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Title: Developing Warrants for Designing Continuous Flow Intersection and Diverging Diamond Interchange.
Creator: Almoshaogeh, Meshal, Radwan, Essam, Abdel-Aty, Mohamed, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: The main goal of this dissertation is to have better understanding of design and operation of the Continuous Flow Intersection (CFI) and Diverging Diamond Interchange (DDI) - as well as numerous factors that affect signalized intersection and interchange performance due to increased left-turn demand. The dissertation attempts to assess the need and justification to redesign intersections and interchanges to improve their efficiency. And to that end, an extensive literature review of existing...
Show moreThe main goal of this dissertation is to have better understanding of design and operation of the Continuous Flow Intersection (CFI) and Diverging Diamond Interchange (DDI) - as well as numerous factors that affect signalized intersection and interchange performance due to increased left-turn demand. The dissertation attempts to assess the need and justification to redesign intersections and interchanges to improve their efficiency. And to that end, an extensive literature review of existing studies was done with the prime aim of perceiving the principles of these innovative designs and determining the methodology to-be-followed, in order to reach the study's core. Accordingly, several DDI and CFI locations were selected as candidate locations, where the designs have already been implemented and the required data - to model calibration and validation - was collected. The micro-simulation software (VISSIM 8.0) was used for simulation, calibration and validation of the existing conditions - through several steps - including signal optimization and driving behavior parameter sensitivity analysis. Subsequently, an experiment was conceived for each design, aiming at examining several factors that affect each design's efficiency. The experiment comprised 180 and 90 different CFI (&) DDI scenarios and their conventional designs, respectively. Two measures of effectiveness were identified for result analysis: the average delay and capacity. Result analyses were performed to detect switching thresholds (from conventional to innovative designs. In addition, performance comparison studies of the CFI and DDI with their conventional designs were performed. The results and findings will serve as guidelines for decision-makers as to when they should consider switching from conventional to innovative design. Finally, decision support systems were developed to speed up the search for the superior design, in comparison with others.
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Date Issued: 2017
Identifier: CFE0007276, ucf:52187
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007276

Title: Impact of the longer change and clearance intervals on signalized intersections and corridors.
Creator: Alfawzan, Mohammed, Radwan, Essam, Eluru, Naveen, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: Evaluating the impact of longer change and clearance intervals on signalized intersections and corridors is the main goal of this study. In fact, the Florida department of Transportation (FDOT) has adopted a new signal retiming effort in a number of signalized intersections along several corridors. The Orange County started implementing the new signal timing from December, 2013 and completed it in June, 2015. The other objective of this new signal timing is to minimize the red light running...
Show moreEvaluating the impact of longer change and clearance intervals on signalized intersections and corridors is the main goal of this study. In fact, the Florida department of Transportation (FDOT) has adopted a new signal retiming effort in a number of signalized intersections along several corridors. The Orange County started implementing the new signal timing from December, 2013 and completed it in June, 2015. The other objective of this new signal timing is to minimize the red light running rate. This study is dedicated to investigate the signal retiming effort adopted by the FDOT and how the new signal timing might impact the studied signalized intersections' performance and safety. To address this issue, a number of signalized intersections along three corridors in Orange County were investigated during different three time of the day periods AM, MD, and PM. Additionally, three categories of signal timings were adopted to better understand the performance and safety of old (pattern 1), current (pattern 2), and proposed (pattern 3) signal timings. The analysis was based on the Simtraffic simulation which is a part of Synchro 8 software. The research results provide that the signalized intersection's performance along the three corridors during the three plans of the day were found significantly affected by lengthening the change and clearance intervals. Signal timing 2 and 3 were observed significantly different than signal timing 1 which have greater intersection delay, queue length, intersection overall volume to capacity v/c ratio, and Intersection capacity utilization ICU. Furthermore, the results show that the signal timing 2 and signal timing 3 significantly increase the total delay and travel time along the studied arterials during the three plans of the day.
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Date Issued: 2016
Identifier: CFE0006064, ucf:50970
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006064

