Spatiotemporal shifts in injury and fatal collision hotspots before, during and after the COVID-19 pandemic in Halifax Regional Municipality, Canada.

BACKGROUND: Motor vehicle collisions remain a persistent public health challenge, with risks often concentrated in specific locations rather than distributed randomly. While the COVID-19 pandemic altered mobility patterns and traffic volumes, limited research has examined how the spatial distribution of severe collisions evolved across pre-pandemic, pandemic and post-pandemic periods. METHODS: This study analysed injury and fatal collisions in Halifax Regional Municipality, Nova Scotia, using road collision records from 2018 to 2025. Collision records were aggregated into 1.5 km × 1.5 km spatial grids and divided into three periods: Pre-COVID (January 2018 to February 2020), COVID (March 2020 to June 2021) and Post-COVID (July 2021 to December 2025). Annualised collision counts were calculated to standardise time durations across periods. Spatial clustering was evaluated using the Getis-Ord hotspot statistic in a GIS environment, and hotspot transition analysis was used to identify persistent, emerging and diminishing clusters across periods. RESULTS: Injury-related hotspots remained concentrated in the Halifax-Dartmouth-Bedford urban core across all periods. The spatial extent of these clusters declined during the COVID period but expanded again afterwards. Fatal collision hotspots were more spatially dispersed, with several freeway-associated hotspots diminishing during the pandemic. In the Post-COVID period, fatal hotspots re-emerged in the urban core and expanded into surrounding inland areas, indicating shifting spatial risk patterns. CONCLUSIONS: Pandemic-related disruptions temporarily altered collision hotspot patterns, but clustering re-emerged as travel activity resumed. Persistent urban hotspots and emerging peripheral clusters highlight the value of spatiotemporal hotspot analysis for guiding targeted road safety interventions.