Response-based methods to measure road surface irregularity: a state-of-the-art review

"jats:sec" "jats:title"Purpose"/jats:title" "jats:p"With the development of smart technologies, Internet of Things and inexpensive onboard sensors, many response-based methods to evaluate road surface conditions have emerged in the recent decade. Various techniques and systems have been developed to measure road profiles and detect road anomalies for multiple purposes such as expedient maintenance of pavements and adaptive control of vehicle dynamics to improve ride comfort and ride handling. A holistic review of studies into modern response-based techniques for road pavement applications is found to be lacking. Herein, the focus of this article is threefold: to provide an overview of the state-of-the-art response-based methods, to highlight key differences between methods and thereby to propose key focus areas for future research."/jats:p" "/jats:sec" "jats:sec" "jats:title"Methods"/jats:title" "jats:p"Available articles regarding response-based methods to measure road surface condition were collected mainly from “Scopus” database and partially from “Google Scholar”. The search period is limited to the recent 15 years. Among the 130 reviewed documents, 37% are for road profile reconstruction, 39% for pothole detection and the remaining 24% for roughness index estimation."/jats:p" "/jats:sec" "jats:sec" "jats:title"Results"/jats:title" "jats:p"The results show that machine-learning techniques/data-driven methods have been used intensively with promising results but the disadvantages on data dependence have limited its application in some instances as compared to analytical/data processing methods. Recent algorithms to reconstruct/estimate road profiles are based mainly on passive suspension and quarter-vehicle-model, utilise fewer key parameters, being independent on speed variation and less computation for real-time/online applications. On the other hand, algorithms for pothole detection and road roughness index estimation are increasingly focusing on GPS accuracy, data aggregation and crowdsourcing platform for large-scale application. However, a novel and comprehensive system that is comparable to existing International Roughness Index and conventional Pavement Management System is still lacking."/jats:p" "/jats:sec Document type: Articl

Platooning of Autonomous Public Transport Vehicles: The Influence of Ride Comfort on Travel Delay

The development of advanced technologies has led to the emergence of autonomous vehicles. Herein, autonomous public transport (APT) systems equipped with prioritization measures are being designed to operate at ever faster speeds compared to conventional buses. Innovative APT systems are configured to accommodate prevailing passenger demand for peak as well as non-peak periods, by electronic coupling and decoupling of platooned units along travel corridors, such as the dynamic autonomous road transit (DART) system being researched in Singapore. However, there is always the trade-off between high vehicle speed versus passenger ride comfort, especially lateral ride comfort. This study analyses a new APT system within the urban context and evaluates its performance using microscopic traffic simulation. The platooning protocol of autonomous vehicles was first developed for simulating the coupling/decoupling process. Platooning performance was then simulated on VISSIM platform for various scenarios to compare the performance of DART platooning under several ride comfort levels: three bus comfort and two railway criteria. The study revealed that it is feasible to operate the DART system following the bus standing comfort criterion (ay = 1.5 m/s2) without any significant impact on system travel time. For the DART system operating to maintain a ride comfort of the high-speed train (HST) and light rail transit (LRT), the delay can constitute up to ≈ 10% and ≈ 5% of travel time, respectively. This investigation is crucial for the system delay management towards precisely designed service frequency and improved passenger ride comfort

Response-based methods to measure road surface irregularity : a state-of-the-art review

Purpose: With the development of smart technologies, Internet of Things and inexpensive onboard sensors, many response-based methods to evaluate road surface conditions have emerged in the recent decade. Various techniques and systems have been developed to measure road profiles and detect road anomalies for multiple purposes such as expedient maintenance of pavements and adaptive control of vehicle dynamics to improve ride comfort and ride handling. A holistic review of studies into modern response-based techniques for road pavement applications is found to be lacking. Herein, the focus of this article is threefold: to provide an overview of the state-of-the-art response-based methods, to highlight key differences between methods and thereby to propose key focus areas for future research. Methods: Available articles regarding response-based methods to measure road surface condition were collected mainly from “Scopus” database and partially from “Google Scholar”. The search period is limited to the recent 15 years. Among the 130 reviewed documents, 37% are for road profile reconstruction, 39% for pothole detection and the remaining 24% for roughness index estimation. Results: The results show that machine-learning techniques/data-driven methods have been used intensively with promising results but the disadvantages on data dependence have limited its application in some instances as compared to analytical/data processing methods. Recent algorithms to reconstruct/estimate road profiles are based mainly on passive suspension and quarter-vehicle-model, utilise fewer key parameters, being independent on speed variation and less computation for real-time/online applications. On the other hand, algorithms for pothole detection and road roughness index estimation are increasingly focusing on GPS accuracy, data aggregation and crowdsourcing platform for large-scale application. However, a novel and comprehensive system that is comparable to existing International Roughness Index and conventional Pavement Management System is still lacking.NRF (Natl Research Foundation, S’pore)Published versio

