Effect of a new motorway on social-spatial patterning of road traffic accidents: A retrospective longitudinal natural experimental study

Abstract

BackgroundThe World Health Organisation reports that road traffic accidents (accidents) could become the seventh leading cause of death globally by 2030. Accidents often occur in spatial clusters and, generally, there are more accidents in less advantaged areas. Infrastructure changes, such as new roads, can affect the locations and magnitude of accident clusters but evidence of impact is lacking. A new 5-mile motorway extension was opened in 2011 in Glasgow, Scotland. Previous research found no impact on the number of accidents but did not consider their spatial location or socio-economic setting. We evaluated impacts on these, both locally and city-wide.MethodsWe used STATS19 data covering the period 2008 to 2014 and describing the location and details of all reported accidents involving a personal injury. Poisson-based continuous scan statistics were used to detect spatial clusters of accidents and any change in these over time. Change in the socio-economic distribution of accident cluster locations during the study period was also assessed.ResultsIn each year accidents were strongly clustered, with statistically significant clusters more likely to occur in socio-economically deprived areas. There was no significant shift in the magnitude or location of accident clusters during motorway construction or following opening, either locally or city-wide. There was also no impact on the socio-economic patterning of accident cluster locations.ConclusionsAlthough urban infrastructure changes occur constantly, all around the world, this is the first study to evaluate the impact of such changes on road accident clusters. Despite expectations to the contrary from both proponents and opponents of the M74 extension, we found no beneficial or adverse change in the socio-spatial distribution of accidents associated with its construction, opening or operation. Our approach and findings can help inform urban planning internationally.

Are There Changes in Inequalities in Injuries? A Review of Evidence in the WHO European Region

“…After screening 1274 records a total of 27 studies [8,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56] met the criteria for inclusion, as shown in Figure 1. Seven were cross-country and 20 country-specific.…”

“…The second set of ten studies report changes within countries for all injuries aggregated ( n = 4) followed by road traffic injuries ( n = 4) and two studies on other injury mechanisms of interest [8,32,33,34,35,36,37,38,39,40]. They vary considerably as regards the research question and study group and reveal mixed results.…”

Do ‘environmental bads’ such as alcohol, fast food, tobacco, and gambling outlets cluster and co-locate in more deprived areas in Glasgow City, Scotland?

“…However, by including a large boundary surrounding the Glasgow City boundary, we have avoided potential edge effects. Our previous study used UK wide data and conducted a sensitivity analysis of Glasgow boundaries, finding the results were not sensitive to boundary definition ( Olsen et al, 2017 ).…”

“…The scan window used for the analysis surrounded that of Glasgow City, the boundary is supplied in Fig. 1 , and we chose this rectangular boundary as we have previously conducted sensitivity analysis of this window size ( Olsen et al, 2017 ).

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“…The cluster analysis approach applied within our paper has previously been used to detect geographic disparities in the incidence of disease cases, e.g. cancer ( Goungounga et al, 2016 ), tuberculosis ( Roth et al, 2016 ) and HIV ( Zhang et al, 2017 , Goungounga et al, 2016 , Roth et al, 2016 ) and to explore socio-economic distribution of road traffic accident cluster locations following the construction of a new motorway ( Olsen et al, 2017 ). Spatial cluster analysis has rarely been used to identify concentrations of retail outlets ( Han and Gorman, 2014 ) but lends itself well to this type of study for a number of reasons.…”