Title: Analysis of pedestrian safety using micro-simulation and driving simulator.
Creator: Wu, Jiawei, Radwan, Essam, Abdel-Aty, Mohamed, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: In recent years, traffic agencies have begun to place emphasis on the importance of pedestrian safety. In the United States, nearly 70,000 pedestrians were reported injured in 2015. Although the number only account for 3% of all the people injured in traffic crashes, the number of pedestrian fatalities is still around 15% of total traffic fatalities. Furthermore, the state of Florida has consistently ranked as one of the worst states in terms of pedestrian crashes, injuries and fatalities....
Show moreIn recent years, traffic agencies have begun to place emphasis on the importance of pedestrian safety. In the United States, nearly 70,000 pedestrians were reported injured in 2015. Although the number only account for 3% of all the people injured in traffic crashes, the number of pedestrian fatalities is still around 15% of total traffic fatalities. Furthermore, the state of Florida has consistently ranked as one of the worst states in terms of pedestrian crashes, injuries and fatalities. Therefore, it is befitting to focus on the pedestrian safety. This dissertation mainly focused on pedestrian safety at both midblock crossings and intersections by using micro-simulation and driving simulator. First, this study examined if the micro-simulation models (VISSIM and SSAM) could estimate pedestrian-vehicle conflicts at signalized intersections. A total of 42 video-hours were recorded at seven signalized intersections for field data collection. The observed conflicts from the field were used to calibrate VISSIM and replicate the conflicts. The calibrated and validated VISSIM model generated the pedestrian-vehicle conflicts from SSAM software using the vehicle trajectory data in VISSIM. The mean absolute percent error (MAPE) was used to determine the optimum TTC and PET thresholds for pedestrian-vehicle conflicts and linear regression analysis was used to study the correlation between the observed and simulated conflicts at the established thresholds. The results indicated the highest correlation between the simulated and observed conflicts when the TTC parameter was set at 2.7 and the PET was set at 8. Second, the driving simulator experiment was designed to assess pedestrian safety under different potential risk factors at both midblock crossings and intersections. Four potential risk factors were selected and 67 subjects participated in this experiment. In order to analyze pedestrian safety, the surrogate safety measures were examined to evaluate these pedestrian-vehicle conflicts. Third, by using the driving simulator data from the midblock crossing scenario, typical examples of drivers' deceleration rate and the distance to crosswalk were summarized, which exhibited a clear drivers' avoidance pattern during the vehicle pedestrian conflicts. This pattern was summarized into four stages, including the brake response stage, the deceleration adjustment stage, the maximum deceleration stage, and the brake release stage. In addition, the pedestrian-vehicle conflict prediction model was built to predict the minimum distance between vehicle and pedestrian.Finally, this study summarized the three different kinds of data that were to evaluate the pedestrian safety, including field data, simulation data, and driving simulator data. The process of combining of field data, simulation data, and simulator data was proposed. The process would show how the researches could evaluate the pedestrian safety by using the field observations, micro-simulation, and driving simulator.
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Date Issued: 2017
Identifier: CFE0006822, ucf:51770
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006822

Title: Determining the Feasibility of using Micro Simulation to asses safety of Pedestrian Crossings.
Creator: Darius, Jenner, Radwan, Essam, Abou-Senna, Hatem, Abdel-Aty, Mohamed, University of Central Florida
Abstract / Description: For the past several decades, pedestrian safety has been an oncoming issue that has thrown the area of transportation engineering into a frenzy. Pedestrian safety has become predominantly one of the leading causes of fatalities in traffic accidents. Florida has been reported as one of the leading states in pedestrian fatalities with 2.56 fatality rate per 100,000 population and about 20 percent of all traffic fatalities in the state of Florida. Nonetheless, as research is being done and...
Show moreFor the past several decades, pedestrian safety has been an oncoming issue that has thrown the area of transportation engineering into a frenzy. Pedestrian safety has become predominantly one of the leading causes of fatalities in traffic accidents. Florida has been reported as one of the leading states in pedestrian fatalities with 2.56 fatality rate per 100,000 population and about 20 percent of all traffic fatalities in the state of Florida. Nonetheless, as research is being done and hypotheses are being calibrated and produced, there has to be a way of measuring and determining the number of pedestrian-to-vehicle conflicts without having to yet apply the system on the field without further validation. Moreover, pedestrian-to-vehicle conflicts have been a rising issue in correlation to the pedestrian fatalities. The fact that the highway safety manual has limited information about crash modification functions for pedestrian and that pedestrian fatality is a rare event, it is worthwhile identifying and adopting surrogate safety measures for pedestrian. Thus, having the capability to analyze various surrogate safety measures within the confines of micro simulation would be a great contribution to real-world application. As a result, the purpose of this thesis is to determine the feasibility of using micro simulation to assess safety of pedestrian crossings using specifically VISSIM and SSAM. During this study, a great deal of data extraction was taken from videotapes collected at nine various intersections, each with its own environmental and geometrical factors. Various parameters were taken from the different sites in order to calibrate and validate VISSIM and SSAM. The parameters included traffic and pedestrian volumes, walking speeds, crossing times, signal timings, and pedestrian-to-vehicle conflicts. During this study, an extensive amount of analysis testing was done in order to obtain the optimum threshold within various combinations of thresholds that would define the pedestrian-to-vehicle conflicts. The analysis was initiated for the time to collision (TTC) and post encroachment time (P.E.T) thresholds. This is done so that the typical scenario of an intersection can be analyzed and comparisons can be made efficiently between observed and simulated conflicts. There were 55 combinations of TTC and PET thresholds produced that were also statistically calculated using the mean absolute percent error (MAPE) in order to determine the most efficient threshold for all 9 intersections. Calibration also was done for parameters in VISSIM that included the safety distance factor (SDF) and the Add-stop distance to assess the sensitivity of these parameters in computing the number of pedestrian-to-vehicle conflicts. These thresholds and factors were used for further validation and assessment of the feasibility of the SSAM and VISSIM model. Data results displayed that the simulated conflicts and the observed conflicts illustrated reasonable correlation. However, even with the feasibility of VISSIM and SSAM being validated, there still are questions that arise pertaining to whether VISSIM and other micro simulation can assess real-world driver behavior and the unpredictability of driver maneuvering. More research with more intersections are recommended to be done.
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Date Issued: 2016
Identifier: CFE0006526, ucf:51379
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006526

