Charles E. Via Jr. Department of Civil and Environmental Engineering

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https://hdl.handle.net/10919/23747
The Charles E. Via, Jr. Department of Civil and Environmental Engineering, which is ranked in the top 10 accredited civil and environmental engineering departments by the US News and World Report survey, is one of the largest programs in the United States. The Department has 46 full-time faculty, 657 undergraduate, and 400 graduate students. Civil engineers are the principal designers, constructors, operators, and caretakers of many of the constructed facilities and systems that contribute to the high quality of life enjoyed in the United States. The Charles E. Via, Jr. Department of Civil and Environmental Engineering offers educational programs in all areas of civil engineering practice.

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Browsing Charles E. Via Jr. Department of Civil and Environmental Engineering by Author "Abbas, Montasir M."

Now showing 1 - 7 of 7
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    Access Control Design on Highway Interchanges
    Rakha, Hesham A.; Flintsch, Alejandra Medina; Arafeh, Mazen; Abdel-Salam, Abdel-Salam Gomaa; Dua, Dhruv; Abbas, Montasir M. (Virginia Center for Transportation Innovation and Research, 2008-01-01)
    The adequate spacing and design of access to crossroads in the vicinity of freeway ramps are critical to the safety and traffic operations of both the freeway and the crossroad. The research presented in this report develops a methodology to evaluate the safety impact of different access road spacing standards. The results clearly demonstrate the shortcomings of the AASHTO standards and the benefits of enhancing them. The models developed as part of this research were used to compute the crash rate associated with alternative section spacing. The study demonstrates that the models satisfied the statistical requirements and provide reasonable crash estimates. The results demonstrate an eight-fold decrease in the crash rate when the access road spacing increases from 0 to 300 m. An increase in the minimum spacing from 90 m (300 ft) to 180 m (600 ft) results in a 50 percent reduction in the crash rate. The models were used to develop lookup tables that quantify the impact of access road spacing on the expected number of crashes per unit distance. The tables demonstrate a decrease in the crash rate as the access road spacing increases. An attempt was made to quantify the safety cost of alternative access road spacing using a weighted average crash cost. The weighted average crash cost was computed considering that 0.6, 34.8, and 64.6 percent of the crashes were fatal, injury, and property damage crashes, respectively. These proportions were generated from the field observed data. The cost of each of these crashes was provided by VDOT as $3,760,000, $48,200, and $6,500 for fatal, injury, and property damage crashes, respectively. This provided an average weighted crash cost of $43,533. This average cost was multiplied by the number of crashes per mile to compute the cost associated with different access spacing scenarios. These costs can assist policy makers in quantifying the trade-offs of different access management regulations.
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    Air pollution perception in ten countries during the COVID-19 pandemic
    Lou, Baowen; Barbieri, Diego Maria; Passavanti, Marco; Hui, Cang; Gupta, Akshay; Hoff, Inge; Lessa, Daniela Antunes; Sikka, Gaurav; Chang, Kevin; Fang, Kevin; Lam, Louisa; Maharaj, Brij; Ghasemi, Navid; Qiao, Yaning; Adomako, Solomon; Mirhosseini, Ali Foroutan; Naik, Bhaven; Banerjee, Arunabha; Wang, Fusong; Tucker, Andrew; Liu, Zhuangzhuang; Wijayaratna, Kasun; Naseri, Sahra; Yu, Lei; Chen, Hao; Shu, Benan; Goswami, Shubham; Peprah, Prince; Hessami, Amir; Abbas, Montasir M.; Agarwal, Nithin (2021-06-21)
    As largely documented in the literature, the stark restrictions enforced worldwide in 2020 to curb the COVID-19 pandemic also curtailed the production of air pollutants to some extent. This study investigates the perception of the air pollution as assessed by individuals located in ten countries: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the USA. The perceptions towards air quality were evaluated by employing an online survey administered in May 2020. Participants (N = 9394) in the ten countries expressed their opinions according to a Likert-scale response. A reduction in pollutant concentration was clearly perceived, albeit to a different extent, by all populations. The survey participants located in India and Italy perceived the largest drop in the air pollution concentration; conversely, the smallest variation was perceived among Chinese and Norwegian respondents. Among all the demographic indicators considered, only gender proved to be statistically significant.
