Patterns of Police, Fire, and Ambulance Calls-for-Service: Scanning the Spatio-Temporal Intersection of Emergency Service Problems

Abstract

Independent analysis of police, fire, and ambulance calls for service demonstrates common patterns in emergency service activity. Targeted, place-focused interventions have been demonstrated to prevent future problems for emergency services. This research builds on these findings to examine the spatial and temporal intersection of police, fire, and ambulance incidents to explore the potential utility of enhanced collaboration between emergency-first responders. Using police and fire data from Surrey, BC, Canada, from 2011 to 2013, spatial and temporal patterns of police-, fire-, and ambulance-related incidents were examined. Initial analyses demonstrate that 36% of the City's area experienced 72% of incidents responded to over this 3-year study period. Focusing on this high-volume area, the spatial and temporal intersection of these incident types was explored. Spatially, lattices of varying cell sizes (250 m, 500 m, and 1,000 m) were placed over the study area. Temporally, incident volume was examined across the entire 3-year study period, and at yearly and monthly intervals. Incidents were placed within these spatial and temporal frameworks and visual inspection was utilized to assess the convergence of service demand. Regardless of the cell grid size, police, fire, and ambulance incidents were spatially and temporally concentrated, with the top 10% of cells accounting for approximately 50% of all incidents across all services. Furthermore, there was considerable spatio-temporal convergence in cells which account for the top decile of call volume for all incident types. A 2 × 2 typology is proposed to classify locations (in this case grid cells) based on (1) the frequency at which they generate high demand for services (sporadic versus persistent), and (2) the combination of agencies required to respond to high demand problems (single versus convergent). The spatial and temporal convergence of emergency service problems observed in this study suggests that an interagency approach to problem identification will enhance problem analysis processes. Working in conjunction with established problem-focused intervention strategies (such as problem-oriented policing), the volume-service typology provides a framework that can contribute to the development of appropriate problem-responses. This, we hope, will support emerging efforts to increase the extent to which emergency-first responder agencies collaborate to maximize efficiency and effectiveness, and reduce harm.