Title: Analysis of Pedestrian Crash characteristics and Contributing Causes in Central Florida.
Creator: Bianco, Zainb, Abou-Senna, Hatem, Abdel-Aty, Mohamed, Radwan, Essam, University of Central Florida
Abstract / Description: This research investigates the main reasons leading the State of Florida to be ranked among the worst states in terms of pedestrian safety with four metro areas considered the most dangerous for pedestrians among all the United States as reported in the Dangerous by Design report. The study analyzes the characteristics and contributing causes of pedestrian crashes that occurred in Central Florida over a 5 year-period (2011-2015) at intersections and along roadway segments at mid-block...
Show moreThis research investigates the main reasons leading the State of Florida to be ranked among the worst states in terms of pedestrian safety with four metro areas considered the most dangerous for pedestrians among all the United States as reported in the Dangerous by Design report. The study analyzes the characteristics and contributing causes of pedestrian crashes that occurred in Central Florida over a 5 year-period (2011-2015) at intersections and along roadway segments at mid-block locations using the data obtained from the Signal 4 Analytics database. All pedestrian related crashes were compiled and all the 6,789 crash reports were studied thoroughly. Intersection and roadway pedestrian related crashes were identified along with all the parameters and conditions related to the high crash risk of pedestrians. However, due to inconsistencies in the police report inputs such as miscoding and misinterpretation, a screening criteria was developed to exclude or disqualify crashes that do not meet the research requirements. Preliminary descriptive statistics revealed the most common types of crashes at each location. For intersection-related crashes, it was found that left turn, right turn and through moving vehicles struck crossing pedestrians. At mid-block locations, major crash types were through moving vehicles hitting pedestrians crossing and walking along the roadway. The evaluated factors affecting pedestrian crashes were classified into four main categories; location characteristics (e.g. intersection, midblock, type of control, presence of crosswalk, presence of sidewalk), pedestrian factors (e.g. pedestrian under influence, failure to yield to the right of way), driver/vehicle characteristics (e.g. driving under influence, failed to yield to traffic control device, aggressive driving), and environmental-related factors (e.g. weather conditions, road surface conditions and time of day) were among the factors studied.Three different models were utilized in the analysis using the SPSS statistical software package. A multinomial logit model was developed to predict the likelihood that a pedestrian will be involved into one of the common crash types. A binary regression model was developed to understand the significant factors contributing to the main causes at each intersection type whether at signalized or un-signalized intersections. Lastly, an ordinal regression model was developed to identify the significant factors affecting the level of injury severity sustained by pedestrians. The results of the multinomial logit model for intersection crashes revealed a high probability of right turn crashes associated with drivers at fault with no aggressive driving related crashes compared to left turn crashes. The results also showed that the probability of through moving vehicle crashes with no traffic control device was 2.437 times higher than left turn crashes. These results confirmed the results of the binary model that a lower likelihood of left or right turn crashes was associated with un-signalized intersections when compared to through crashes. Lastly, a greater probability of through crashes was associated with running the red light when compared to left turn crashes.The results of the binary model revealed that the majority of the un-signalized intersection crashes were attributed to drivers at fault. Among other contributing factors was crossing at un-signalized intersections not equipped with the crosswalks. The chance of crashes at un-signalized intersections is 15.657 times higher in the absence of crosswalks compared to un-signalized intersections in which crosswalks are present. Conversely, signalized intersections related crashes were attributed to running the red light and pedestrians failing to obey traffic control devices.For the ordinal models for crashes at either intersections or mid-block locations, the results revealed that a reduction in the likelihood of severe injuries was associated with drivers being at fault, daytime, no aggressive driving related crashes and sober pedestrians. However, red light running related to intersection crashes, as well as pedestrians failing to yield to the right of way, and drivers under influence related to mid-block crashes were associated with high injury severity and an increase in the likelihood of severe injuries. The findings of this research and examination of the factors affecting pedestrians' crash likelihood and injury severity can lead to better crash mitigation strategies, countermeasures and policies that would alleviate this growing problem in Central Florida.
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Date Issued: 2017
Identifier: CFE0006566, ucf:51310
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006566

Title: Analysis of taxi drivers' driving behavior based on a driving simulator experiment.
Creator: Wu, Jiawei, Radwan, Essam, Abdel-Aty, Mohamed, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: Due to comfort, convenience, and flexibility, taxis become more and more prevalent in China, especially in large cities. According to a survey reported by Beijing Traffic Development Research Center, there were 696 million taxi person-rides in Beijing in 2011. However, many violations and road crashes that were related to taxi drivers occurred more frequently. The survey showed that there were a total of 17,242 taxi violations happened in Beijing in only one month in 2003, which accounted for...
Show moreDue to comfort, convenience, and flexibility, taxis become more and more prevalent in China, especially in large cities. According to a survey reported by Beijing Traffic Development Research Center, there were 696 million taxi person-rides in Beijing in 2011. However, many violations and road crashes that were related to taxi drivers occurred more frequently. The survey showed that there were a total of 17,242 taxi violations happened in Beijing in only one month in 2003, which accounted for 56% of all drivers' violations. Besides, taxi drivers also had a larger accident rate than other drivers, which showed that nearly 20% of taxi drivers had accidents each year. This study mainly focuses on investigating differences in driving behavior between taxi drivers and non-professional drivers.To examine the overall characteristics of taxi drivers and non-professional drivers, this study applied a hierarchical driving behavior assessment method to evaluate driving behaviors. This method is divided into three levels, including low-risk level, medium-risk level, and high-risk level. Low-risk level means the basic vehicle control. Medium-risk level refers to the vehicle dynamic decision. High-risk level represents the driver avoidance behavior when facing a potential crash.The Beijing Jiatong University (BJTU) driving simulator was applied to test different risk level scenarios which purpose is to find out the differences between taxi drivers and non-professional drivers on driving behaviors. Nearly 60 subjects, which include taxi drivers and non-professional drivers, were recruited in this experiment. Some statistical methods were applied to analyze the data and a logistic regression model was used to perform the high-risk level.The results showed that taxi drivers have more driving experience and their driving style is more conservative in the basic vehicle control level. For the car following behavior, taxi drivers have smaller following speed and larger gap compared to other drivers. For the yellow indication judgment behavior, although taxi drivers are slower than non-professional drivers when getting into the intersection, taxi drivers are more likely to run red light. For the lane changing behavior, taxi drivers' lane changing time is longer than others and lane changing average speed of taxi drivers is lower than other drivers.Another different behavior in high-risk level is that taxi drivers are more inclined to turn the steering wheel when facing a potential crash compared to non-professional drivers. However, non-professional drivers have more abrupt deceleration behaviors if they have the same situation.According to the experiment results, taxi drivers have a smaller crash rate compared to non-professional drivers. Taxi drivers spend a large amount of time on the road so that their driving experience must exceed that of non-professional drivers, which may bring them more skills. It is also speculated that because taxi drivers spend long hours on the job they probably have developed a more relaxed attitude about congestion and they are less likely to be candidates for road rage and over aggressive driving habits.
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Date Issued: 2014
Identifier: CFE0005561, ucf:50277
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005561

