Beware the intersection: A study of road collisions in Dublin shows where and when crashes are more likely to occur.
The analysis of 10,000 road-traffic collisions over six years has found that a spot near the Naas Road, the point where the M11 and the M50 meet near Bray, and the M50 near Clondalkin are areas where “clusters” of crashes occur, in addition to the city centre.
There is an increased likelihood of serious accidents at night-time on bendy roads, and heavy traffic is more likely to lead to a minor collision, rather than a serious one.
The ‘Analysis of Traffic Collisions in Dublin Using GIS-Based System’ was carried out by Jagteshwar Singh and Niamh O’Reilly, both of the Dublin Institute of Technology. It reviewed traffic collisions in the Greater Dublin region from 2006 to 2012. They then used GIS to identify hotspots and trends in when and where accidents — both severe and minor — occurred.
The data, from the Road Safety Authority (RSA), showed that 9,578 road collision were recorded by gardai in Dublin across the study period, with the researchers then exploring other factors, including traffic characteristics and infrastructure.
According to the study: “A total of 693 severe collisions occurred in Dublin, from 2006-12, out of which only 72 were found to show significant amount of clustering in space-time.”
These occurred on the Naas road, near Saggart ,“especially where R120 joins N7 motorway”, during the early hours of the morning (1am-4 am); near Bray, at the point of confluence of M50 and M11, between 8-11 pm; and “significant clustering of collisions near Clondalkin, on the M50 motorway, between 9-12 am”.
As for Dublin city centre, a majority of collisions occur during the busy daytime hours, between 2pm and 7pm.
On bends, severe collisions are most common during the night, especially from 1am-5 am, when about 26.7% of them took place; during the same 1am-5am time period, just 12.5% of all the severe collisions occurred, and only about 4% of minor collisions.
Single-vehicle collisions are more prevalent during the night, from 11pm to 7am on bendy road sections, indicating a “critical combination” of night-time and sharp-road curvature. “It might suggest the prevalence of drunk-driving, driver fatigue, or overspeeding during night-time, leading to loss of control at road bends,” it said.
As for speed, collision rates are highest during the day (7am-7pm) in the speed range of 40kmph-50kmph, whereas, at night (7pm-7am), they are highest at speeds of 55kmph-60kmph and also at 80kmph.
Traffic volume has no significant relation to frequency of severe collisions, whereas the greater the traffic volume, the greater the number of minor crashes.
As for where some of these accidents occur, “collisions are predisposed to occur near the intersection, with high values in the range 0-15m [from it]. However, single-vehicle collisions are more likely to occur away from the intersection, in the distance range 50-100m and beyond.
“The findings suggest that 37.5% of rear-end, severe collisions occur at a distance of between 15m and 30m from the intersection,” with the majority of head-on collisions at the intersection.
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