The aim of this report was to assess the respective roles of inadvertent errors and unsafe driver behaviour at intersections and to identify road design features which aim to minimise the occurrence of inappropriate speeds and other errors and their consequences. This study was conducted as part of the Curtin-Monash University Accident Research Centre Baseline Research program and consisted of two literature searches that were supplemented by a detailed examination of intersection crash data of serious injury and fatal casualties from Western Australia (WA). First, a review of the published literature was conducted on driver behaviour and source of errors at intersections. It was anticipated that the findings from the literature search would be matched against the types of intersection crashes that occurred in WA from 2004 to 2009 as indicated by the crash investigation data. The analysis of serious casualty crashes (fatalities and hospitalisations) at intersections in WA revealed the majority of intersection crashes occurred in metropolitan areas. A similar proportion of serious casualty crashes occurred at sign control intersections (35%) and signal control intersections (35%), with fewer casualties occurring at uncontrolled intersections (30%). Overall, the most common crash type was right-angle crashes accounting for 38% of all serious casualty crashes. Right-angle crashes typically occurred at sign control intersections. The second most frequent crash type was right-through crashes (cross traffic collisions) which occur when a vehicle completes a right hand turn in front of an oncoming vehicle. These crashes predominantly occurred at signal-controlled intersections rather than sign-controlled or uncontrolled intersections. In contrast to right-angle crashes and right-through crashes, the majority of crashes at roundabouts were hit object crashes. A review of the literature found a variety of sources of error specific to each crash type. For example, right-angle crashes at signal-controlled intersections often occur because drivers fail to stop at a red light and engage in red-light running behaviour (Wang & AdelAty, 2007). Conversely, right-angle crashes at sign controlled intersections have been attributed to poor visual scanning behaviour (Bao & Boyle, 2009), and failure to yield right of way (particularly for older drivers) (Preusser, Williams, Ferguson, Ulmer & Weinstein, 1998). Although roundabouts are known to reduce the number of rear-end crashes, the review identified the following sources of driver error: knowledge of priority rules (Räsänen & Summala, 2000), driver entry speed to the roundabout (Arndt & Troutbeck, 1998) and driver attention and visual search difficulties (Summala, Pasanen, Räsänen, & Sievanen, 1996). There were a limited number of studies specifically related to crashes at intersections in Australia (Baldock, 2005; Cameron, in press; Corben, Ambrose, & Foong, 1990). General road user characteristics that are pertinent to all intersection control types include speed, driver intoxication, driver fatigue and driver experience. The second stage of the study included a literature review of available countermeasures to focus on road design features to reduce driver error and the consequence of these errors at intersections. A list of potential countermeasures identified from the literature is discussed in relation to each intersection control type. Finally, a fault tree analysis of the Australian National Crash In-depth Study crash investigation database is provided to outline the causal factors of an intersection crash. (Author/publisher)
Abstract