Evaluation of alternative intersection treatments at rural crossroads using simulation software

Objective: Rural roads are characterised by hazardous roadsides and suboptimal geometry, yet allow for high travel speeds and unfavourable impact angles. In Victoria, 25% of persons seriously injured and 52% of fatalities occur on rural roads, with 30% occurring at intersections (Transport Accident Commision, 2016; Victorian Parliament Road Safety Committee 2002). In the USA, almost twice the number of traffic fatalities occur in rural areas than in urban areas, whilst accounting for less than half of all vehicle miles travelled and 21% of the population (NHTSA 2002). The choice of safety countermeasure is therefore paramount. Simulation software provides a cost-effective means of analysing alternative intersection treatments with a view to identifying their effectiveness in mitigating crashes. The aim of this research was to assess the safety benefits of four alternative intersection treatments using in-depth crash data with an advanced crash reconstruction process. Method: Using a single serious injury real-world crash from the MUARC Enhanced Crash Investigation Study (ECIS, Fitzharris et al., 2015) and crash reconstruction software, an exemplar rural crash was reconstructed and validated against real-world data. The crash involved a passenger vehicle (EuroNCAP 5*) approaching from a minor road and failing to yield at a ‘give-way’ sign; the posted speed limit was 80 km/h. The vehicle was struck on the right/driver side by a rigid truck (B-vehicle; 1990) travelling on the major approach (100 km/h). The driver of the case vehicle was seriously injured. Four alternative intersection treatments appropriate for the crash site were constructed in CAD software (Rhinoceros V5): roundabout; rumble strips; a reduced speed limit and the combination of lower speed limit and rumbles to determine the reduction in crash forces in the presence of the countermeasures. Results: The hypothetical scenarios demonstrate substantial reductions in impact force and different points of impact, resulting in a significantly lower injury severity for the struck driver. Speed limit reduction to 80 km/h on the main approach (from 100 km/h) in combination with rumble strips on both intersection approaches had the most favorable outcome with the crash avoided entirely, assuming speed compliance. Discussion: The findings have implications for understanding the role of speed in crashes, and hence the design of effective countermeasures. Simulation software, validated using real-world data, provides a cost effective means of evaluating alternative intersection treatments for rural intersections. Scaled up, implementing these treatments would have significant safety benefits and reduce the road trauma currently associated with rural roads

What drivers do while speeding: examining the associations between speeding and driver distraction through the Enhanced Crash Investigation Study protocol [Abstract]

This paper represents an exploratory analysis to assess the feasibility of assessing the relationship between driver speed and engagement in potentially distracting behaviours. Control data from the ECIS project are examined. These data include both objective speed measurements recorded via laser camera positioned at ECIS case-vehicle crash locations as well as retrospective self-reported driving behaviours from drivers recorded at these sites. Exploratory analysis suggests that the activities reported by drivers with recorded speeds above the limit may differ from the activities reported by those recorded on or below the limit

The MUARC-TAC enhanced crash investigation study: study update, analysis of crash types and contributing factors [Abstract]

This paper presents an update of the Monash University Accident Research Centre (MUARC) – Transport Accident Commission (TAC) Enhanced Crash Investigation Study (ECIS) as well as an exploration of the characteristics of injured drivers, crash types and factors implicated in crash occurrence. Three configurations are of particularly high frequency and severity, whilst crashes involving young and older drivers are different in nature and have different contributing factors. Fatigue, driver error, and pre-crash driver blackouts due to medical conditions were prominent contributing factors. Injury severity would be significantly lower in 32% of cases if either front or side airbags were fitted. The findings point to key risk factors that can be addressed in road safety strategies

The MUARC-TAC enhanced crash investigation study: a platform to understand the causes and consequences of serious injury crashes.

Background: In recognising the consequences of serious injury crashes, the Transport Accident Commission (TAC) commissioned Monash University Accident Research Centre (MUARC) to undertake the Enhanced Crash Investigation Study (ECIS). This paper describes the program components, seven key research questions and technical innovations used in the study. We describe the information collected and outline a ‘Safe Systems Failure Analysis’ used for each case. Project Method: Participants in ECIS include drivers aged 18 years and older seriously injured in crashes on public Victorian roads. Drivers are recruited whilst inpatients at a major trauma hospital and where possible interviews conducted. The ECIS team inspects their crashed vehicle and critically analyses the crash environment. Event Data Recorder (EDR, black-box) data is acquired from vehicles where possible and crash reconstructions are undertaken. Each case is submitted to an internal panel review with a sub-sample of cases presented to external panels throughout Victoria. This process leads to each case being submitted to a Safe Systems Failure Analysis where contributing factors and countermeasures are identified by a broad group of stakeholders. The ECIS control arm permits examination of the relationship between certain factors, such as speed and crash occurrence. Results and Discussion: In addition to describing the study, we provide an example of how the identification of crash factors, using a Safe Systems paradigm based on real-world serious injury crashes, can lead to the identification of targeted countermeasures, each with an identified policy action. Implications: This paper will demonstrate a method for creating a robust evidence base upon which government road safety policy can be built. By scaling up individual crash findings to the broader crash population, countermeasures and associated policy actions can be appropriately prioritised

Assessing the Compatibility Between Australian Roads and New Vehicle Technologies

