Stiffness-damping matching method of an ECAS system based on LQG control

A novel method of matching stiffness and continuous variable damping of an ECAS (electronically controlled air suspension) based on LQG (linear quadratic Gaussian) control was proposed to simultaneously improve the road-friendliness and ride comfort of a two-axle school bus. Taking account of the suspension nonlinearities and target-height-dependent variation in suspension characteristics, a stiffness model of the ECAS mounted on the drive axle of the bus was developed based on thermodynamics and the key parameters were obtained through field tests. By determining the proper range of the target height for the ECAS of the fully-loaded bus based on the design requirements of vehicle body bounce frequency, the control algorithm of the target suspension height (i.e., stiffness) was derived according to driving speed and road roughness. Taking account of the nonlinearities of a continuous variable semi-active damper, the damping force was obtained through the subtraction of the air spring force from the optimum integrated suspension force, which was calculated based on LQG control. Finally, a GA (genetic algorithm)-based matching method between stepped variable damping and stiffness was employed as a benchmark to evaluate the effectiveness of the LQG-based matching method. Simulation results indicate that compared with the GA-based matching method, both dynamic tire force and vehicle body vertical acceleration responses are markedly reduced around the vehicle body bounce frequency employing the LQG-based matching method, with peak values of the dynamic tire force PSD (power spectral density) decreased by 73.6%, 60.8% and 71.9% in the three cases, and corresponding reduction are 71.3%, 59.4% and 68.2% for the vehicle body vertical acceleration. A strong robustness to variation of driving speed and road roughness is also observed for the LQG-based matching method.

Concealed texting while driving : what are young people’s beliefs about this risky behaviour?

Making a conscious effort to hide the fact that one is texting while driving (i.e., concealed texting) is a deliberate and risky behaviour involving attention diverted from the road. As the most frequent users of text messaging services and mobile phones while driving, young people appear at heightened crash risk from engaging in this behaviour. First, several small focus group discussions (N = 12) were carried out to elicit the underlying salient beliefs regarding this behaviour, in accordance with the Theory of Planned Behaviour (TPB). Findings from these discussions, in conjunction with available prior evidence regarding general mobile phone use while driving, then informed questionnaire items that assessed young peoples’ beliefs regarding this behaviour, as well as intention to engage in this behaviour in the next week. In the questionnaire phase of the study, participants (N = 171) were aged 17–25 years, owned a mobile phone, and held a current driver’s licence. Results showed that there were significant differences between low and high intenders (to engage in concealed texting while driving) on the behavioural, normative, and control beliefs investigated. Specifically, high intenders were more likely to believe that concealed texting while driving would result in sharing information with others, using time effectively, and were less likely to think that free-flowing traffic would prevent their engagement in this behaviour. By targeting these beliefs, these findings may potentially inform the development of advertising and other public intervention strategies, aimed at ensuring young drivers reconsider their engagement in this risky behaviour.

Road safety knowledge exchange and capacity building between China and Australia

Road traffic injuries are one of the major public health burdens worldwide. The United Nations Decade of Action for Road Safety (2011-2020) implores all nations to work to reduce this burden. This decade represents a unique and historic period of time in the field of road safety. Information exchange and co-operation between nations is an important step in achieving the goal. The burden of road crashes, fatalities and injuries is not equally distributed. We know that low and middle-income countries experience the majority of the road trauma burden. Therefore it is imperative that these countries learn from the successes of others that have developed and implemented road safety laws, public education campaigns and countermeasures over many years and have achieved significant road trauma reductions as a result. China is one of the countries experiencing a large road trauma burden. Vulnerable road users such as pedestrians and cyclists make up a large proportion of fatalities and injuries in China. Speeding, impaired/drug driving, distracted driving, vehicle overloading, inadequate road infrastructure, limited use of safety restraints and helmets, and limited road safety training have all been identified as contributing to the problem. Some important steps have been taken to strengthen China’s approach, including increased penalties for drunk driving in May 2011 and increased attention to school bus safety in 2011/12. However, there is still a large amount of work needed to improve the current road safety position in China. This paper provides details of a program to assist with road safety knowledge exchange between China and Australia that was funded by the Australian Government which was undertaken in the latter part of 2012. The four month program provided the opportunity for the first author to work closely with key agencies in Australia that are responsible for policy development and implementation of a broad range of road safety initiatives. In doing so, an in-depth understanding was gained about key road safety strategies in Australia and processes for developing and implementing them. Insights were also gained into the mechanisms used for road safety policy development, implementation and evaluation in several Australian jurisdictions. Road traffic law and enforcement issues were explored with the relevant jurisdictional transport and police agencies to provide a greater understanding of how Chinese laws and practices could be enhanced. Working with agencies responsible for public education and awareness campaigns about road safety in Australia also provided relevant information about how to promote road safety at the broader community level in China. Finally, the program provided opportunities to work closely with several world-renowned Australian research centres and key expert researchers to enhance opportunities for ongoing road safety research in China. The overall program provided the opportunity for the first author to develop knowledge in key areas of road safety strategy development, implementation and management which are directly relevant to the current situation in China. This paper describes some main observations and findings from participation in the program.