Title: An Analysis of the Protected-Permitted Left Turn at Intersections with a Varying Number of Opposing Through Lanes.
Creator: Navarro, Alexander, Radwan, Essam, Abou-Senna, Hatem, Abdel-Aty, Mohamed, University of Central Florida
Abstract / Description: The Flashing Yellow Arrow Left Turn signal is quickly becoming prominent in Central Florida as a new method of handling left turns at traffic signals. While the concept of a protected-permitted left turn is not groundbreaking, the departure from the typical display of a five-section signal head is, for this type of operation. The signal head introduced is a four-section head with a flashing yellow arrow between the yellow and green arrows. With this signal head quickly becoming the standard,...
Show moreThe Flashing Yellow Arrow Left Turn signal is quickly becoming prominent in Central Florida as a new method of handling left turns at traffic signals. While the concept of a protected-permitted left turn is not groundbreaking, the departure from the typical display of a five-section signal head is, for this type of operation. The signal head introduced is a four-section head with a flashing yellow arrow between the yellow and green arrows. With this signal head quickly becoming the standard, there is a need to re-evaluate the operational characteristics of the left turning vehicle and advance the knowledge of the significant parameters that may affect the ability for a driver to make a left turn at a signalized intersection. With previous research into the behavioral and operational characteristics of the flashing yellow arrow conducted, there is more information becoming available about the differences between this signal and the previously accepted method of allowing left turns at an intersection. The protected-permitted signal is typically displayed at an intersection with up to two through lanes and generally a protected signal is installed when the number of through lanes increases above two unless specific criteria is met. With the advent of larger arterials and more traffic on the highway networks, the push to operate these intersections at their maximum efficiency has resulted in more of these protected-permitted signals being present at these larger intersections, including the flashing yellow arrow.The core of the research that follows is a comparative analysis of the operation and parameters that affect the left turn movement of the intersection with larger geometry to that of the smaller geometry. The significant parameters of the left turn movement were examined through means of collecting, organizing and analyzing just over 68 hours of field data. This research details the determining of the significant parameters based on the generation of a simulation model of the protected left turn using Synchro, a traffic simulation package, and regression models using field driven data to determine the significant parameters for predicting the number of left turns that can be made in the permitted phase under specific operating conditions. Intuitively, there is an expectation that a larger intersection will not allow for as many permitted lefts as a smaller intersection with all conditions remaining the same. The conclusions drawn from this analysis provide the framework to understanding the similarities and the differences that are encountered when the intersection geometry differs and help to more efficiently manage traffic at signalized intersections.The work of this field promises to enhance the operations of the left turning movement for traffic control devices. With an understanding of the statistical models generated, a broader base of knowledge is gained as to the significant parameters that affect a driver's ability to make the left turn. A discussion of the statistical differences and between the models generated from the small and large geometry intersections is critical to drive further research into standards being developed for the highway transportation network and the treatment of these large signalized intersections. The exploration of specific parameters to predict the number of permitted left turns will yield results as to if there is more to be considered with larger intersections moving forward as they become a standard sight on the roadway network.
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Date Issued: 2014
Identifier: CFE0005387, ucf:50440
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005387