The promotion of driver assist technologies are based on a) the impressive effectiveness rates these technologies boast and b) the premise that the technologies will be capable of mitigating technology-sensitive crash types independent of where vehicles fitted with these technologies are driven. Not all roads in Australia, however, have technology-supportive road infrastructure. This research set out to identify how much of the Australian road network is not fitted with the infrastructure that is required for supporting technologies including Lane Keep Assist (LKA), Autonomous Emergency Braking (AEB) and Intelligent Speed Assist (ISA) and the implications of this on road safety

The Importance of Adopting a Safe System Approach—Translation of Principles into Practical Solutions

The 1990s saw the emergence of the Swedish Vision Zero and the Dutch Sustainable Safety philosophies on road safety. At the time, both were considered somewhat radical and ambitious departures from the status quo. The principles that underpinned both the Dutch and Swedish philosophies were combined into an internationalized form, now known more widely as the Safe System. The Safe System came to attention early in the 2000s, when formally adopted by a number of countries committed to preventing severe road trauma. The Safe System defines a new way of thinking about road safety compared with what had commonly been used around the world in the decades before its conception. The Safe System strives to eliminate death and severe injury from the world’s roads. It also underlines the importance of the safe management of kinetic energy and system-based design that seeks to ensure that crashes are prevented or, at worst, crash forces fall within the threshold of human tolerance to severe injury. Once this thinking is embraced by the system designer, new solutions begin to emerge, and existing designs can be seen in a different, more insightful light. The process of transitioning to the ambitious, ethically based philosophy of the Safe System, as a means of addressing the risks of using our roads, has not happened smoothly or quickly. Practitioners have had difficulty in translating the philosophy and principles of the Safe System into practice. It is hoped that by providing examples of the differences in decisions made under Safe System principles when designing and operating roads, large gains will be made toward the lasting elimination of road trauma. A major focus of the discussion is on the Safe System-aligned design of infrastructure, coupled with vehicle operating speeds, while also recognizing the contributions to risk reduction that can come from improved human performance and the evolving safety features and technologies of modern vehicles

Quantifying the foregone benefits of intelligent speed assist due to the limited availability of speed signs across three Australian states

By being able to communicate the speed limit to drivers using speed sign recognition cameras, Intelligent Speed Assist (ISA) is expected to bring significant road safety gains through increased speed compliance. In the absence of complete digital speed maps and due to limited cellular connectivity throughout Australia, this study estimated the forgone savings of ISA in the event that speed signs are solely relied upon for optimal advisory ISA function. First, speed-related fatalities and serious injuries (FSI) in the Australian states of Victoria, South Australia, and Queensland (2013–2018) were identified, and published effectiveness estimates of ISA were applied to determine the potential benefits of ISA. Subsequently, taking into account speed sign presence across the three states, the forgone savings of ISA were estimated as FSI that would not be prevented due to absent speed signage. Annually, 27–35% of speed-related FSI in each state are unlikely to be prevented by ISA because speed sign infrastructure is absent, equating to economic losses of between AUD 62 and 153 million. Despite a number of assumptions being made regarding ISA fitment and driver acceptance of the technology, conservative estimates suggest that the benefits of speed signs placed consistently across road classes and remoteness levels would far outweigh the costs expected from the absence of speed signs. The development and utilisation of a methodology for estimating the foregone benefits of ISA due to suboptimal road infrastructure constitutes a novel contribution to research. This work provides a means of identifying where infrastructure investments should be targeted to capitalise on benefits offered by advanced driver assist technologies

Parents’ willingness to allow their unaccompanied children to use emerging and future travel modes

This study investigated parents’ willingness to allow their unaccompanied child(ren) to use emerging and future travel modes (e.g., rideshare vehicles and automated vehicles). An online survey was completed by 631 Australian respondents (M = 39.2 years, SD = 10.5 years, Male: 36.6%) who reported that they currently lived with one or more children (17 or below). Approximately one-third (37.9%) of the respondents reported a willingness to allow their child to use a rideshare vehicle alone and more than half of the respondents (57.2%) reported a willingness to allow their child to use an automated vehicle alone. Respondents who expressed willingness to allow their child to use a rideshare vehicle alone were more likely to express a willingness to use an automated vehicle alone (79.1%) compared to respondents who were unwilling to use a rideshare vehicle (43.9%), χ2(1) = 75.158, p < 0.001, Phi = 0.345. Two separate logistic regression models revealed key similarities and differences related to respondents’ willingness to allow their unaccompanied child to use both transport modes. Respondents’ willingness to allow their unaccompanied child to use a rideshare vehicle was significantly related to their previous use of a rideshare vehicle with their child, having an optimistic view of technology, annual mileage, their aberrant driving behaviours, and their desire for route-control and assurance features within the rideshare vehicle, χ2(7) = 159.594, p < 0.001. Respondents’ willingness to allow their child to use an automated vehicle alone was significantly related to awareness of automated vehicles, education level, positive views towards technology, seeing technology to be innovative, and requirements for route control features within the automated vehicle, χ2(6) = 113.325, p < 0.001. Despite the potential for emerging or future travel modes to provide additional personal transportation options, these results suggest that Australian parents are unwilling to allow their unaccompanied child to use these modes of transport. These findings will have significant implications for transport planning, particularly in growing communities where pressures on parents to transport their child(ren) to activities and events with minimal adult supervision is increasing