Transportation systems have profound ecological and evolutionary repercussions on biodiversity through habitat fragmentation and destruction, but roadkill is perhaps their most direct and spectacular impact. Despite the wealth of empirical studies documenting the spatio-temporal distribution of roadkill hotspots and their potential consequences on wildlife, surprisingly little has been done from a purely theoretical viewpoint. Here, we filled the gap by simulating random walk trajectories within specific scenarios of behaviour and habitat use - such as foraging or road avoidance patterns. We show that the local collision risks are driven by animal and vehicle density or speed only under specific circumstances. The well-documented saturating effect of high traffic flows is also formally demonstrated. Quantitative and qualitative predictions about the impact of vehicle speed, traffic flow, road and species characteristics derive from our model, for future empirical studies to build upon when investigating road-induced mortality on endangered fauna and planning mitigation measures