Christine Mulvihill

Detection of emergency vehicles: driver responses to advance warning in a driving simulator.

Objective: This research evaluated the effects of an advance warning device (AWD) on the safety of driver interactions with emergency vehicles (EVs). The AWD was intended to provide drivers with advance warning of an approaching on-call EV via visual and auditory warnings when the EV was within a 300- to 400-m radius. Background: Research suggests that drivers can experience difficulty accurately detecting the distance and direction of approaching on-call EV. In-vehicle technology has not previously been explored as a means of overcoming the limitations of existing EV lights and sirens and improving driver detection of EV. Method: An experimental study using an advanced driving simulator examined the effects of the AWD on driving performance in a range of circumstances in which real-world EV crashes and near-misses commonly occur. Each event contained a combination of scenario type (adjacent lane, turning across, car following) and warning condition (control, standard, advance). Results: Data from 22 participants were collected, including measures of speed, braking, and visual scanning. For adjacent-lane and turning-across events, the AWD was associated primarily with reductions in mean speed. The AWD resulted in an earlier lane change to clear a path for the EV in the car-following event. Conclusion: The reduction in speed observed was a positive finding, given the relationship between impact speed and injury severity. Response priming emerged as the mechanism underpinning these effects. Application: Response priming may result in safety benefits in other settings when an advisory warning is presented before the threat can be perceived.

More than Meets the Eye: Using Cognitive Work Analysis to Identify Design Requirements for Future Rail Level Crossing Systems

An increasing intensity of operations means that the longstanding safety issue of rail level crossings is likely to become worse in the transport systems of the future. It has been suggested that the failure to prevent collisions may be, in part, due to a lack of systems thinking during design, crash analysis, and countermeasure development. This paper presents a systems analysis of current active rail level crossing systems in Victoria, Australia that was undertaken to identify design requirements to improve safety in future rail level crossing environments. Cognitive work analysis was used to analyse rail level crossing systems using data derived from a range of activities. Overall the analysis identified a range of instances where modification or redesign in line with systems thinking could potentially improve behaviour and safety. A notable finding is that there are opportunities for redesign outside of the physical rail level crossing infrastructure, including improved data systems, in-vehicle warnings and modifications to design processes, standards and guidelines. The implications for future rail level crossing systems are discussed.

Simulating the Dynamic Effect of Land Use and Transport Policies on the Health of Populations

OBJECTIVES We identified the features of a land use-transportation system that optimizes the health and well-being of the population. METHODS We developed a quantitative system dynamics model to represent relationships among land use, transport, economic development, and population health. Simulation experiments were conducted over a 10-year simulation period to compare the effect of different baseline conditions and land use-transport policies on the number of motor vehicle crash deaths and disability-adjusted life years lost. RESULTS Optimal reduction in the public health burden attributable to land transport was demonstrated when transport safety risk reduction policies were combined with land use and transport polices that minimized reliance on individual motorized transport and maximized use of active transport modes. The models results were particularly sensitive to the level of development that characterized each city at the start of the simulation period. CONCLUSIONS Local, national, and international decision-makers are encouraged to address transport, land use, and health as an integrated whole to achieve the desired societal benefits of traffic safety, population health, and social equity.

Using the decision ladder to understand road user decision making at actively controlled rail level crossings.

Rail level crossings (RLXs) represent a key strategic risk for railways worldwide. Despite enforcement and engineering countermeasures, user behaviour at RLXs can often confound expectations and erode safety. Research in this area is limited by a relative absence of insights into actual decision making processes and a focus on only a subset of road user types. One-hundred and sixty-six road users (drivers, motorcyclists, cyclists and pedestrians) completed a diary entry for each of 457 naturalistic encounters with RLXs when a train was approaching. The final eligible sample comprised 94 participants and 248 encounters at actively controlled crossings where a violation of the active warnings was possible. The diary incorporated Critical Decision Method probe questions, which enabled user responses to be mapped onto Rasmussens decision ladder. Twelve percent of crossing events were non-compliant. The underlying decision making was compared to compliant events and a reference decision model to reveal important differences in the structure and type of decision making within and between road user groups. The findings show that engineering countermeasures intended to improve decision making (e.g. flashing lights), may have the opposite effect for some users because the system permits a high level of flexibility for circumvention. Non-motorised users were more likely to access information outside of the warning signals because of their ability to achieve greater proximity to the train tracks and the train itself. The major conundrum in resolving these issues is whether to restrict the amount of time and information available to users so that it cannot be used for circumventing the system or provide more information to help users make safe decisions.

Applying the prompt questions from the Cognitive Work Analysis Design Toolkit: a demonstration in rail level crossing design

ABSTRACT Accidents at rail level crossings (RLXs) represent an important public safety concern. Traditional approaches to RLX safety have focused on the implementation of technology such as warnings and barriers to control road user behaviour. However, as RLXs are complex sociotechnical systems, there is a need to apply systems-based approaches to analysis and design within this domain. This will enable road and rail stakeholders to develop innovative design solutions which are appropriate for the complexity of the domain, including adaptability to future changes in a dynamic transport environment. This paper describes the use of one aspect of a systems thinking-based design toolkit to prompt design insights following the application of the cognitive work analysis framework to RLXs. The process resulted in the identification of design insights for use in a participatory design process and supported the research team to consider the principles of sociotechnical systems theory.

Evaluation of novel urban rail level crossing designs using driving simulation

Rail level crossings (RLXs) are a public safety concern internationally. The design of the RLX environment has been implicated in many recent crashes. In this study we evaluated three novel RLX design concepts using a driving simulator. Participants completed four drives, each incorporating one of the RLX designs (one baseline and three novel designs) in both train coming and train not coming mode. Measures of speed and braking on approach were analyzed, along with subjective measures of workload and usability. Superior driving behavior and subjective ratings were achieved for a design that incorporated an in-vehicle device while the lowest subjective ratings were given in relation to a shared space design that incorporated a simplified crossing environment and sharing of the road environment between motorized and non-motorized users. The implications for RLX safety are discussed.