The effects of unhealthy lifestyle behaviours on risky riding behaviours – A study on app-based motorcycle taxi riders in Vietnam

Introduction: In developing countries, traditional motorcycle taxis are operated as a type of public transport mode. Recently, the development of mobile technology has enabled this transport mode to become an app-based motorcycle taxi service, leading to a rapid increase in travel demand. However, the emergence of app-based motorcycle taxi riders is considered to contribute directly and indirectly to the high proportion of road traffic crashes through their risky riding behaviours. The associations between unhealthy habits such as smoking, drink riding and other risky behaviours among motorcyclists have received less attention. Therefore, the aim of this study is to explore the effect of unhealthy lifestyle behaviours on risky riding behaviours among app-based motorcycle taxi riders. This study also explores the prevalence of risky riding behaviours and their associations. Methods: An online survey and field surveys were carried out to obtain information about app-based motorcycle taxi riders’ demographics, work patterns and risky riding behaviours. More than 600 riders (mean age = 25.74 years, SD = 7.3), who were working in the three largest cities in Vietnam, completed a structured questionnaire. Results: Binary logistic regression modelling showed that riders who regularly smoked and drunk alcohol were more likely to engage in the risky behaviours of smoking while riding and drink riding (Adj. OR = 18.61, 95%CI, p < 0.001 and Adj. OR = 9.02, 95%CI, p < 0.01 respectively). The results also indicated that those who sometimes smoked cigarettes were more likely not to wear helmets when riding (Adj. OR = 2.55, p < 0.01). While smoking habits were associated with smoking while riding and not wearing a helmet, most surveyed risky riding behaviours were associated with drinking habits. Significant associations between smoke/drink riding and all other risky riding behaviours were also found in this study. Conclusion: A better understanding of these relationships will help authorities and ride-hailing firms to improve safe riding behaviours among app-based motorcycle taxi riders.</p

Insight into the lateral ride discomfort thresholds of young-adult bus passengers at multiple postures : case of Singapore

Ride comfort is an important serviceability attribute for bus passengers, of which bus operating under the influence of road layout in urban roads is a prominent contributory factor. Passenger posture is another influencing factor that has not yet been investigated comprehensively. In this case study, ride comfort from road-induced lateral acceleration and lateral jerk was assessed by correlating subjective evaluation with bus operation performance parameters as well as road layout in Singapore. In the first bus run, a sample of 26 participants classified in three groups: sitting, leaning and standing postures, rode on the same bus along a 45-min route. Ride comfort was worst-off for standing passengers and least uncomfortable for sitting passengers. A strong statistical correlation was found between participants’ subjective ratings with lateral acceleration and duration of turning movement. A second bus run was followed with a sample of 11 participants to collect additional passengers’ ratings. Lateral ride discomfort thresholds were thus established for bus negotiating roundabouts, intersections and along links. The three levels of ride discomfort are Uncomfortable, Very Uncomfortable and Extremely Uncomfortable with average lateral accelerations of ay = 1.5, 1.75 and 2.0 m/s2, respectively. The lateral ride discomfort thresholds would be useful for several value-add applications which include better vehicle design including its interiors, and better vehicle handling about the road layout. With the advent of autonomous public transport (APT), the ride discomfort thresholds must also be considered as valuable input for APT vehicle operation.Accepted versio

Bus Ride Index – a refined approach to evaluating road surface irregularities

The road surface quality can be assessed with ride comfort indices because of their strong correlation. Many studies on ride comfort have focused on cars and trucks, but their results are not applicable to buses, which are characterised by inherently different vehicle dynamics. In this study, a quarter-vehicle simulation concept was used to develop a Bus Ride Index (BRI) for evaluating the effect of road irregularities on bus ride comfort. A BRI model was developed to optimise ride comfort depending on seat configuration and air suspension and validated according to technical data. The results show a good regression relationship between BRI and the International Roughness Index (IRI). New IRI thresholds with regard to ride comfort and bus operating speeds were established to serve as a benchmark to develop better pavement maintenance strategies for bus lanes and to estimate road quality based on acceleration data.National Research Foundation (NRF)Accepted versionThis work is a part of PhD study of the first author and financially supported by the National Research Foundation Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) programme

