Engineering Commons^™

Assessment Of Engineering Performance And Environmental Impacts Of High Reclaimed Asphalt Pavement (Rap) Asphalt Mixtures In Flexible Pavements, Ibrahim A.I.E. Elnaml

LSU Doctoral Dissertations

Due to the critical role of asphalt pavements in national infrastructure development, there is a pressing need to investigate more sustainable materials and approaches. The use of natural aggregates and asphalt binders in asphalt pavement presents sustainability challenges due to the depletion of finite resources. Recycling Asphalt Pavement (RAP) offers a promising sustainable solution by substituting virgin aggregates and asphalt binders with recycled ones. However, increasing RAP contents in asphalt mixtures (>25%) can lead to premature cracking, insufficient durability, and limited longevity due to the presence of aged RAP-asphalt binder. To address these concerns, the application of novel recycling …

Understanding And Modeling Drivers’ En-Route Diversion Behavior During Congestion, Mohammad Shapouri

LSU Doctoral Dissertations

In the field of transportation, traffic assignment models primarily have been used to forecast driver route preferences, translating their choices into traffic flow patterns across networks. These models are grounded in distinct behavioral theories and strive to explain how drivers navigate routes based on network features and personal tendencies. Using an aggregation approach, conventional traffic assignment models distribute demand among paths, considering utility and attractiveness. Despite their prevalent use in transportation planning and operations, the fundamental behavioral assumptions of these models have rarely been thoroughly explored. This gap is further compounded by their limited consideration of real-time adjustments and choices …

Understanding And Modeling Drivers’ En-Route Diversion Behavior During Congestion, Mohammad Shapouri

LSU Doctoral Dissertations

In the field of transportation, traffic assignment models primarily have been used to forecast driver route preferences, translating their choices into traffic flow patterns across networks. These models are grounded in distinct behavioral theories and strive to explain how drivers navigate routes based on network features and personal tendencies. Using an aggregation approach, conventional traffic assignment models distribute demand among paths, considering utility and attractiveness. Despite their prevalent use in transportation planning and operations, the fundamental behavioral assumptions of these models have rarely been thoroughly explored. This gap is further compounded by their limited consideration of real-time adjustments and choices …

Toward A Safer Transportation System For Senior Road Users, Saba Doulabi

LSU Doctoral Dissertations

Senior pedestrians and drivers (65 years and older) are among the most vulnerable road users. As the population of seniors rise, concerns regarding older adults' traffic safety are growing. The advantages of using autonomous vehicles, innovative vehicle technologies, and active transportation are becoming more widely recognized to improve seniors' mobility and safety. This behooves researchers to further investigate senior road users’ safety challenges and countermeasures. This study contributes to the literature by achieving two main goals. First, to explore contributing factors affecting the safety of older pedestrians and drivers in the current transportation system. Second, to examine seniors’ perceptions, preferences, …

A New Generation Of Open-Graded Friction Course For Enhanced Durability And Functionality, Hossam Abohamer

LSU Doctoral Dissertations

This study aims at (1) enhancing Open Graded Friction Course (OGFC) mixes durability using additives and other by-products; (2) investigating the impacts of selected factors on OGFC pavements seepage characteristics; (3) developing a quantitative tool to model the deterioration in OGFC pavements functional performance; and (4) developing new guidelines of Air Void (AV) content for OGFC for optimum functionality and durability. For the durability objective, eight mixes were prepared with a PG 76-22 binder and two sources of aggregate (i.e., # 78 limestone and # 67 sandstone). Three Warm Mix Additives (WMA), one by-product (i.e., crumb rubber [CR]), and two …

Development Of Cracking Resistance Prediction Model Of Long-Term Aged Asphalt Mixtures, Peyman Barghabany

LSU Doctoral Dissertations

With the increasing complexity of asphalt mixture composition, the current volumetric-based Superpave mixture design would not be sufficient to address durability concerns. To address this limitation, performance-based testing is introduced to supplement conventional volumetric mixture design in assessing the cracking resistance of asphalt mixtures. To perform cracking tests, samples need to be aged to represent the most embrittlement case. The current AASHTO standard for asphalt mixture long-term aging (LTA) is a 5-day oven-aging at 85°C. Quality control/assurance practices require samples to be long-term aged prior to a cracking test which is a time-consuming process. Therefore, it would be beneficial to …

