Motorcycles constitute the primary mode of transportation in Thailand. However, their prevalence has created an acute safety crisis, with motorcyclists representing over 70% of road fatalities. While previous studies have examined either injury severity or fault status in isolation, the potential interdependency between these outcomes remains poorly understood. This study addresses this gap by investigating motorcycle crash injury severity through both direct effects and indirect effects mediated through riders' at-fault status. This study examines motorcycle crash injury severity by considering both direct effects on outcomes and indirect effects mediated through riders' at-fault status. Analyses were conducted for three timeframes-2017-2018, 2019, and 2020-to capture potential temporal instability. A recursive bivariate modeling framework with random parameters was adopted to address unobserved heterogeneity and endogeneity between fault likelihood and crash severity outcomes, revealing key demographic, behavioral, and infrastructural predictors of fatal injuries. Findings indicate that younger riders, nighttime conditions, and high-risk behaviors (e.g., speeding, and alcohol use) increase the probability of being at fault. Meanwhile, factors such as being male, older, riding without a helmet, traveling against traffic, and riding at night significantly raise fatal injury risks. Although at-fault data provide valuable insights, they must be interpreted alongside roadway conditions, as Thailand's infrastructure offers limited protection for motorcyclists. Accordingly, this study recommends an integrated approach that combines improved infrastructure (e.g., motorcycle-friendly barriers and segregated lanes), robust education initiatives (targeting speed, helmet use, and alcohol awareness), and enhanced enforcement of traffic regulations. Implementing or enhancing licensing standards-such as a Graduated Licensing Scheme-can help curb risky behaviors and foster safer riding practices among young riders. These evidence-based recommendations can help policymakers develop more effective mitigation strategies to reduce the number of severe and fatal motorcyclerelated crashes.

Abstract Objective This study evaluated the effectiveness and potential safety benefits of a Rural Junction Active Warning System (RJAWS), which uses variable speed limit signs (VSLSs) to temporarily impose a reduced speed limit along the major road when another vehicle is approaching on the minor road or turning into the minor road from the far-side major leg. Methods The RJAWS was trialed at 4 3-leg rural junctions between 2-lane roads in South Australia. A quasi-experimental before–after analysis was conducted. The free-flow speed of vehicles along the junction major approaches was used as an indicator of the risk of a casualty crash with adjacent traffic. Events with activated and nonactivated VSLSs after the RJAWS installation were analyzed separately. Travel speed, speed limit compliance, and the relative risk of a casualty crash were compared. The potential risk of casualty crashes relative to traveling at the default speed limit was calculated based on a known relationship between travel speed and relative casualty risk for rural roads in South Australia. Results When the reduced speed limit signs are activated, the average travel speed along the major road is reduced between 11.3 and 22.1 km/h, with a consequent reduction of the expected average casualty risk between 42% and 65% compared to before the RJAWS installation. . Though compliance with the reduced posted speed limit was low, the RJAWS still proved effective in reducing travel speed because the majority of drivers traveled through the monitored junctions at speeds below the default speed limit when the sign was activated. Conclusions This evaluation indicated that the trialed RJAWS can potentially reduce the risk of fatal and serious injuries at junctions under conditions that may present the opportunity for an adjacent-direction collision with another vehicle. Extending the RJAWS installation to additional junctions is strongly suggested. Further monitoring is needed to determine whether safety benefits are sustained over the long term.

Using data from the Australian Naturalistic Driving Study (ANDS), this study examined patterns of secondary task engagement (e.g., mobile phone use, manipulating centre stack controls) during everyday driving trips to determine the type and duration of secondary task engaged in. Safety-related incidents associated with secondary task engagement were also examined. Results revealed that driver engagement in secondary tasks was frequent, with drivers engaging in one or more secondary tasks every 96 seconds, on average. However, drivers were more likely to initiate engagement in secondary tasks when the vehicle was stationary, suggesting that drivers do self-regulate the timing of task engagement to a certain degree. There was also evidence that drivers modified their engagement in a way suggestive of limiting their exposure to risk by engaging in some secondary tasks for shorter periods when the vehicle was moving compared to when it was stationary. Despite this, almost six percent of secondary tasks events were associated with a safety-related incident. The findings will be useful in targeting distraction countermeasures and policies and determining the effectiveness of these in managing driver distraction.

