Use of information in decision-making about road safety measures; Study in twelve Dutch provinces This study investigates what information provinces use in decision-making about the construction of infrastructural road safety measures on provincial 80km/h roads. The following questions are answered in this study: - Do provinces use general information about costs and effects, and specific information for each possible measure on an 80km/h road in their decision process? - Does this use determine whether or not infrastructural measures on 80km/h roads are carried out? In interviews with policymakers and road designers in twelve provinces different ways were used to find out which information is used, and in which way according to the Knott & Wildavsky (1980) scale it is used. The questions are aimed at three stages on this scale: reading and understanding of the information ('cognition'), the effect on the picture of reality ('reference') and the effect on the policy outcome ('adoption'). The interviews consisted of three parts. First the question was asked whether, both in general and per measure, information about costs and effects is used in decision-making about road safety measures ('reference'). Secondly, the interviewees were handed a brief list of relevant publications with the question which of the information they know and which they use in their decision-making ('cognition' en 'reference'). Thirdly, the interviewees were asked which measures they do and which they do not carry out on their 80km/h roads and for what reason they do or do not. This way it was attempted to relate the used information to the policy outcome and to get an idea of possible 'adoption'. Use of cost and effect information Approximately half of the provinces say they have an idea of the costs and effects of road safety measures on 80km/h roads. Provinces say they have a clearer picture of the costs than of the effects. Two thirds say that cost and effect information is to some extent important in the decision-making, if the picture of the costs and effect is not complete. However, it frequently happens that provinces carry out measures of which the effects (and to a lesser extent the costs) are completely unknown. Most provinces extract the knowledge of the effects of measures from their own crash studies. To a much lesser extent literature is used from outside their own organization. At design level much use made of CROW publications; literature from research institutes like SWOV and TNO is used at policy level Publications are not used if they are not in line with the province's road safety view. Besides publications the (provincial) network is also used to gather information. Construction of road safety measures All provinces construct bicycle paths and roundabouts, and practically all provinces use obstacle-free zones, crossing facilities for cyclists, and roadside safety constructions for their roads. Less than half the provinces construct plateaus and passing spaces. The provinces say that most of the measures were taken for road safety reasons. Only parallel roads and passing spaces are sometimes constructed for reasons of accessibility. The reasons provinces sometimes give for not constructing a measure give an indication of the barriers that provinces experience to stand in the way of an optimal use of the knowledge of the measure. The most important reasons are: - lack of space to carry out a measure (particularly for the obstacle-free zone); - maintenance susceptibility of measures (particularly for the raised carriageway separation); - not being convinced of the effect (particularly for the raised carriageway separation and the matted shoulder); - the idea that a particular measure will prevent only few crashes or no crashes at all (several measures); - being in conflict with other provincial policy (several measures); - objections by citizens (particularly the plateau, parallel road, rumble strip). In addition to these reasons provinces also mention 'Too expensive' as an important practical objection (particularly for crossing facilities for cyclists, obstacle-free zones and matted shoulders). Continuation of the study Because this study is part of a series, no recommendations are given. The results from this part of the study are used to set up an experimental study in which provincial policymakers are presented with a number of fictional cases with information about 80km/h roads and about infrastructural road safety measures.