Developing A Competency Model For Highway Safety Engineers: A Delphi Method, Garrett K. Wheat

LSU Doctoral Dissertations

The primary purpose of this study was to determine the core competencies needed by State DOT Highway Safety Engineers as perceived by Highway Safety experts in the United States. First, a list of competencies was identified. Next, a panel of Highway Safety experts determined the importance of each identified competency for the current year (2020) and for the future (year 2030). Finally, ratings provided by the panel were tested for the presence of consensus.

For this study, the researcher used a Delphi Method as classified by Delbecq, Van de Ven, and Gaustafson (1975). Through this method, a panel of forward-thinking …

Using Spatial Analysis And Machine Learning Techniques To Develop A Comprehensive Highway-Rail Grade Crossing Consolidation Model, Samira Soleimani

LSU Doctoral Dissertations

The safety of highway-railroad grade crossings (HRGC) is still an issue in the United States of America (USA). The grade crossing is where a railroad crosses a road at the same level without any over or underpass. To improve the safety of crossings, the crossings’ condition should be explored from several aspects such as engineering design (speed limit, warning signs, etc.), road condition (number of lanes, surface markings, etc.), rail design (the type of track, ballast, etc.), temporal variables (weather, visibility, time of day, lightning, etc.), social variables (population, race, etc.), and last but not least, spatial variables (the type …

Effect Of Light Activated Self-Healing Polymers On The Performance Of Asphalt Pavement Containing Recycled Asphalt Materials (Rap/Ras), Sharareh Shirzad

LSU Doctoral Dissertations

A new generation of Ultraviolet (UV) light-induced self-healing polymers was introduced for the asphalt pavement application with the aim to enhance pavements durability while increasing its service life. The developed self-healing polymer was mixed with asphalt binder using two different methods, passive and reactive. For the passive method, the cured self-healing polymer was ground to smaller particle size and then it was mixed with asphalt binder using a high shear stirrer and at a high temperature. For the reactive method, self-healing polyurethane pre-polymer was added to the asphalt binder at a lower temperature and lower shear rate compare to the …

Field Performance And Cost Effectiveness Of Crack Sealing In Flexible And Composite Pavements, Momen Ragab Mousa

LSU Doctoral Dissertations

Surface cracking is one of the major surface distresses in asphalt concrete (AC) pavement, allowing water infiltration through the cracks, causing stripping in asphalt pavement layers, and weakening and deteriorating the base and/or subgrade. Its treatment, therefore, is one of the major activities in pavement preservation for many state DOTs. Among the various treatment methods currently available to preserve AC pavement with existing surface cracking are various forms of crack sealing. Crack sealing is not a common practice to Louisiana highways since the benefit of such treatment appears to be affected by the elevation of the ground water table. Studies …

Crash/Near-Crash: Impact Of Secondary Tasks And Real-Time Detection Of Distracted Driving, Peter Ramzy Zaki Bakhit

LSU Doctoral Dissertations

The main goal of this dissertation is to investigate the problem of distracted driving from two different perspectives. First, the identification of possible sources of distraction and their associated crash/near-crash risk. That can assist government officials toward more informed decision-making process, allowing for optimized allocation of available resources to reduce roadway crashes and improve traffic safety. Second, actively counteracting the distracted driving phenomenon by quantitative evaluation of eye glance patterns.