This study examined driver perceptions of safety at metro and regional intersections with different types of control. Data were collected using an on-line survey with 696 participants drawn from the Royal Automobile Association of South Australia's Member Panel. Results demonstrate a greater perception of safety associated with the use of round abouts, yet a reduced perception of safety associated with a lesser known Safe System aligned design of raised plateaus, suggesting a need for greater public awareness of the benefits of less well-known treatments.

Urban arterials and intersections account for a large proportion of high severity crashes in Australia and New Zealand, particularly involving vulnerable road users. Safety gains appear to be slower in these ‘mixed use’ environments than in other areas. Austroads commissioned research to help identify solutions that might be applied on mixed use arterial roads to improve safety through the provision of Safe System infrastructure. The project involved assessment of six case studies around Australia and New Zealand. Concept designs were developed for each of the routes based on analysis of safety issues and the likely safety benefits were assessed. This paper presents information on the safety solutions identified, as well as the broader issues that need to be considered when addressing safety on mixed use urban arterial roads.

Based on the Global Status Report on Road Safety 2018, the interrelationship of important road safety elements (such as Road Traffic Fatalities (RTFs), population, income levels, registered vehicles, law enforcement and others) of Thailand and other Asian countries could be achieved via a literature review and critical analysis. RTFs per 100,000 people had moderate correlations with motorization (registered vehicles per capita), while RTFs per 100,000 vehicles showed reasonable correlations with the number of registered vehicles per 100,000 people. When the number of registered vehicles per 100,000people increased, the RTFs per 100,000 vehicles decreased. The vehicles involved in RTFs in Thailand and other Asian countries were primarily 2/3-wheelers. As the proportion of 2/3- and 4-wheeled vehicles in Asian countries increased, the percentages of RTFs caused by 2/3- and 4-wheeled vehicles were enhanced. As the Gross National Incomes (GNIs) per capita of Asian countries enhanced, the road safety law enforcement was slightly better. Based on RTFs per 100,000 people, Thailand is one of the most hazardous countries for road transport in the world. In Thailand, a RTF (per 100,000 population) prediction model was derived using a limited time series with three RTF database sources. Motorization can potentially be used to predict the RTFs per 100,000 population in Thailand. In 2020, the anticipated RTFs per 100,000 people will be 29.4. That is greater than the target (18.0). Consequently, Thailand is unlikely to achieve its Sustainable Development Goals (SDGs) for road safety issues in the near future.

This study used data from the Australian Naturalistic Driving Study to study driver engagement in secondary tasks during every day driving and examine the role that various driver characteristics and driving context variables play in influencing the initiation of secondary tasks. Video from 186 randomly selected trips were viewed to identify a range of secondary tasks and to classify contextual variables at the point of task initiation (e.g. vehicle motion, weather, and light conditions). Results revealed that secondary task engagement when driving is highly prevalent, with drivers spending ∼45% of their driving time engaging in potentially distracting tasks. The results also showed that drivers make a number of strategic decisions regarding when to engage, such as waiting until the vehicle is stationary; however, they do not appear to consider some contextual factors that may impact risks, such as weather and light conditions. The findings will be useful in targeting distraction countermeasures and policies and determining the effectiveness of these in reducing driver distraction.

This report provides a compendium of knowledge on Safe System treatments and identifies real world experience in the practical application of solutions that can mitigate crash severity.

