Investigating the impacts of autonomous vehicles on crash severity and traffic safety

Traffic accidents are a nationwide public health concern, but autonomous vehicles (AVs) have the potential to significantly reduce accident severity and frequency by eliminating their most common cause, human error. By analyzing the data published by California’s Department of Motor Vehicles, researchers have identified the factors that influence AV crash severity, however, none do so through a literature review. This paper’s aims are multi-faceted: to understand AVs’ operation on public roadways by identifying and classifying the factors contributing to accident severity, to develop a list of strategies that address the public’s safety concerns, and to acknowledge the ethics of unavoidable collisions. To fulfill these objectives, a comprehensive literature review was conducted based on a keyword search. Following a multi-step screening and exclusion process, detailed review was performed of 107 relevant publications, and the factors contributing to increased crash severity were classified into 14 categories. The literature revealed that AVs are not at fault in most accidents, although they have a higher propensity than conventional cars to be involved in rear-end collisions, and they are specifically designed to minimize the number of accidents, but may face unavoidable ones. For the benefit of policymakers and manufacturers, 11 strategies that address the moral dilemma of these accidents and 7 strategies that address concerns about AV safety to improve public perception were identified

Factors that determine a university community’s satisfaction levels with public transit services

Introduction: Universities and other educational institutions across the United States collaborate with service providers to afford their students, faculty, and staff transit services, such as dedicated buses, on-demand ridesharing, and public transportation. The university community relies on these services, especially in rural and low-density areas without fixed-route transit services. The literature on this topic has a wealth of detailed material about the travel and usage patterns of public transit systems, but it has little information about users’ satisfaction with the transit services provided by universities.Method: This study focuses on filling this gap by using descriptive statistics and ordered logistic regression to determine how satisfied users are with university transit services and what factors are associated with their level of satisfaction. Four public transit services available to the University of Texas at Arlington community served as our case studies.Results and Discussion: The results revealed that most users are satisfied with the services overall. Riders were highly satisfied with service attributes like ease of boarding, cleanliness, customer service, and vehicle speed of the four services. On the other hand, they were least satisfied with service availability and wait times of these services. The findings from this study may be used to provide the UTA community with better mobility and accessibility options and to evaluate the levels of satisfaction with similar services offered to other university communities

Resilience in Water Infrastructures: A Review of Challenges and Adoption Strategies

An increase in the number and strength of natural catastrophes experienced over the past few decades has accelerated the damage sustained by infrastructures. Drinking water and wastewater infrastructure systems are critical aspects of a healthy environment, and their ability to withstand disasters is vital for effective disaster response and recovery. Although numerous studies have been conducted to determine the challenges that natural disasters render to water infrastructures, few extensive examinations of these challenges have been conducted. The goal of this study, therefore, was to identify and categorize the challenges related to the resilience of drinking water and wastewater infrastructures, and to determine the strategies that most effectively minimize their unintended consequences. A comprehensive evaluation of the existing literature was conducted, and 537 publications were collected. After extensive screening, 222 publications were selected for rigorous evaluation and analysis based on the data collection methods and other criteria. A total of fifty-one (51) challenges were determined and classified, within the following five categories: environmental, technical and infrastructure, social, organizational, and financial and economic. The challenges were then ranked within each category according to their frequency of occurrence in previous research. The results reveal that climate change, aging infrastructure, lack of infrastructure capital, population growth, improper maintenance of water infrastructure, and rapid urbanization are the most frequently cited challenges. Next, 30 strategies and approaches were identified and categorized into either preventive or corrective actions, according to their implementation time. The findings of this study will help decision- and policymakers properly allocate their limited funding to enhance the robustness of their water infrastructures before, during, and after natural hazards

Study of Design and Construction of Transit Facilities in Rural Areas in USA

The United States rural transit facilities have a considerable impact on annual transportation expenditures as there are many of them and they are geographically dispersed. It is challenging to estimate the design and construction costs of the facilities, as the historical and documented cost database is insufficient; therefore, the ultimate aim of this study was to establish a baseline estimate for design and construction costs. Additionally, the key information associated with the different aspects of rural transit facility projects was also provided in this study. Interviews were conducted with professional managers of different departments of transportation (DOTs) who were involved in rural transit projects. A structured survey was then developed and distributed to various DOT representatives, and 26 of them were completed and returned. Two regression models were generated by utilizing the survey data to predict the design and construction costs of rural transit facilities, based on the size of the projects. Furthermore, the results revealed that issues arising from soil conditions and unexpected underground conditions are frequently risk factors for construction of transit facilities. It was also concluded that the popular approach to estimating the cost of the design and construction phases associated with transit facility projects is to use the data from similar projects. These findings support the need for additional literature to provide a baseline estimate for design and construction costs and key information of different important aspects of rural transit facilities

Resilience in Water Infrastructures: A Review of Challenges and Adoption Strategies