Title: TRAFFIC CONFLICT ANALYSIS UNDER FOG CONDITIONS USING COMPUTER SIMULATION.
Creator: Zhang, Binya, Radwan, Essam, Abdel-Aty, Mohamed, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: The weather condition is a crucial influence factor on road safety issues. Fog is one of the most noticeable weather conditions, which has a significant impact on traffic safety. Such condition reduces the road's visibility and consequently can affect drivers' vision, perception, and judgments. The statistical data shows that many crashes are directly or indirectly caused by the low-visibility weather condition. Hence, it is necessary for road traffic engineers to study the relationship of...
Show moreThe weather condition is a crucial influence factor on road safety issues. Fog is one of the most noticeable weather conditions, which has a significant impact on traffic safety. Such condition reduces the road's visibility and consequently can affect drivers' vision, perception, and judgments. The statistical data shows that many crashes are directly or indirectly caused by the low-visibility weather condition. Hence, it is necessary for road traffic engineers to study the relationship of road traffic accidents and their influence factors. Among these factors, the traffic volume and the speed limits in poor visibility areas are the primary reasons that can affect the types and occurring locations of road accidents.In this thesis, microscopic traffic simulation, through the use of VISSIM software, was used to study the road safety issue and its influencing factors due to limited visibility. A basic simulation model was built based on previously collected field data to simulate Interstate 4 (I-4)'s environment, geometry characteristics, and the basic traffic volume composition conditions. On the foundation of the basic simulation model, an experimental model was built to study the conflicts' types and distribution places under several different scenarios. Taking into consideration the entire 4-mile study area on I-4, this area was divided into 3 segments: section 1 with clear visibility, fog area of low visibility, and section 2 with clear visibility. Lower speed limits in the fog area, which were less than the limits in no-fog areas, were set to investigate the different speed limits' influence on the two main types of traffic conflicts: lane-change conflicts and rear-end conflicts. The experimental model generated several groups of traffic trajectory data files. The vehicle conflicts data were stored in these trajectory data files which, contains the conflict locations' coordinates, conflict time, time-to-conflict, and post-encroachment-time among other measures. The Surrogate Safety Assessment Model (SSAM), developed by the Federal Highway Administration, was applied to analyze these conflict data.From the analysis results, it is found that the traffic volume is an important factor, which has a large effect on the number of conflicts. The number of lane-change and rear-end conflicts increases along with the traffic volume growth. Another finding is that the difference between the speed limits in the fog area and in the no-fog areas is another significant factor that impacts the conflicts' frequency. Larger difference between the speed limits in two nearing road sections always leads to more accidents due to the inadequate reaction time for vehicle drivers to brake in time. And comparing to the scenarios that with the reduced speed limits in the low visibility zone, the condition that without the reduced speed limit has higher conflict number, which indicates that the it is necessary to put a lower speed limit in the fog zone which has a lower visibility. The results of this research have a certain reference value for studying the relationship between the road traffic conflicts and the impacts of different speed limits under fog condition. Overall, the findings of this research suggest follow up studies to further investigate possible relationships between conflicts as observed by simulation models and reported crashes in fog areas.
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Date Issued: 2015
Identifier: CFE0005747, ucf:50104
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005747

Title: Evaluating the Effectiveness of Conversion of Traditional Five Section Head Signal to Flashing Yellow Arrow (FYA) Signal.
Creator: Almoshaogeh, Meshal, Radwan, Essam, Abdel-Aty, Mohamed, Abou-Senna, Hatem, University of Central Florida
Abstract / Description: In the United States, there are two schemes of operating traffic signal controls for permitted protected left turns (PPLT) namely the traditional five-section head system (known as Dog-House) and the flashing yellow arrow system (FYA). Past studies have agreed that these controls lead to decrease the average delay per left turn vehicle, decrease the protected green time, increase the left turn capacity, and enhance the intersection overall operation.The flashing yellow arrow (FYA) has been...
Show moreIn the United States, there are two schemes of operating traffic signal controls for permitted protected left turns (PPLT) namely the traditional five-section head system (known as Dog-House) and the flashing yellow arrow system (FYA). Past studies have agreed that these controls lead to decrease the average delay per left turn vehicle, decrease the protected green time, increase the left turn capacity, and enhance the intersection overall operation.The flashing yellow arrow (FYA) has been approved by the Federal Highway Administration as the national standard for the PPLT operations at signalized intersections. So, the Florida Department of Transportation also approved this new system and they are extensively replacing the traditional system with the new system on the area of Central Florida (Lin, et al, 2010). Both these systems have been used for a long time and there are some studies that evaluated these systems but there are limited number of projects that evaluated and/or compared between the two PPLT systems from the operational perspective.The main goal of this research is to study the characteristics of traffic operations and evaluate the effectiveness of the conversion from five-section head signal to the FYA treatments at 13 intersections located in Orlando, Florida. To reach this goal, detailed data collection efforts were conducted at 13 selected intersections in the central Florida area and appropriate statistical tests were conducted using the Minitab 17 Software. Statistical tests were attempted to fit different new regression models that correlate delay and left turn volumes as response variables against a set of independent variables that included permitted green time, opposing volume, percent of trucks, time gaps, speed, and land use type. In addition to fitting the data to regression models, these models were also analyzed for the purpose of detecting any significant differences between the five-section head treatment and FYA treatment.The statistical differences of converting the five-section head system to FYA system were discussed. The results in this thesis agreed with some of the previous studies and did not agree with others. In general, the flashing yellow arrow system was found to enhance the intersection operation, increase the number of left turn vehicles, and reduce the delay. Also, some suggestions and recommendations were made based on this study results.
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Date Issued: 2014
Identifier: CFE0005296, ucf:50570
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005296

