A Preliminary Effort to Develop a Framework of Distance Decay Functions for New Urban Active Mobility

Sustainable mobility in urban areas has made a giant leap forward with the widespread diffusion of muscular bike, e-bike and e-scooter in the last years. There is therefore the need to provide new modelling tools for urban transport planners in order to manage the increase of these new transport users as far as the safety issues are concerned. Following a risk-based approach to urban road safety, evaluating the road network exposure to the new active modes (especially cycling ones), implies the use of suitable Distance Decay Functions (DDFs) that can be easily implemented in a travel demand prediction model. In this paper, a new methodology to develop DDFs is proposed. The method has been calibrated and applied to a dataset of over 90 Italian cities where land use and terrain data have been collected and regressed in order to evaluate a combined model taking into account modal split and trip distance. It is believed that the use of this method may help urban road designers and city planners in identifying critical traffic scenarios induced by new active mobility and in studying suitable countermeasures to improve traffic safety.