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    Effect of Curing on Mechanical Properties of Cement-Stabilized Coral Sand in Marine Environment
    Chen, Mingyuan; Geng, Jiuguang; Xiong, Haocheng; Shang, Tao; Xue, Cheng; Abbas, Montasir M. (Hindawi, 2020-07-22)
    The use of coral sand prepared from cement-stabilized materials can significantly reduce the cost, construction period, and damage to the environment caused by stone mining. The choice of water in mixing and curing the cement-stabilized materials on islands should be considered. Cement-stabilized coral sand was tested in three different preparation and maintenance systems in the marine environment. The compressive strength, weight change, and chloride ion concentration change in cement-stabilized coral sand with different cement content were measured after 7 d, 28 d, 60 d, and 90 d, respectively. The microstructure of specimens was observed by XRD and SEM. Results show that the compressive strength of specimens in the seawater mixing and seawater curing system developed 0.9 MPa faster than that in the fresh water mixing and curing system at an early stage. But the compressive strength of specimens in seawater mixing and seawater curing shrank later, being 0.5 MPa lower than that in fresh water mixing and curing. The cement content was positively correlated with the free chloride ion reaction and mass growth rate. For road construction on islands, the mixing and curing of cement-stabilized coral sand with seawater should be given priority in the early stage.
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    Evaluation of Traffic Responsive Control on the Reston Parkway Arterial Network
    Abbas, Montasir M.; Abdelaziz, Sherif (Virginia Center for Transportation Innovation and Research, 2009-02-01)
    Traffic responsive plan selection (TRPS) control is considered an effective operational mode in traffic signal systems. Its efficiency stems from the fact that it can capture variations in traffic patterns and switch timing plans based on existing traffic conditions. Most of the research performed to date has focused on either small traffic networks-with up to five intersections-or theoretical networks. Past research has also focused on the threshold mechanism implemented in the National Electrical Manufacturers Association (NEMA) traffic controllers. There is very limited research on the pattern-matching mechanism implemented in the 170 controllers. This report documents a new approach to generating traffic scenarios for large networks, addressing issues such as the unequal traffic distribution and the large combination of traffic movements from multiple intersections. This approach is based on the selection of significant critical movements controlling the network using statistical correlation analysis of actual detector data and the use of synthetic origin-destination analysis of the entire network. The proposed approach was applied in the design of the traffic responsive control mode for the Reston Parkway arterial network, which has 14 intersections. Detector data were used to validate the results of the proposed approach. The validation process showed that the traffic system was correctly modeled and sufficiently represented by the proposed approach. Multi-objective optimization was used to generate the final timing plans and the TRPS pattern-matching parameters. Simulation analysis revealed that implementation of the traffic responsive control mode in the Reston Parkway network can achieve an average delay reduction of 27 percent and an average stops reduction of 14 percent on weekends and an average delay reduction of 18 percent and an average stops reduction of 21 percent on regular week days. The methodology documented in this report should be followed to implement TRPS control on large arterials in an optimal and stable manner. Optimal and stable operation of TRPS could significantly reduce congestion while capitalizing on existing traffic control infrastructure with a 46:1 benefit-cost ratio.