Title: Performance Predication Model for Advance Traffic Control System (ATCS) using field data.
Creator: Mirza, Masood, Radwan, Essam, Abou-Senna, Hatem, Abdel-Aty, Mohamed, Zheng, Qipeng, University of Central Florida
Abstract / Description: Reductions in capital expenditure revenues have created greater demands from users for quality service from existing facilities at lower costs forcing agencies to evaluate the performance of projects in more comprehensive and "greener" ways. The use of Adaptive Traffic Controls Systems (ATCS) is a step in the right direction by enabling practitioners and engineers to develop and implement traffic optimization strategies to achieve greater capacity out of the existing systems by optimizing...
Show moreReductions in capital expenditure revenues have created greater demands from users for quality service from existing facilities at lower costs forcing agencies to evaluate the performance of projects in more comprehensive and "greener" ways. The use of Adaptive Traffic Controls Systems (ATCS) is a step in the right direction by enabling practitioners and engineers to develop and implement traffic optimization strategies to achieve greater capacity out of the existing systems by optimizing traffic signal based on real time traffic demands and flow pattern. However, the industry is lagging in developing modeling tools for the ATCS which can predict the changes in MOEs due to the changes in traffic flow (i.e. volume and/or travel direction) making it difficult for the practitioners to measure the magnitude of the impacts and to develop an appropriate mitigation strategy. The impetus of this research was to explore the potential of utilizing available data from the ATCS for developing prediction models for the critical MOEs and for the entire intersection. Firstly, extensive data collections efforts were initiated to collect data from the intersections in Marion County, Florida. The data collected included volume, geometry, signal operations, and performance for an extended period. Secondly, the field data was scrubbed using macros to develop a clean data set for model development. Thirdly, the prediction models for the MOEs (wait time and queue) for the critical movements were developed using General Linear Regression Modeling techniques and were based on Poisson distribution with log linear function. Finally, the models were validated using the data collected from the intersections within Orange County, Florida. Also, as a part of this research, an Intersection Performance Index (IPI) model, a LOS prediction model for the entire intersection, was developed. This model was based on the MOEs (wait time and queue) for the critical movements.In addition, IPI Thresholds and corresponding intersection capacity designations were developed to establish level of service at the intersection. The IPI values and thresholds were developed on the same principles as Intersection Capacity Utilization (ICU) procedures, tested, and validated against corresponding ICU values and corresponding ICU LOS.
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Date Issued: 2018
Identifier: CFE0007055, ucf:51975
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007055

Title: Warrants for Right-Turn Flashing Yellow Arrow Signal Phases.
Creator: Alfawzan, Mohammed, Radwan, Ahmed, Eluru, Naveen, Abou-Senna, Hatem, Zheng, Qipeng, University of Central Florida
Abstract / Description: The right-turn flashing yellow arrow (FYA) signal phasing is a new signal practice in the United States. The Manual on Uniform Traffic Control Devices MUTCD (2009) allocates a signal phasing section for the right-turn FYA, which requires a four-section head FYA signal. It supports multiple phases' indications that guide the motorist through permissive, protected, and/or permissive/protected phases. For this dissertation, I investigated three permissive right-turn FYA signal phases in various...
Show moreThe right-turn flashing yellow arrow (FYA) signal phasing is a new signal practice in the United States. The Manual on Uniform Traffic Control Devices MUTCD (2009) allocates a signal phasing section for the right-turn FYA, which requires a four-section head FYA signal. It supports multiple phases' indications that guide the motorist through permissive, protected, and/or permissive/protected phases. For this dissertation, I investigated three permissive right-turn FYA signal phases in various traffic conditions and signal timing circumstances. The first permissive right-turn FYA signal phase is the tight-turn on impeding through (RTOIT) taking place during the cross-street through traffic movement. The second permissive right-turn FYA signal phase occurs during the opposing left-turn approach movement and so is called the right-turn on impeding left (RTOIL). The third permissive right-turn phase is a right-turn on through green impeded only by the side street pedestrians called the right-turn on adjacent through (RTOAT). I aimed to develop warrants leading to efficient implementation of permissive right-turn FYA signal phases based on microsimulation analysis. I developed multinomial logit models to establish a decision support system that predicts the efficiency attributes of the permissive right-turn FYA signal phases.
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Date Issued: 2019
Identifier: CFE0007883, ucf:52801
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007883

Title: Multi-Objective Optimization for Construction Equipment Fleet Selection and Management In Highway Construction Projects Based on Time, Cost, and Quality Objectives.
Creator: Shehadeh, Ali, Tatari, Omer, Al-Deek, Haitham, Abou-Senna, Hatem, Flitsiyan, Elena, University of Central Florida
Abstract / Description: The sector of highway construction shares approximately 11% of the total construction industry in the US. Construction equipment can be considered as one of the primary reasons this industry has reached such a significant level, as it is considered an essential part of the highway construction process during highway project construction. This research addresses a multi-objective optimization mathematical model that quantifies and optimize the key parameters for excavator, truck, and motor...
Show moreThe sector of highway construction shares approximately 11% of the total construction industry in the US. Construction equipment can be considered as one of the primary reasons this industry has reached such a significant level, as it is considered an essential part of the highway construction process during highway project construction. This research addresses a multi-objective optimization mathematical model that quantifies and optimize the key parameters for excavator, truck, and motor-grader equipment to minimize time and cost objective functions. The model is also aimed to maintain the required level of quality for the targeted construction activity. The mathematical functions for the primary objectives were formulated and then a genetic algorithm-based multi-objective was performed to generate the time-cost Pareto trade-offs for all possible equipment combinations using MATLAB software to facilitate the implementation. The model's capabilities in generating optimal time and cost trade-offs based on optimized equipment number, capacity, and speed to adapt with the complex and dynamic nature of highway construction projects are demonstrated using a highway construction case study. The developed model is a decision support tool during the construction process to adapt with any necessary changes into time or cost requirements taking into consideration environmental, safety and quality aspects. The flexibility and comprehensiveness of the proposed model, along with its programmable nature, make it a powerful tool for managing construction equipment, which will help saving time and money within the optimal quality margins. Also, this environmentally friendly decision-support tool model provided optimal solutions that help to reduce the CO2 emissions reducing the ripple effects of targeted highway construction activities on the global warming phenomenon. The generated optimal solutions offered considerable time and cost savings.
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Date Issued: 2019
Identifier: CFE0007863, ucf:52800
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007863

