design driver" concept, which involved most of the static and dynamic properties of an representative observer and which can be used as a standard design element.