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    Impact of COVID-19 pandemic on mobility in ten countries and associated perceived risk for all transport modes
    Barbieri, Diego Maria; Lou, Baowen; Passavanti, Marco; Hui, Cang; Hoff, Inge; Lessa, Daniela Antunes; Sikka, Gaurav; Chang, Kevin; Gupta, Akshay; Fang, Kevin; Banerjee, Arunabha; Maharaj, Brij; Lam, Louisa; Ghasemi, Navid; Naik, Bhaven; Wang, Fusong; Mirhosseini, Ali Foroutan; Naseri, Sahra; Liu, Zhuangzhuang; Qiao, Yaning; Tucker, Andrew; Wijayaratna, Kasun; Peprah, Prince; Adomako, Solomon; Yu, Lei; Goswami, Shubham; Chen, Hao; Shu, Benan; Hessami, Amir; Abbas, Montasir M.; Agarwal, Nithin; Rashidi, Taha Hossein (2021-02-01)
    The restrictive measures implemented in response to the COVID-19 pandemic have triggered sudden massive changes to travel behaviors of people all around the world. This study examines the individual mobility patterns for all transport modes (walk, bicycle, motorcycle, car driven alone, car driven in company, bus, subway, tram, train, airplane) before and during the restrictions adopted in ten countries on six continents: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the United States. This cross-country study also aims at understanding the predictors of protective behaviors related to the transport sector and COVID-19. Findings hinge upon an online survey conducted in May 2020 (N = 9,394). The empirical results quantify tremendous disruptions for both commuting and non-commuting travels, highlighting substantial reductions in the frequency of all types of trips and use of all modes. In terms of potential virus spread, airplanes and buses are perceived to be the riskiest transport modes, while avoidance of public transport is consistently found across the countries. According to the Protection Motivation Theory, the study sheds new light on the fact that two indicators, namely income inequality, expressed as Gini index, and the reported number of deaths due to COVID-19 per 100,000 inhabitants, aggravate respondents' perceptions. This research indicates that socio-economic inequality and morbidity are not only related to actual health risks, as well documented in the relevant literature, but also to the perceived risks. These findings document the global impact of the COVID-19 crisis as well as provide guidance for transportation practitioners in developing future strategies.
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    A Real-Time Safety-Based Optimal Velocity Model
    Abdelhalim, Awad; Abbas, Montasir M. (IEEE, 2022-01-31)
    Modeling safety-critical driver behavior at signalized intersections needs to account for the driver's planned decision process, where a driver executes a plan to avoid collision in multiple time steps. Such a process can be embedded in the Optimal Velocity Model (OVM) that traditionally assumes that drivers base their "mental intention" on a distance gap only. We propose and evaluate a data-driven OVM based on real-time inference of roadside traffic video data. First, we extract vehicle trajectory data from roadside traffic footage through our advanced video processing algorithm (VT-Lane) for a study site in Blacksburg, VA, USA. Vehicles engaged in car-following episodes are then identified within the extracted vehicle trajectories database, and the real-time time-to-collision (TTC) is calculated for all car-following instances. Then, we analyze the driver behavior to predict the shape of the underlying TTC-based desired velocity function. A clustering approach is used to assess car-following behavior heterogeneity and understand the reasons behind outlying driving behaviors at the intersection to design our model accordingly. The results of this assessment show that the calibrated TTC-based OVM can replicate the observed driving behavior by capturing the acceleration pattern with an error 20% lower than the gap distance-based OVM.
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    Survey data regarding perceived air quality in Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa, United States before and during Covid-19 restrictions
    Barbieri, Diego Maria; Lou, Baowen; Passavanti, Marco; Hui, Cang; Lessa, Daniela Antunes; Maharaj, Brij; Banerjee, Arunabha; Wang, Fusong; Chang, Kevin; Naik, Bhaven; Yu, Lei; Liu, Zhuangzhuang; Sikka, Gaurav; Tucker, Andrew; Mirhosseini, Ali Foroutan; Naseri, Sahra; Qiao, Yaning; Gupta, Akshay; Abbas, Montasir M.; Fang, Kevin; Ghasemi, Navid; Peprah, Prince; Goswami, Shubham; Hessami, Amir; Agarwal, Nithin; Lam, Louisa; Adomako, Solomon (Elsevier, 2020-10-01)
    The dataset deals with the air quality perceived by citizens before and during the enforcement of COVID-19 restrictions in ten countries around the world: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the United States. An online survey conveniently translated into Chinese, English, Italian, Norwegian, Persian, Portuguese collected information regarding the perceived quality of air pollution according to a Likert scale. The questionnaire was distributed between 11-05-2020 and 31-05-2020 and 9 394 respondents took part. Both the survey and the dataset (stored in a Microsoft Excel Worksheet) are available in a public repository. The collected data offer the people's subjective perspectives related to the objective improvement in air quality occurred during the COVID-19 restrictions. Furthermore, the dataset can be used for research studies involving the reduction in air pollution as experienced, to a different extent, by populations of all the ten countries.