Investigating the individual and organisational predictors of work-related driving crash involvement in Ethiopia

The rate of road traffic injury and death in Ethiopia is at a critical level when compared to rates in high-income countries. Considering the enormity of this issue, research is to identify groups of high-risk road users and the factors contributing to their crash involvement. This study focuses on work-related drivers. This study explores driving behaviour as a mediator of the relationship between organisational and individual attribute factors and self-reported crashes in a sample of 213 work-related drivers in Addis Ababa, Ethiopia. The hypothesised framework identifies driving behaviour as the most proximal determinant of self-reported crashes, and safety values, role overload and self-efficacy as antecedents of driving behaviour. With the exception of the relationship between self-efficacy and driving behaviour, all the hypothesised relationships were supported. We make recommendations for intervention approaches that are theoretically focused and sensitive to the cultural context.

Hospital outpatients' responses to taking medications with driving warnings

OBJECTIVE The study investigates the knowledge, intentions, and driving behavior of persons prescribed medications that display a warning about driving. It also examines their confidence that they can self-assess possible impairment, as is required by the Australian labeling system. METHOD We surveyed 358 outpatients in an Australian public hospital pharmacy, representing a well-advised group taking a range of medications including those displaying a warning label about driving. A brief telephone follow-up survey was conducted with a subgroup of the participants. RESULTS The sample had a median age of 53.2 years and was 53 percent male. Nearly three quarters (73.2%) had taken a potentially impairing class of medication and more than half (56.1%) had taken more than one such medication in the past 12 months. Knowledge of the potentially impairing effects of medication was relatively high for most items; however, participants underestimated the possibility of increased impairment from exceeding the prescribed dose and at commencing treatment. Participants' responses to the safety implications of taking drugs with the highest level of warning varied. Around two thirds (62.8%) indicated that they would consult a health practitioner for advice and around half would modify their driving in some way. However, one fifth (20.9%) would drive when the traffic was thought to be less heavy and over a third (37.7%) would modify their medication regime so that they could drive. The findings from the follow-up survey of a subsample taking target drugs at the time of the first interview were also of concern. Only just over half (51%) recalled seeing the warning label on their medications and, of this group, three quarters (78%) reported following the warning label advice. These findings indicated that there remains a large proportion of people who either did not notice or did not consider the warning when deciding whether to drive. There was a very high level of confidence in this group that they could determine whether they were personally affected by the medication, which may be a problem from a safety perspective. CONCLUSION This study involved persons who should have had a very high level of knowledge and awareness of medication warning labeling. Even in this group there was a lack of informed response to potential impairment. A review of the Australian warning system and wider dissemination of information on medication treatment effects would be useful. Clarifying the importance of potential risk in the general community context is recommended for consideration and further research.

Mathematical relationships for metal build-up on urban road surfaces based on traffic and land use characteristics

The study investigated the influence of traffic and land use parameters on metal build-up on urban road surfaces. Mathematical relationships were developed to predict metals originating from fuel combustion and vehicle wear. The analysis undertaken found that nickel and chromium originate from exhaust emissions, lead, copper and zinc from vehicle wear, cadmium from both exhaust and wear and manganese from geogenic sources. Land use does not demonstrate a clear pattern in relation to the metal build-up process, though its inherent characteristics such as traffic activities exert influence. The equation derived for fuel related metal load has high cross-validated coefficient of determination (Q2) and low Standard Error of Cross-Validation (SECV) values indicates that the model is reliable, while the equation derived for wear-related metal load has low Q2 and high SECV values suggesting its use only in preliminary investigations. Relative Prediction Error values for both equations are considered to be well within the error limits for a complex system such as an urban road surface. These equations will be beneficial for developing reliable stormwater treatment strategies in urban areas which specifically focus on mitigation of metal pollution.

