Geographic determinants of vehicular speeding in British cities

Vehicular speeding remains a major challenge in urban and transportation planning. Its prevalence in cities arises from a complex mix of social and spatial factors, and a suite of countermeasures are now built into road infrastructure to mitigate its impact. Yet our understanding of how urban context influences speeding is less clear, and we have little sense of the spatial scale at which urban form shapes speeding behaviour. In this paper we undertake a large-scale, comprehensive analysis of speeding behaviour across 13 British cities, using vehicle trajectory data from 3.2 million journeys. Unlike prior studies, we assess determinants of speeding across multiple scales - from local engineering interventions to regional measures of road network configuration. The results indicate that road geometry and network connectivity have a strong causal relationship with speeding behaviours, higher in general than engineering interventions. These findings have two clear implications for cities and urban science. First, changes to urban planning, including those to reduce speeds, should consider the impact of configurational changes in addition to local interventions. Second, more broadly, measures of local spatial behaviour should account for wider contextual urban indicators, reflecting the nature of human spatial perception.