Assessment of the Effects of Road Geometry on Irish Accident Rates and Driving Behaviour

The following thesis documents the work carried out throughout two main experiments. The first experiment analyses driver crash data and extracts from it accidents that may have occurred as a result of road segments with bad geometry. A visualisation and analysis of this crash data is presented to better determine the relationship ‘if any’ between road geometry and accident points. The second experiment then examines driver behaviour on road segments that also contain bad bends using a purpose built driving simulator. This experiment is ‘driver centric’ as it measures behaviour such as eye movement. Both experiments examine contrasting Irish roadways with an aim to better understand the driver when negotiating various geometries. Findings from the crash data analysis initially show the majority of accidents occurring on straight segments of the road types examined. However, when these accident frequencies are normalised against the percentage of road that consist of straights and bends, interesting signals appear on road types that combine sharp bends with higher road speed limits. Results from driver eye behaviour analysis show drivers fixating on regions of the road based on visible geometry or available sight distance. For example, drivers fixate on areas at the road bend while negotiating sharp bends and fixate further on or above the road surface when traversing straight segments