Distracted driving is widely recognised as a significant threat to the safety of all road users. Age-related declines in a range of sensory, cognitive and physical processes can, however, make older drivers particularly vulnerable to risks associated with distraction. While traditionally viewed as a younger driver issue, distracted driving among the older driver cohort is predicted to increase as future generations of older drivers drive more often, and for longer, and embrace technology in increasing numbers. This paper discusses current knowledge regarding why older drivers are particularly vulnerable to the effects of distracted driving and reviews recent research on older driver distraction engagement and its impact on their driving performance. Also presented, is an Australian case study of older driver secondary task engagement using data from the recently completed Australian Naturalistic Driving Study (ANDS). This case study examined patterns of secondary task engagement during everyday trips among 48 older (60+), middle-aged (43-49 years) and young (22-31 years) drivers. The findings suggest that Australian older drivers do engage in a large number of secondary tasks when driving; however, there is evidence that they self-regulate the type and timing of these tasks.

Modelling was conducted of road accident fatalities (RAFs) in Thailand and other Asian countries. Based on a cross-sectional analysis in 2013, an Asian model of predicted RAFs (per population) as a function of motorization (registered vehicles per capita) was developed. In addition, an Asian RAFs (per vehicles) prediction model was also developed. Increasing motorization corresponded with lower estimated RAFs per 10,000 vehicles. Also, the Thailand RAFs (per population) prediction model was achieved based on the limited time series analysis utilizing the 3 RAFs database sources. The motorization could potentially be adapted to estimate the RAFs per 100,000 population in Thailand Based on the Thailand RAFs prediction model and the predicted motorization in 2020, the estimated RAFs per 100,000 population will be 3 times greater than the targeted one. This means that Thailand will not be able to achieve the United Nations Sustainable Development Goal (SDG) for global road safety issues.

Road users such as pedestrians, cyclists and motorcyclists are highly susceptible to crash forces. Yet, while Safe System thinking accords susceptibility to crash forces and a forgiving system as focal principles, the greater vulnerability of these road users is barely recognised in many models of a Safe System. This is a concern of growing importance, given current efforts to increase usage of active travel modes and substantially rising injury rates among cyclists and motorcyclists. This paper explores a selection of research studies aiming to identify relevant factors behind traffic conflicts involving vulnerable road users, as a means to determine appropriate countermeasures particularly those involving infrastructure and vehicle technology. A better understanding of the contextual nature and causes of traffic conflict has much potential to contribute to Safe System thinking and conceptualisations, allowing them to extend beyond their traditional focus on susceptibility to crash forces and systems that are forgiving.

ABSTRACT Objectives: With the increasing popularity of cycling generally and availability of new bicycle child carriers, there is an emerging interest in the safety of child bicycle passengers and riders. However, very little is known about the nature and extent of injuries to child bicycle riders and passengers. The aim of this study was to enhance our understanding of child safety in bike transportation and to identify injury patterns and outcomes. Method: Analyses of Victorian hospital data (emergency department presentations and hospital admissions) were undertaken to describe and compare injury outcomes among children aged 0–3 years, 4–6 years, and 7–10 years on bicycles. Data over the 15-year period, July 1, 1999, to June 30, 2014, were examined. Results: A total of 17,859 emergency department presentations and 4,794 hospitalizations were reported for child cyclists under the age of 10 years. The rate of emergency department presentations and hospital admissions per 100,000 population decreased by 1.5% (−2.8 to −0.2%) and 5.0% (−6.5 to −3.4%), respectively. For emergency department presentations, the most commonly injured body parts included the head (34.9%), elbows and forearms (14.6%), and wrist and hands (16.3%). For hospital admissions, the head was again the most commonly injured body region (36.5%), followed by the elbow and forearm (26.7%) and shoulder and upper arm (9.1%). Comparisons of injured body regions between age groups revealed that children aged 3 and under were significantly more likely to sustain injuries to the head that required hospital admissions compared to older age groups. In contrast, older children, between the ages of 7 and 10 years, were significantly more likely to sustain injuries to either the arms, wrists, or hands. Further analysis of the nature of injury revealed that children aged 3 and under had a significantly higher number of open wound injuries compared to older children. Conclusion: This article provides an exploratory and broad overview of the magnitude and severity of injuries among child bike riders and passengers and highlights that younger children are more likely to sustain head injuries compared to older children. This is likely the result of very young children being passengers on bicycles who are constrained in a seat or trailer with little protection or opportunity to mitigate injuries. Highlights: • Analyses of injury data to understand the nature and extent of injuries to children on bikes as passengers and riders.• Child cyclist injuries as a significant safety issue within Victoria, Australia.• Young children aged 0–3 years experienced significantly more head injuries compared to older children.