An increase in the number and strength of natural catastrophes experienced over the past few decades has accelerated the damage sustained by infrastructures. Drinking water and wastewater infrastructure systems are critical aspects of a healthy environment, and their ability to withstand disasters is vital for effective disaster response and recovery. Although numerous studies have been conducted to determine the challenges that natural disasters render to water infrastructures, few extensive examinations of these challenges have been conducted. The goal of this study, therefore, was to identify and categorize the challenges related to the resilience of drinking water and wastewater infrastructures, and to determine the strategies that most effectively minimize their unintended consequences. A comprehensive evaluation of the existing literature was conducted, and 537 publications were collected. After extensive screening, 222 publications were selected for rigorous evaluation and analysis based on the data collection methods and other criteria. A total of fifty-one (51) challenges were determined and classified, within the following five categories: environmental, technical and infrastructure, social, organizational, and financial and economic. The challenges were then ranked within each category according to their frequency of occurrence in previous research. The results reveal that climate change, aging infrastructure, lack of infrastructure capital, population growth, improper maintenance of water infrastructure, and rapid urbanization are the most frequently cited challenges. Next, 30 strategies and approaches were identified and categorized into either preventive or corrective actions, according to their implementation time. The findings of this study will help decision- and policymakers properly allocate their limited funding to enhance the robustness of their water infrastructures before, during, and after natural hazards

Analyzing the factors affecting construction project schedules amidst COVID-19 pandemic

The global health crisis caused by the COVID-19 pandemic led to disruptions and challenges across many business sectors, including the construction industry. A serious ramification of the pandemic on the construction industry was an increase in the number of project schedule delays that affected a multitude of projects around the world. Although the current literature explores the factors that cause project schedule delays, little research is available on the impact of variables, such as the size of the industry, type of project, and category of the organization, on the delays. This study used a four-step approach to address this knowledge gap by performing a comprehensive literature search, developing a survey, distributing the survey online, and conducting a quantitative analysis of the responses. The study's findings revealed that the factors contributing to project schedule overruns during the pandemic were diverse and differed with the variables cited above. Distinct differences were observed in areas such as procurement of materials and changes in material specifications and prices. This research sheds light on the multifaceted nature of the variables that impacted construction project schedules during the COVID-19 pandemic and provides valuable insights for industry stakeholders as they seek to establish effective strategies that will minimize risks and enhance project delivery during future periods of crisis

A Review on Construction Safety: Hazards, Mitigation Strategies, and Impacted Sectors

Hazard identification is a fundamental step in safety management that has the potential to reduce the number and severity of occupational injuries on construction sites. Researchers have identified and evaluated some of the hazards, but few have extensively discussed all of them and none have classified them by sector. The goal of this paper is to fill that research gap by considering hazard identification through an organized synthesis of the existing literature. After a comprehensive literature review, 236 publications were deemed eligible for further analysis. Eighteen safety hazards were identified and then categorized into four groups based on their physiological impacts, ranked based on frequency of citation, and classified by sector. The results revealed that falls from heights, material handling, and heavy machinery were the most frequently cited hazards and the most likely to impact all sectors. Mitigation strategies were also identified, and it was determined that most hazards can be mitigated through the use of personal protective equipment, and effective training and supervision

Cross-functional collaboration in the early phases of capital projects: Barriers and contributing factors

In early project phases, cross-functional collaboration is required to lead a capital project from an investment option to a full definition before its design and construction commenced. Given that many capital projects are large, complex, and take years to develop, for stakeholders to realize effective project definition and development it is important that they identify—in the early phases—cross-functional collaboration barriers and their contributing factors. The current study conducted a total of 20 interviews with experts from both the business units and project teams in owner companies and Engineering, Procurement, and Construction (EPC) contractors. It identified 14 barriers to effective cross-functional collaboration and 43 associated contributing factors in the early phases of capital projects. To rank the barriers, researchers then applied the Delphi method with a panel of 12 subject matter experts (SMEs). The outcomes of this study can guide practitioners to improve the effectiveness of cross-functional collaboration in early project phases

Identifying individuals’ perceptions, attitudes, preferences, and concerns of shared autonomous vehicles: During- and post-implementation evidence

Shared autonomous vehicles (SAVs) have the potential to improve the efficiency, mobility, safety, and affordability of transportation systems; however, consumers will determine whether they can be successfully integrated into the current systems. This study aims to identify the perceptions, attitudes, preferences, and concerns of those who have and have not taken advantage of the AV technology by sharing the results of a self-driving technology demonstration in Arlington, Texas. A two-step approach was employed for this study: (a) quantitative analysis of a self-reported survey of SAV users and non-users who experienced SAVs on the road, and (b) a qualitative study of interviews conducted during the post-implementation phase of the project. The results from an ordinal logistic regression of a self-reported survey showed that the ease of using SAVs because of not having to worry about parking is positively associated with individuals' willingness to use them in the future. In contrast, concerns about possible confusion arising between human drivers and SAVs on the street decrease willingness to use SAVs. A qualitative analysis of interviews conducted on this subject indicated that waiting time, pick-up and drop-off locations, and the ability to make tight turns in intersections are the three major concerns. Potential riders anticipate that SAVs will be more cost-efficient, safer, and environmentally friendly than owner-operated vehicles. This study provides insights into the perceptions and attitudes of SAV users and non-users and identifies strategies for successfully integrating an SAV service with an existing on-demand ridesharing service, thereby enhancing future acceptance of the technology