Title: MULTI-OBJECTIVE OPTIMIZATION FOR HEAVY EARTHMOVING CONSTRUCTION EQUIPMENT MANAGEMENT BASED ON TIME, COST, AND POLLUTANT EMISSIONS.
Creator: Alshboul, Odey, Tatari, Omer, Al-Deek, Haitham, Abou-Senna, Hatem, Awad, Amro, University of Central Florida
Abstract / Description: Earthmoving activity is considered a significant activity in the construction project. The cost of earthmoving activity in the construction projects in some cases reaches about 30% of the overall cost of the project. Moreover, heavy equipment selection needs to be utilized in this activity, such as trucks and excavators. Such equipment emits a huge amount of carbon that has a negative effect on environmental dimensions. A mathematical model to optimize all design variables (i.e., capacity,...
Show moreEarthmoving activity is considered a significant activity in the construction project. The cost of earthmoving activity in the construction projects in some cases reaches about 30% of the overall cost of the project. Moreover, heavy equipment selection needs to be utilized in this activity, such as trucks and excavators. Such equipment emits a huge amount of carbon that has a negative effect on environmental dimensions. A mathematical model to optimize all design variables (i.e., capacity, number, and speed) related to this equipment is urgently required to prevent these negative impacts. The proposed model offers a genetic algorithm-based optimization technique for earthmoving activity. The model has four main phases: (1) define all related decision variables for earthmoving equipment, (2) detect all related constraints that impact the optimization model, (3) derive the mathematical optimization model, and (4) apply the multi-objective genetic algorithms. The optimization approach is utilized to minimize the cost and duration of the earthmoving activity, along with reducing the carbon emissions and fuel consumption. A case study is applied to test and validate the addressed model. Optimization outputs have proven the model efficiency in saving substantial cost and time compared to the actual results. The results of the case study show that the innovative and original contribution of the created mathematical optimization model. These unique and new competencies are anticipated to support contractors and construction management engineers to minimize time and cost associated with earthmoving activities.
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Date Issued: 2019
Identifier: CFE0007598, ucf:52518
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007598

Title: Field Evaluation of Insync Adaptive Traffic Signal Control System in Multiple Environments Using Multiple Approaches.
Creator: Shafik, Md Shafikul Islam, Radwan, Essam, Abou-Senna, Hatem, Eluru, Naveen, University of Central Florida
Abstract / Description: Since the beginning of signalization of intersections, the management of traffic congestion is one of most critical challenges specifically for the city and urbanized area. Almost all the municipal agencies struggle to manage the perplexities associated with traffic congestion or signal control. The Adaptive Traffic Control System (ATCS), an advanced and major technological component of the Intelligent Transportation Systems (ITS) is considered the most dynamic and real-time traffic...
Show moreSince the beginning of signalization of intersections, the management of traffic congestion is one of most critical challenges specifically for the city and urbanized area. Almost all the municipal agencies struggle to manage the perplexities associated with traffic congestion or signal control. The Adaptive Traffic Control System (ATCS), an advanced and major technological component of the Intelligent Transportation Systems (ITS) is considered the most dynamic and real-time traffic management technology and has potential to effectively manage rapidly varying traffic flow relative to the current state-of-the-art traffic management practices.InSync ATCS is deployed in multiple states throughout the US and expanding on a large scale. Although there had been several 'Measure of Effectiveness' studies performed previously, the performance of InSync is not unquestionable especially because the previous studies failed to subject for multiple environments, approaches, and variables. Most studies are accomplished through a single approach using simple/na(&)#239;ve before-after method without any control group/parameter. They also lacked ample statistical analysis, historical, maturation and regression artifacts. An attempt to evaluate the InSync ATCS in varying conditions through multiple approaches was undertaken for the SR-434 and Lake Underhill corridor in Orange County, Florida. A before-after study with an adjacent corridor as control group and volume as a control parameter has been performed where data of multiple variables were collected by three distinct procedures. The average/floating-car method was utilized as a rudimentary data collection process and 'BlueMac' and 'InSync' system database was considered as secondary data sources. Data collected for three times a day for weekdays and weekends before and after the InSync ATCS was deployed.Results show variation in both performance and scale. It proved ineffective in some of the cases, especially for the left turns, total intersection queue/delay and when the intersection volumes approach capacity. The results are verified through appropriate statistical analysis.
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Date Issued: 2017
Identifier: CFE0006915, ucf:51687
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006915

