When the road layout becomes persuasive for the road users: A functional study on safety and driver behaviour

The paper describes a research aimed at investigating drivers’ behaviours in two experimental setups, a real and a virtual environment. A road layout characterized by a S-shaped curve has been considered. The aim of the research was to appraise the relationship between the human behaviour and the road geometry. First of all, the results show a delayed speed adaptation when approaching the same curve in various conditions, in both environments. The authors investigate when and where each driver acts, and how his action is influenced by the perception of the layout, as it is guaranteed by markings (standard and reinforced by retroreflective post-delineators). Different driving scenarios are examined, concluding that improved road markings: usually permit a better perception of the road, especially of the curve stretches, and a general reduction of average speed; sometimes have a not positive effect, specifically where there is a variation of the size of the roadway; have a negative role on the long straights; decrease the scattering of driver behaviours. The research also suggests a practical criterion for selecting calibration sections of the speed diagrams, in order to assure a good accordance between virtual and real environment.