This dissertation research consists of two different parts. The first part provides an in-depth analysis for the increased crash/near-crash risk associated with different secondary task activities using the largest real-world …

Machine Learning Tools For Optimization Of Fuel Consumption At Signalized Intersections In Connected/Automated Vehicles Environment, Saleh Ragab Mousa

LSU Doctoral Dissertations

Researchers continue to seek numerous techniques for making the transportation sector more sustainable in terms of fuel consumption and greenhouse gas emissions. Among the most effective techniques is Eco-driving at signalized intersections. Eco-driving is a complex control problem where drivers approaching the intersections are guided, over a period of time, to optimize fuel consumption. Eco-driving control systems reduce fuel consumption by optimizing vehicle trajectories near signalized intersections based on information of the SpaT (Signal Phase and Timing). Developing Eco-driving applications for semi-actuated signals, unlike pre-timed, is more challenging due to variations in cycle length resulting from fluctuations in traffic demand. …

Development Of Self-Healing Mechanisms For Asphalt Pavements, Max Abelardo Aguirre Deras

LSU Doctoral Dissertations

Self-healing mechanisms, such as microcapsules or hollow-fibers, filled with an asphalt rejuvenator present an emerging technology that would enhance an asphalt mixture’s resistance to cracking damage caused by vehicular and environmental loading. The objectives of this study were to: (a) Evaluate the effects of asphalt rejuvenators on hot-mix asphalt mixtures in order to test its effects on the fundamental engineering properties of the mixtures at high and intermediate temperatures; (b) Develop a synthesis procedure for production of microcapsules and hollow-fibers containing an asphalt rejuvenator; (c) Evaluate the self-healing efficiency of double-walled microcapsules and hollow-fibers filled with an asphalt rejuvenator, through …

Automated Merging Control Algorithm: A Cooperative Approach For Connected Automated Vehicles In Platoons, Sogand Karbalaieali

LSU Doctoral Dissertations

Transportation systems are being transformed by advanced vehicular connectivity and automation. Human-driven vehicles are being replaced by Connected Automated Vehicles (CAV). The US Department of Transportation’s (DOT) Intelligent Transportation System Joint Program Office (ITS JPO) promotes automated vehicle research which encourages the development and deployment of automated vehicles by infrastructure-based solutions. Advancements in traffic design and operation can offer solutions to the challenges that CAVs face. An example of these challenges is merging on highways where traffic operation could be enhanced by the use of Vehicle to Infrastructure (V2I) communication between the onramp and the mainline vehicles and roadside units …

Sustained Flow Index: A Stochastic Measure Of Freeway Performance, Siavash Shojaat

LSU Doctoral Dissertations

The capacity of a road addresses its quantitative traffic carrying ability. The estimation of capacity as a parameter to assess traffic flow performance on freeway facilities has received considerable attention in the literature. Research into the traffic operation at high volumes reveals that the capacity of freeways is not a fixed number, but rather a random variable. Thus, in a stochastic approach to freeway capacity of estimation, the capacity is treated as a random variable generated from a population of flow observations, stemmed from a certain distribution function. Since the type of capacity distribution function is generally not known with …

Development Of A Mode And Destination Type Joint Choice Model For Hurricane Evacuation, Ruijie Bian

LSU Doctoral Dissertations

Since Hurricane Katrina, transit evacuation service has been seen to serve critical needs in affected cities and an increasing number of hurricanes have struck the east coast where more people rely on public transportation to evacuate. Thus, it is important to model mode choice in evacuation for a better estimation of evacuation transit demand. In this study, a joint mode and destination type choice model was estimated based on multiple post-storm behavioral surveys from the northeastern seaboard to the Gulf coast. A Nested Logit model specification was used to estimate this joint choice model. The estimated model showed significant linkage …

An Enhanced Bridge Weigh-In-Motion Methodology And A Bayesian Framework For Predicting Extreme Traffic Load Effects Of Bridges, Yang Yu

LSU Doctoral Dissertations

In the past few decades, the rapid growth of traffic volume and weight, and the aging of transportation infrastructures have raised serious concerns over transportation safety. Under these circumstances, vehicle overweight enforcement and bridge condition assessment through structural health monitoring (SHM) have become critical to the protection of the safety of the public and transportation infrastructures. The main objectives of this dissertation are to: (1) develop an enhanced bridge weigh-in-motion (BWIM) methodology that can be integrated into the SHM system for overweight enforcement and monitoring traffic loading; (2) present a Bayesian framework to predict the extreme traffic load effects (LEs) …