The Safe System vision (known as Vision Zero, or Sustainable Safety in Europe) aspires to minimise death and serious injury as an outcome of road travel for all road users. The road engineering contribution to this vision focusses on impact elimination, or where this is not possible, on limiting kinetic energy passed to a road user in case of an impact. Impact kinetic energy is typically limited through vehicle speed management (e.g. speed limits, enforcement or geometric road design), as vehicle mass is difficult to effectively control by public road agencies. This paper reviews available international research on relationships between impact velocity change (delta-v), impact speeds and the probability of fatal and serious injury (MAIS3+) across a range of common crash scenarios. Based on the best identified relationships, and with assumption of equal mass and vehicle speeds, right--angle and head-on impact speeds of approximately 30km/h are likely to produce MASI3+ injury probability of approximately 10%, considered a critical threshold in Safe System discussions. For pedestrians, the threshold is likely to be even lower, approximately 20km/h. In rear-end crashes, the critical impact speed was found to be approximately 55km/h. Some practical applications of these findings are discussed. The paper discusses the assumptions and limitations behind the available evidence, and outlines the proposed research to strengthen it.

Background Typologies have been defined previously for pedestrian-vehicle interactions and are primarily based on retrospective analysis of crash data. The naturalistic driving study currently underway in Australia makes it possible to study pedestrian-vehicle interaction events that would not otherwise be identified in the crash data. This work evaluates the feasibility of using automated, manual, and semi-automated methods to identify pedestrian-vehicle interaction events. Methods Sensors and cameras were installed on the vehicles of volunteers in and around two major Australian cities which recorded their natural driving behaviour for 4 months. Forward video from select vehicles was reviewed independently by two reviewers to identify potential pedestrian-vehicle interaction events from which a typology of behaviours was formulated. These events served as the gold standard against which select automated and semi-automated methods of identification were assessed. Results A prototype typology of pedestrian-vehicle interaction events was formulated using naturalistic driving data and categorised in terms of risk of being struck. Some case scenarios will be discussed. The feasibility of using select automated, semi-automated, and manual methods to identify these events was also evaluated. Conclusions This work provides a first look at using Australian naturalistic driving data to study the interactions between vehicles and pedestrians. These findings will assist in the development of methods that can be used to most effectively answer research questions pertaining to interactions between vehicles and pedestrians as well as other vulnerable road users in the future.

Speed is recognised as a key contributor to crash likelihood and severity, and to road safety performance in general. Its fundamental role has been recognised by making Safe Speeds one of the four pillars of the Safe System. In this context, impact speeds above which humans are likely to sustain fatal injuries have been accepted as a reference in many Safe System infrastructure policy and planning discussions. To date, there have been no proposed relationships for impact speeds above which humans are likely to sustain fatal or serious (severe) injury, a more relevant Safe System measure. A research project on Safe System intersection design required a critical review of published literature on the relationship between impact speed and probability of injury. This has led to a number of questions being raised about the origins, accuracy and appropriateness of the currently accepted impact speed–fatality probability relationships (Wramborg 2005) in many policy documents. The literature review identified alternative, more recent and more precise relationships derived from the US crash reconstruction databases (NASS/CDS). The paper proposes for discussion a set of alternative relationships between vehicle impact speed and probability of MAIS3+ (fatal and serious) injury for selected common crash types. Proposed Safe System critical impact speed values are also proposed for use in road infrastructure assessment. The paper presents the methodology and assumptions used in developing these relationships. It identifies further research needed to confirm and refine these relationships. Such relationships would form valuable inputs into future road safety policies in Australia and New Zealand.