Route Familiarity in Road Safety: Theory and Applications

Human factors are closely related to the causation of road accidents. Among them, the route familiarity plays an important role, since it can influence the driving task. The relationships between route familiarity and road safety are explored in this thesis from both a theoretical and an application point of view. A general background section is devoted to the explanation of all those possible relationships, as reported in literature. They concern the influence on the driving task, the driver behaviour, the perceived risk, the performances, the travel utility. A specific section is devoted to the practical involvements in road design and traffic engineering. The research work was focused on four different but parallel aspects connected to the main topic. The evolution of speeds and trajectories was inquired through the use of experimental data. The same data were used to investigate the possible changes in drivers’ perception. The potential impact of route familiarity on road accidents was firstly analyzed from a theoretical point of view based on exisiting frameworks. Thereafter, it was analyzed based on a traffic and accident database acquired in Norway, through different research steps. The highlighted relationships between route familiarity and road safety were used to draw conclusions and propose potential developments related to the road safety practice. Moreover, given the several measures of familiarity found in previous literature, a more detailed and unified definition for measuring familiarity was proposed. It is based on both time and distance scales, according to previous theories and findings.