Profile of women detected drink driving via Roadside Breath Testing (RBT) in Queensland, Australia, between 2000 and 2011

Background Drink driving among women is a growing problem in many motorised countries. While research has shown that male and female drink drivers differ on a number of characteristics, few studies have addressed the circumstances surrounding women’s drink driving offences specifically. Aim To add to previous research by comparing apprehension characteristics among men and women and to extend the understanding of the female drink driving problem by investigating the drink driving characteristics that are unique to women. Results The sample consisted of the 248,173 (21.5% women) drink drivers apprehended between 2000 and 2011 in Queensland, Australia. Gender comparisons showed that women were older, had lower levels of reoffending, and were more likely to be apprehended in Major Cities compared to men. Comparisons of age group and reoffending and non-reoffending among female drink drivers only revealed that higher BAC readings were more common among younger women. Moreover, a substantial minority (13.7%) of women aged 24 years or younger were apprehended with a BAC below0.05%, reflecting a breach of the zero tolerance BAC for provisional licence holders in Australia. Older women were more likely to be charged with a ‘failure to provide a test’ offence as a result of refusing to provide a breath or blood sample, indicating that drink driving is associated high levels of stigma for this group. Reoffending occurred among 16.2% of the female drink drivers and these drivers were more likely than non-reoffending drivers to record a mid to high range BAC, to be aged 30-39 or below 21years, and to be apprehended in Inner Regional or Remote locations. Conclusion Findings highlight the unique circumstances and divergent needs of female drink drivers compared to male drivers and for different groups of female drivers.

Processing biases towards gain-framed messages may lead reward sensitive individuals to adopt safer driving behaviours

Using Gray and McNaughton’s revised RST, this study investigated the extent to which the Behavioural Approach System (BAS) and the Fight-Flight-Freeze System (FFFS) influence the processing of gain-framed and loss-framed road safety messages and subsequent message acceptance. It was predicted that stronger BAS sensitivity and FFFS sensitivity would be associated with greater processing and acceptance of the gain-framed messages and loss-framed messages, respectively. Young drivers (N = 80, aged 17–25 years) viewed one of four road safety messages and completed a lexical decision task to assess message processing. Both self-report (e.g., Corr-Cooper RST-PQ) and behavioural measures (i.e., CARROT and Q-Task) were used to assess BAS and FFFS traits. Message acceptance was measured via self-report ratings of message effectiveness, behavioural intentions, attitudes and subsequent driving behaviour. The results are discussed in the context of the effect that differences in reward and punishment sensitivities may have on message processing and message acceptance.

Sustainability in post disaster road infrastructure recovery projects and asset management

Civil infrastructure and especially roads are being impacted with increasing frequency by flood, Tsunami, cyclone related natural and manmade disasters in the world. Responding to such events and in preparing for more regular and intense climate-change induced events in future, the road governing agencies are reviewing how postdisaster road infrastructure recovery projects are best planned and delivered. In particular, there is awareness that rebuilding such infrastructure require sustainable asset management strategies across economic, environmental and social dimensions. A comprehensive asset management framework for pre and post disaster situations can minimize negative impacts on our communities, economy and environment. This research paper is focused on post disaster management in road infrastructures and road infrastructure asset management strategies used by road authorities. Analyzing the implications of disruption to transport network and associated services is an important part of preparing local and regional responses to the impacts of disasters. This research paper will contribute to strategic infrastructure asset planning, management leading to safe, efficient and integrated transport system that supports sustainable economic, social and environmental outcomes. This paper also focuses on proper asset management, governance and engineering principles which should be followed and adopted in post disaster recovery projects to maximize sustainability in environmental, social and economic dimensions.

Groundwater table response to sea level rise and its impact on pavement structure

It has been predicted that sea level will rise about 0.8 m by 2100. Consequently, seawater can intrude into the coastal aquifers and change the level of groundwater table. A raise in groundwater table due to seawater intrusion threats the coastal infrastructure such as road pavements. The mechanical properties of subgrade materials will change due to elevated rise of groundwater table, leading to pavement weakening and decreasing the subgrade strength and stiffness. This paper presents an assessment of the vulnerability of subgrade in coastal areas to change in groundwater table due to sea-level rise. A simple bathtub approach is applied for estimating the groundwater level changes according to sea-level rise. Then the effect of groundwater level changes on the soil water content (SWC) of a single column of fine-sand soil is simulated using MIKE SHE. The impact of an increase in moisture content on subgrade strength/stiffness is assessed for a number of scenarios.

