Isolated approaches at signalized intersections with posted speed limits of 45 mph or greater generally experience large numbers of rear-end and angle collisions. A combination of less attentive drivers, high operating speeds, and less than ideal intersection characteristics can result in crash frequencies well above expected rates. A number of...
The first edition of the Highway Safety Manual (HSM) provides a quantitative
approach to predict the safety of transportation facilities based on the recently
developed scientific methods. This approach, known as the predictive method, was
developed for several states in the United States. Due to differences in driver
population, weather...
In response to the growing environmental concern and higher operating cost of regular automobile, the concept of Low-Speed Vehicles (LSVs) is becoming popular as a sustainable mode of transportation. Primarily designed for protected environments and gated communities, the use of these vehicles is gradually increasing on public roadways as a...
The author of the Highway Safety Manual (HSM) Part B developed a predictive method for safety management. A software tool for highway safety system analysis called the SafetyAnalyst is developed basing on HSM Part B. The author describes an effort to evaluate the feasibility of SafetyAnalyst in Oregon. Seven sample...
Posting advisory speed signs at sharp horizontal curve sites is a practice well established in the United States. The purpose of these signs is to provide the driving public with a safe speed to negotiate such curves; however, the link between these signs and safety has not yet been clearly...
Three-dimensional laser scanning has revolutionized spatial data acquisition and can be completed from a variety of platforms including airborne (ALS), mobile (MLS), and static terrestrial (TLS) laser scanning. MLS is a rapidly evolving technology that provides increases in efficiency and safety over static TLS, while still providing similar levels of...
Driving simulation is widely accepted as a safe, effective, and economical alternative for investigating driver behavior in a variety of contexts. However, in order to apply simulator-based research results to real-world settings, the performance measures acquired through simulated driving experiments must first be validated. This research was aimed at validating...
Roundabouts have become an alternative for traditional intersections due to the safer operational performance. Previous research has provided crash modification factors (CMFs) as a criterion based on before-after studies as to evaluate the safety performance of roundabouts. One drawback of assessment based on crash modification factors, however, is that a...
Background
The National Science Foundation (NSF) has funded multiple research projects dedicated to the development of research and evidence based instructional strategies in an effort to improve the state of science, technology, engineering and math (STEM) education in the US. These efforts have led to an abundance of research based...
It is expected that information taught in the context of school will ultimately transfer to workplace settings. To support this transition, educators and researchers advocate for organizing foundational ideas, or concepts, in specific domains of knowing. In the domain of transportation engineering, knowing of concepts, which include "big ideas" such...
Highway capacity has traditionally been treated as deterministic. In reality, however, capacity can vary from time to time and location to location due to inclement weather, various driving behavior, traffic incident, bottleneck and workzone. This thesis aims to characterize the stochastic variations of highway capacity, and explore its applications.
The...
Degradation of watersheds is a major concern in areas where adverse climate effects and unsustainable use of the natural resources have caused extensive stresses to watershed systems (e.g., increased floods, increased droughts, worsened in-stream water quality) through the years. While considerable efforts are being made to generate technical solutions that...
Improving safety education could contribute to the preparation of better professional engineers. Safety topics are not holistically embedded in transportation course curricula. This thesis explores the current state in which safety is being incorporated in transportation course curricula in terms of design and compares the uses of safety data in...
Student engagement in a course plays a vital role in a student’s ability to process and construct knowledge. Student engagement research has investigated how students engage in and out of the classroom on a macro scale, through observation and survey data collection of large student populations, which lack focus on...
Increasingly congested surface transportation network in urban areas and grow-ing land values make underground transportation systems more attractive for high-ways (i.e., tunnels) and metro system compared to other options [1]. An underground transportation system can preserve the land above for recreational parks, commer-cial buildings, residential homes, or other purposes while...
While riding bicycles has been promoted for its health, economic, and environmental benefits, it also complements other modes to complete a safe, efficient, and reliable transportation system. However, the dramatic increase of bicycle usage in the U.S. is accompanied by a growth of bicycle crashes. The U.S. Department of Transportation,...
The advancement of the cutting-edge technologies of advanced driver assistance systems (ADAS) hold promises to reshape the future of the transportation system. The concept of connected (CV) and connected automated vehicles (CAV) technologies are live examples of the future transportation. Vehicle communication technology is expected to impact conventional traffic conditions....
The two primary considerations for highway work-zones are its effect on commuter mobility and worker safety which are often spoken of together. However, it must be noted that they often conflict with each other. For example, traffic control plans that reduce travel speed in work-zones improve both commuter and worker...
Bridges are a vital component of transportation infrastructure in the United States, and the continual maintenance and preservation of bridges is critical to maintaining their structural capacity and maximizing service life. One of the most significant issues faced by concrete bridges is the infiltration of moisture from the roadway surface...
Passenger security screening is a continuously evolving process and not much is known about how passengers perceive its effectiveness in keeping air travel safe. The provided thesis consists of two manuscripts that expand the literature on passenger perception of safety through the application of advanced econometric techniques. This thesis aims...
The rapid growth in the number of roundabouts raises some significant research challenges, especially around safety performance and evaluation in the U.S. Despite the safety advantages that roundabout geometric design brings, crashes still occur. While operationally roundabouts are good at preventing severe crashes, they may lead to more less severe...
Social scientists have studied people's responses to disasters for many decades, and behavioral commonalities and variations are summarized in different mental schemes/models in disaster studies. Integrating those findings from social science into evacuation simulation can improve simulation accuracy and eventually better support decision-making and disaster preparedness. However, this kind of...
The resistance of asphalt concrete pavement to distresses such as fatigue cracking and permanent deformation is governed by how well the structure can resist loading under a variety of traffic and climate-related conditions. Asphalt binder type and content are typically the variables that pavement engineers can manipulate to render the...
The outbreak of the Coronavirus Disease 2019 (COVID-19) and the restrictions implemented in response to it (e.g., stay-at-home orders, social distancing mandates, business closures) had unprecedented effects on the trucking industry. The pandemic prompted the first significant overhaul of federal hours-of-service (HOS) regulations in over 15 years. Prior to the...
Considering the deadly impacts of commercial motor vehicle (CMV) crashes on road safety, many previous studies have put in efforts to find the determinants of CMV crash injury severities. However, studies examining the impact of the different number of lanes on CMV crash
injury severities are lacking. Besides, the importance...
The onset of the COVID-19 pandemic led to significant transformations in global mobility patterns, primarily driven by stay-at-home orders and economic shutdowns. These measures resulted in a substantial decline in travel activities worldwide. In the United States, there was a notable reduction in travel demand, with a corresponding decrease in...