Title: Microscopic Assessment of Transportation Emissions on Limited Access Highways.
Creator: Abou-Senna, Hatem, Radwan, Ahmed, Abdel-Aty, Mohamed, Al-Deek, Haitham, Cooper, Charles, Johnson, Mark, University of Central Florida
Abstract / Description: On-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have...
Show moreOn-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have estimated emissions using one average speed and volume on a long stretch of roadway. With MOVES, there is an opportunity for higher precision and accuracy. Integrating a microscopic traffic simulation model (such as VISSIM) with MOVES allows one to obtain precise and accurate emissions estimates. The new United States Environmental Protection Agency (USEPA) mobile source emissions model, MOVES2010a (MOVES) can estimate vehicle emissions on a second-by-second basis creating the opportunity to develop new software (")VIMIS 1.0(") (VISSIM/MOVES Integration Software) to facilitate the integration process. This research presents a microscopic examination of five key transportation parameters (traffic volume, speed, truck percentage, road grade and temperature) on a 10-mile stretch of Interstate 4 (I-4) test bed prototype; an urban limited access highway corridor in Orlando, Florida. The analysis was conducted utilizing VIMIS 1.0 and using an advanced custom design technique; D-Optimality and I-Optimality criteria, to identify active factors and to ensure precision in estimating the regression coefficients as well as the response variable.The analysis of the experiment identified the optimal settings of the key factors and resulted in the development of Micro-TEM (Microscopic Transportation Emissions Meta-Model). The main purpose of Micro-TEM is to serve as a substitute model for predicting transportation emissions on limited access highways to an acceptable degree of accuracy in lieu of running simulations using a traffic model and integrating the results in an emissions model. Furthermore, significant emission rate reductions were observed from the experiment on the modeled corridor especially for speeds between 55 and 60 mph while maintaining up to 80% and 90% of the freeway's capacity. However, vehicle activity characterization in terms of speed was shown to have a significant impact on the emission estimation approach.Four different approaches were further examined to capture the environmental impacts of vehicular operations on the modeled test bed prototype. First, (at the most basic level), emissions were estimated for the entire 10-mile section (")by hand(") using one average traffic volume and average speed. Then, three advanced levels of detail were studied using VISSIM/MOVES to analyze smaller links: average speeds and volumes (AVG), second-by-second link driving schedules (LDS), and second-by-second operating mode distributions (OPMODE). This research analyzed how the various approaches affect predicted emissions of CO, NOx, PM and CO2. The results demonstrated that obtaining accurate and comprehensive operating mode distributions on a second-by-second basis improves emission estimates. Specifically, emission rates were found to be highly sensitive to stop-and-go traffic and the associated driving cycles of acceleration, deceleration, frequent braking/coasting and idling. Using the AVG or LDS approach may overestimate or underestimate emissions, respectively, compared to an operating mode distribution approach.Additionally, model applications and mitigation scenarios were examined on the modeled corridor to evaluate the environmental impacts in terms of vehicular emissions and at the same time validate the developed model (")Micro-TEM("). Mitigation scenarios included the future implementation of managed lanes (ML) along with the general use lanes (GUL) on the I-4 corridor, the currently implemented variable speed limits (VSL) scenario as well as a hypothetical restricted truck lane (RTL) scenario. Results of the mitigation scenarios showed an overall speed improvement on the corridor which resulted in overall reduction in emissions and emission rates when compared to the existing condition (EX) scenario and specifically on link by link basis for the RTL scenario.The proposed emission rate estimation process also can be extended to gridded emissions for ozone modeling, or to localized air quality dispersion modeling, where temporal and spatial resolution of emissions is essential to predict the concentration of pollutants near roadways.
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Date Issued: 2012
Identifier: CFE0004777, ucf:49788
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004777

VISSIM (4)	+ -
SSAM (2)	+ -
Signalized Intersections (2)	+ -
driving simulator (2)	+ -
Adaptive Traffic Control System (ATCS) (1)	+ -

Air Quality Impacts (1)	+ -
Average-car Method (1)	+ -
Before-after Study (1)	+ -
Blank out Signs (1)	+ -
BlueMAC (1)	+ -
CFI (1)	+ -
CO2 (1)	+ -
Carbon Dioxide (1)	+ -
Continuous Flow Intersection (1)	+ -
Custom Design (1)	+ -
D-Optimal (1)	+ -
DDI (1)	+ -
Delay. (1)	+ -
Dilemma and Option Zones (1)	+ -
Driving behavior (1)	+ -
Environmental Impacts (1)	+ -
FYA Signals (1)	+ -
Field Evaluation (1)	+ -
Five Section Head Signal (1)	+ -
Flashing Yellow Arrow (FYA) (1)	+ -
GHG (1)	+ -
Greenhouse Gas Emissions (1)	+ -
I-Optimal (1)	+ -
InSync (1)	+ -
Innovative Design (1)	+ -

Abou-Senna, Hatem (15)	+ -
University of Central Florida (15)	+ -
Radwan, Essam (11)	+ -
Abdel-Aty, Mohamed (10)	+ -
Al-Deek, Haitham (3)	+ -

Eluru, Naveen (3)	+ -
Alfawzan, Mohammed (2)	+ -
Almoshaogeh, Meshal (2)	+ -
Radwan, Ahmed (2)	+ -
Tatari, Omer (2)	+ -
Wu, Jiawei (2)	+ -
Zheng, Qipeng (2)	+ -
Alshboul, Odey (1)	+ -
Awad, Amro (1)	+ -
Bianco, Zainb (1)	+ -
Cooper, Charles (1)	+ -
Darius, Jenner (1)	+ -
Flitsiyan, Elena (1)	+ -
Johnson, Mark (1)	+ -
Mirza, Masood (1)	+ -
Navarro, Alexander (1)	+ -
Shafik, Md Shafikul Islam (1)	+ -
Shehadeh, Ali (1)	+ -
Zhang, Binya (1)	+ -

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