How do social cues from other passengers affect word-of-mouth and intention to continue using bus services? A second-order SEM approach

Word-of-mouth (WOM) and intention to continue use (ICU) are the two critical components of customer loyalty towards a particular service. There has been a large body of research investigating the effect of determinants on the loyalty formation of public transport passengers. However, the impact of social cues from other passengers, which are part of the social environment, have received less attention. This study developed a theoretical model to examine the complex relationships among the cues from other passengers, perceived security and safety, perceived value, WOM and ICU. Cues from other passengers involved three dimensions: similarity, physical appearance, and suitable behaviour. These three dimensions were measured using a formative approach in structural equation modelling (SEM). Additionally, the moderating effects of demographic characteristics on the formation of public transport passenger behaviours were explored by multi-group SEM. The model was empirically tested using data collected from more than 870 bus passengers in two big cities in Vietnam (Ho Chi Minh and Danang city). The results showed that social cues from other passengers have a strong predictive power over the WOM and ICU of bus passengers. The study successfully demonstrated the critical role of demographic characteristics as moderators on loyalty formation. The findings reported in the present investigation provide several theoretical and practical implications.</p

Mobile phone use among car drivers and motorcycle riders: The effect of problematic mobile phone use, attitudes, beliefs and perceived risk

Mobile phone use while driving presents significant risks, potentially leading to injury or death through distracted driving. Using a case study of Vietnam, this research aimed to understand the effect of problematic mobile phone use (also known as mobile phone addiction or compulsive mobile phone use), attitudes and beliefs, and perceived risk on the frequency of mobile phone use among motorcyclists and car drivers. A self-administered questionnaire was distributed to motorcyclists (n1= 529) and car drivers (n2= 328) using an online survey and face-to-face survey. The survey took around 20-min to complete and participants were entered into a lottery for supermarket vouchers. Of the motorcyclists, 42% of the sample (the highest proportion) was in the 18-25 age group while the 36-45 age group accounted for the highest proportion among car drivers (34.8%). Using structural equation modelling (SEM), key findings showed that each construct influenced mobile phone use, but in different ways for motorcycle riders and car drivers. Attitudes and beliefs had the largest effect on mobile phone use while riding among motorcyclists, with problematic mobile phone use having the smallest influence. In contrast, problematic mobile phone use had the largest effect on mobile phone use while driving a car, with attitudes and beliefs having the smallest effect. The findings of this study point to the need for tailored interventions involving a range of actors (policymakers, police enforcement, mental health professionals, advocacy groups and the wider community) to raise awareness, modify attitudes and increase risk perception associated with mobile phone use while driving/riding. This can be achieved thorough educational tools and road safety campaigns which are focused on reducing this risky driving behaviour. This includes customising road safety programs for individuals and groups affected by problematic mobile phone use such as targeted advertising.</p

Platooning of autonomous public transport vehicles : the influence of ride comfort on travel delay

The development of advanced technologies has led to the emergence of autonomous vehicles. Herein, autonomous public transport (APT) systems equipped with prioritization measures are being designed to operate at ever faster speeds compared to conventional buses. Innovative APT systems are configured to accommodate prevailing passenger demand for peak as well as non-peak periods, by electronic coupling and decoupling of platooned units along travel corridors, such as the dynamic autonomous road transit (DART) system being researched in Singapore. However, there is always the trade-off between high vehicle speed versus passenger ride comfort, especially lateral ride comfort. This study analyses a new APT system within the urban context and evaluates its performance using microscopic traffic simulation. The platooning protocol of autonomous vehicles was first developed for simulating the coupling/decoupling process. Platooning performance was then simulated on VISSIM platform for various scenarios to compare the performance of DART platooning under several ride comfort levels: three bus comfort and two railway criteria. The study revealed that it is feasible to operate the DART system following the bus standing comfort criterion (ay = 1.5 m/s2) without any significant impact on system travel time. For the DART system operating to maintain a ride comfort of the high-speed train (HST) and light rail transit (LRT), the delay can constitute up to 10% and 5% of travel time, respectively. This investigation is crucial for the system delay management towards precisely designed service frequency and improved passenger ride comfort.NRF (Natl Research Foundation, S’pore)Published versio