Environmental indicators for sustainable road development and operation

Road construction, maintenance and operation are activities that impact the environment by way of energy use, resource consumption and emission. Components such as construction material, transportation, street lighting, rolling resistance, traffic congestion during works, albedo and end-of-life processing impact the environment at different phases of the life of a road. With a view to promote sustainable development, a few sustainability rating schemes, e.g. Infrastructure Sustainability and Invest (Australia), Envision and Greenroads (USA), and CEEQUAL (UK) have been developed, that can assess road projects. These schemes address environmental areas such as: energy and emission, land, water, materials, discharges into surroundings, waste and ecology as factors for sustainable development. This paper assesses different rating schemes based on a defined comprehensive life cycle assessment (LCA) system boundary for road projects to identify different environmental indicators that address sustainable road development and operation. The findings indicate that new indicators are required to address different environmental components during the operation phase of roads.

Effect of joint mechanism on vehicle redirectional capability of water-filled road safety barrier systems

Portable water-filled barriers (PWFBs) are roadside appurtenances that prevent vehicles from penetrating into temporary construction zones on roadways. PWFBs are required to satisfy the strict regulations for vehicle re-direction in tests. However, many of the current PWFBs fail to re-direct the vehicle at high speeds due to the inability of the joints to provide appropriate stiffness. The joint mechanism hence plays a crucial role in the performance of a PWFB system at high speed impacts. This paper investigates the desired features of the joint mechanism in a PWFB system that can re-direct vehicles at high speeds, while limiting the lateral displacement to acceptable limits. A rectangular “wall” representative of a 30 m long barrier system was modeled and a novel method of joining adjacent road barriers was introduced through appropriate pin-joint connections. The impact response of the barrier “wall” and the vehicle was obtained and the results show that a rotational stiffness of 3000 kNm/rad at the joints seems to provide the desired features of the PWFB system to re-direct impacting vehicles and restrict the lateral deflection. These research findings will be useful to safety engineers and road barrier designers in developing a new generation of PWFBs for increased road safety.

Sustainability outcomes of infrastructure sustainability rating schemes for road projects

The construction and operation of infrastructure assets can have significant impact on society and the region. Using a sustainability assessment framework can be an effective means to build sustainability aspects into the design, construction and operation of infrastructure assets. The conventional evaluation processes and procedures for infrastructure projects do not necessarily measure the qualitative/quantitative effectiveness of all aspects of sustainability: environment, social wellbeing and economy. As a result, a few infrastructure sustainability rating schemes have been developed with a view to assess the level of sustainability attained in the infrastructure projects. These include: Infrastructure Sustainability (Australia); CEEQUAL (UK); and Envision (USA). In addition, road sector specific sustainability rating schemes such as Greenroads (USA) and Invest (Australia) have also been developed. These schemes address several aspects of sustainability with varying emphasis (weightings) on areas such as: use of resources; emission, pollution and waste; ecology; people and place; management and governance; and innovation. The attainment of sustainability of an infrastructure project depends largely on addressing the whole-of-life environmental issues. This study has analysed the rating schemes’ coverage of different environmental components for the road infrastructure under the five phases of a project: material, construction, use, maintenance and end-of-life. This is based on a comprehensive life cycle assessment (LCA) system boundary. The findings indicate that there is a need for the schemes to consider key (high impact) life cycle environmental components such as traffic congestion during construction, rolling resistance due to surface roughness and structural stiffness of the pavement, albedo, lighting, and end-of-life management (recycling) to deliver sustainable road projects.

Enabling safe autonomous driving in real-world city traffic using multiple criteria decision making

This paper addresses the topic of real-time decision making for autonomous city vehicles, i.e., the autonomous vehicles' ability to make appropriate driving decisions in city road traffic situations. The paper explains the overall controls system architecture, the decision making task decomposition, and focuses on how Multiple Criteria Decision Making (MCDM) is used in the process of selecting the most appropriate driving maneuver from the set of feasible ones. Experimental tests show that MCDM is suitable for this new application area.

Towards increased road safety : real-time decision making for driverless city vehicles

This work elaborates on the topic of decision making for driverless city vehicles, particularly focusing on the aspects on how to develop a reliable approach which meets the requirements of safe city traffic. Decision making in this context refers to the problem of identifying the most appropriate driving maneuver to be performed in a given traffic situation. The overall decision making problem is decomposed into two consecutive stages. The first stage is safety-crucial, representing the decision regarding the set of feasible driving maneuvers. The second stage represents the decision regarding the most appropriate driving maneuver from the set of feasible ones. The developed decision making approach has been implemented in C++ and initially tested in a 3D simulation environment and, thereafter, in real-world experiments. The real-world experiments also included the integration of wireless communication between vehicles.