Ahmed I . Z . Mohamed

Zagazig University, Construction Engineering and Utilities, Faculty Member

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Ahmed I. Z. Mohamed had a Bachelor's degree in Civil Engineering, with a general grade of "Excellent with Honor” from the Faculty of Engineering, Zagazig University, Egypt in May 2011. After that, he worked as a Demonstrator in the Construction and Utilities Engineering department at the Faculty of Engineering, Zagazig University, Egypt from Nov. 2011 to Oct. 2016.
In September 2016, he had a Master's degree in Engineering Science from the Department of Construction and Utilities Engineering, Faculty of Engineering, Zagazig University, Egypt. Then, he worked as a Lecturer assistant in the Construction and Utilities Engineering department at the Faculty of Engineering, Zagazig University, Egypt from Oct. 2016 to March 2021.
In April 2021, he had a Doctor's degree in Traffic and Transportation Engineering from the School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090, China. Then, he worked as an Assistant professor in the Construction and Utilities Engineering department at the Faculty of Engineering, Zagazig University, Egypt from April. 2016 to date.

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Papers by Ahmed I . Z . Mohamed

A Novel Methodology for Estimating the Capacity and Level of Service for the New Mega Elliptical Roundabout Intersection

Journal of Advanced Transportation

Mega elliptical roundabout is a new intersection on rural multilane highways. This intersection w... more Mega elliptical roundabout is a new intersection on rural multilane highways. This intersection was developed in a previous paper using simulation data, and the authors found that it is better than interchange (full cloverleaf) in most scenarios of traffic flow. Basically, there are no guidelines or procedures for designing mega elliptical roundabout in AASHTO Green Book, Federal Highway Administration guides, and Highway Capacity Manual. Thus, the purpose of this study is to analyze the traffic operation performance and propose a methodology for calculating the capacity of mega elliptical roundabout and also the level of service by gap acceptance theory. Moreover, this research studied the influence of different values of truck ratios and also different values of a major highway speed on geometric design and traffic operation performance for mega elliptical roundabout. To validate the thoroughness of the proposed methodology, VISSIM simulations were conducted. This research will as...

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Safety Performance Evaluation of the New Mega Elliptical Roundabout Interchanges Using the Surrogate Safety Assessment Model

Journal of Transportation Engineering, Part A: Systems, 2020

Mega elliptical roundabouts are considered a new kind of intersection and can be found on rural m... more Mega elliptical roundabouts are considered a new kind of intersection and can be found on rural multilane highways. Their form is that of an elongated ellipse. They combine the best advantages of an unconventional median U-turn intersection and roundabout. The purpose of this research is analyzing safety performance for mega elliptical roundabout interchange using the VISSIM software version 4.30 and the surrogate safety assessment model (SSAM) software version 3. This research also considered eight other interchange designs to compare them with the mega elliptical roundabout interchange. In total, 20 scenarios were analyzed using VISSIM version 4.30 then tested by SSAM software version 3. To compare the different interchanges in terms of the mean values of conflicts, the one-way analyses of variance (ANOVA) were conducted. Based on the research results, a mega elliptical roundabout interchange was one of the best interchanges studied in this research in relation to the frequency of conflicts as a total and the frequency of crossing conflicts.

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Mega elliptical roundabouts versus grade-separation interchange

Proceedings of the Institution of Civil Engineers - Transport, 2019

The mega elliptical roundabout is a new idea for intersections on the rural multilane highways in... more The mega elliptical roundabout is a new idea for intersections on the rural multilane highways in the form of an elongated ellipse. Basically, there are no procedures or guidelines for designing mega elliptical roundabout in the Highway Capacity Manual (HCM), Federal Highway Administration guides (FHWA) and AASHTO Green Book. So this research presents the best geometric design scenarios of mega elliptical roundabout intersections at various traffic flows for all intersection entrances. The basis for selecting the best scenarios is to achieve minimum delay time, minimum emissions, and minimum fuel consumption. This was studied at the intersection of six lane-divided highway with four lane-divided highway when the traffic enters from four approaches. Moreover, this research proposes the cases in which the mega elliptical roundabout is better than interchange (full cloverleaf), and suggests the best time to make a decision to change from mega elliptical roundabout to interchange (full cloverleaf). The study was conducted by using VISSIM software (version 10.00-02). In total, 1134 scenarios were analyzed.

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A Novel Methodology for Estimating the Capacity and Level of Service for the New Mega Elliptical Roundabout Intersection

Journal of Advanced Transportation, 2020

The mega elliptical roundabout is a new type for intersections on rural multilane highways in the... more The mega elliptical roundabout is a new type for intersections on rural multilane highways in the form of an elongated ellipse that combines the best functions of the roundabout and unconventional median U-turn (UMUT) intersection. This intersection was developed in a previous paper using simulation data and found that it is better than interchange (full cloverleaf) in most scenarios of traffic flow. Basically, there are no procedures or guidelines for designing the mega elliptical roundabout in the Highway Capacity Manual, Federal Highway Administration guides, and AASHTO green book. Thus, the purpose of this study is to analyze the traffic operations performance and propose a methodology for calculating the capacity of mega elliptical roundabout intersections and also the level of service by gap acceptance theory. Moreover, this research studied the influence of different values of truck ratios and also different values of a major highway speed on geometric design and traffic operations performance for the mega elliptical roundabout. To validate the thoroughness of the proposed methodology, VISSIM simulations were conducted. This research will assist practitioners in determining the appropriate geometric design, assessing mega elliptical roundabout intersections and making comparisons with other alternatives.

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Conference Presentations by Ahmed I . Z . Mohamed

Methodology for Estimating the Capacity and Level of Service for the Mega Roundabout Intersection

Transportation Research Board (TRB) 99th Annual Meeting, 2020

The mega roundabout is a new type of intersections on the rural multilane highways in the form of... more The mega roundabout is a new type of intersections on the rural multilane highways in the form of an elongated ellipse that combines the best features of the roundabout and unconventional MUT intersection. This intersection was developed in a previous paper using simulation data and found that it is better than interchange (full cloverleaf) in most scenarios of traffic flow. Basically, there are no procedures or guidelines for the mega roundabout design in the Highway Capacity Manual (HCM), Federal Highway Administration guides (FHWA) and AASHTO green book. So the purpose of this paper is to analyze the performance of traffic operations and to propose a methodology for estimating the capacity and level of service of the mega roundabout intersections by gap acceptance theory, to assist practitioners in determining the appropriate geometric design, assessment of mega roundabout intersections and to make comparisons with other alternatives. Explicit VISSIM simulations are conducted to validate the accuracy of the proposed methodology.

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A Novel Methodology for Estimating the Capacity and Level of Service for the New Mega Elliptical Roundabout Intersection

Journal of Advanced Transportation

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Safety Performance Evaluation of the New Mega Elliptical Roundabout Interchanges Using the Surrogate Safety Assessment Model

Journal of Transportation Engineering, Part A: Systems, 2020

Download

Mega elliptical roundabouts versus grade-separation interchange

Proceedings of the Institution of Civil Engineers - Transport, 2019

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A Novel Methodology for Estimating the Capacity and Level of Service for the New Mega Elliptical Roundabout Intersection

Journal of Advanced Transportation, 2020