Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013
A new methodology is introduced for project selection which explicitly addresses issues of achiev... more A new methodology is introduced for project selection which explicitly addresses issues of achieving maximized overall project benefits for a given budget level by controlling the associated total risk of expected project benefits at an acceptable lower bound level. The risk of project benefits is quantified by the covariance of total benefits that could be achieved from jointly implementing any two projects where each project maintains a range of possible benefits and corresponding probabilities of occurrences. The methodology contains two-stage optimizations. First, the Markowitz mean-variance model is employed to establish the acceptable lower bound limit of the total risk. Second, the conventionally accepted zero/one Knapsack model for project selection is augmented to incorporate the acceptable lower bound risk limit constraint established from the first stage optimization as one additional constraint. In this way, the overall benefits of projects selected for implementation could be maximized and the total risk of expected project benefits is minimized simultaneously. The proposed model is applied for a six-year state-wide Interstate highway programming and project selection. Comparisons are made in the consistency of projects selection results generated from the proposed model, the existing basic knapsack formulation, and current state highway programming practice.
In the ever-growing travel demand, traffic congestion on freeways and expressways recurs more fre... more In the ever-growing travel demand, traffic congestion on freeways and expressways recurs more frequently at a higher number of locations and for longer durations with added severity. This becomes especially true in large metropolitan areas. Particular to the urban areas, excessive crowdedness caused by inefficient traffic control also results in urban street networks operating in near or over-saturated conditions, leading to unpleasant travel experience due to long delays at intersections. As a consequence, the recurrent traffic congestion on roadway segments and vehicle delays at intersections inevitably compromise energy efficiency, traffic mobility improvement, safety enhancement, and environmental impacts mitigation. All too often, neither restraining travel demand nor expanding system capacity is desirable and practical. Conversely, effectively utilizing the capacity of the existing transportation system has been increasingly thought of as the solution to congestion relief. Wit...
This article contains data on research conducted in "A double standard model for allocating ... more This article contains data on research conducted in "A double standard model for allocating limited emergency medical service vehicle resources ensuring service reliability" (Liu et al., 2016) [1]. The crash counts were sorted out from comprehensive crash records of over one thousand major signalized intersections in the city of Chicago from 2004 to 2010. For each intersection, vehicular crashes were counted by crash severity levels, including fatal, injury Types A, B, and C for major, moderate, and minor injury levels, property damage only (PDO), and unknown. The crash data was further used to rank intersections by equivalent injury crash frequency. The top 200 intersections with the highest number of crash occurrences identified based on crash frequency- and severity-based scenarios are shared in this brief. The provided data would be a valuable source for research in urban traffic safety analysis and could also be utilized to examine the effectiveness of traffic safety ...
The Transportation Science and Logistics (TSL) Section Dissertation Prize Competition is the olde... more The Transportation Science and Logistics (TSL) Section Dissertation Prize Competition is the oldest and most prestigious competition for doctoral dissertations in the transportation science and logistics area. The 2004 TSL dissertation prize committee consisted of Professor Ravi Ahuja (University of Florida), Professor Amy Cohn (Michigan University), Professor Randy Hall (University of Southern California), Professor Mark Hickman (Arizona University), and Professor Patrick Jaillet (Massachusetts Institute of Technology). Eligible doctoral dissertations were those completed and submitted between June 1, 2003, and May 31, 2004, in the general area of transportation science and logistics. To be considered, a dissertation had to be nominated by the thesis supervisor. This year we received 16 nominations. In addition to the large number of submissions, the quality of the theses was outstanding. I would like to extend my sincere thanks to the committee members for the time, effort, and pr...
Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013
A new methodology is introduced for project selection which explicitly addresses issues of achiev... more A new methodology is introduced for project selection which explicitly addresses issues of achieving maximized overall project benefits for a given budget level by controlling the associated total risk of expected project benefits at an acceptable lower bound level. The risk of project benefits is quantified by the covariance of total benefits that could be achieved from jointly implementing any two projects where each project maintains a range of possible benefits and corresponding probabilities of occurrences. The methodology contains two-stage optimizations. First, the Markowitz mean-variance model is employed to establish the acceptable lower bound limit of the total risk. Second, the conventionally accepted zero/one Knapsack model for project selection is augmented to incorporate the acceptable lower bound risk limit constraint established from the first stage optimization as one additional constraint. In this way, the overall benefits of projects selected for implementation could be maximized and the total risk of expected project benefits is minimized simultaneously. The proposed model is applied for a six-year state-wide Interstate highway programming and project selection. Comparisons are made in the consistency of projects selection results generated from the proposed model, the existing basic knapsack formulation, and current state highway programming practice.
In the ever-growing travel demand, traffic congestion on freeways and expressways recurs more fre... more In the ever-growing travel demand, traffic congestion on freeways and expressways recurs more frequently at a higher number of locations and for longer durations with added severity. This becomes especially true in large metropolitan areas. Particular to the urban areas, excessive crowdedness caused by inefficient traffic control also results in urban street networks operating in near or over-saturated conditions, leading to unpleasant travel experience due to long delays at intersections. As a consequence, the recurrent traffic congestion on roadway segments and vehicle delays at intersections inevitably compromise energy efficiency, traffic mobility improvement, safety enhancement, and environmental impacts mitigation. All too often, neither restraining travel demand nor expanding system capacity is desirable and practical. Conversely, effectively utilizing the capacity of the existing transportation system has been increasingly thought of as the solution to congestion relief. Wit...
This article contains data on research conducted in "A double standard model for allocating ... more This article contains data on research conducted in "A double standard model for allocating limited emergency medical service vehicle resources ensuring service reliability" (Liu et al., 2016) [1]. The crash counts were sorted out from comprehensive crash records of over one thousand major signalized intersections in the city of Chicago from 2004 to 2010. For each intersection, vehicular crashes were counted by crash severity levels, including fatal, injury Types A, B, and C for major, moderate, and minor injury levels, property damage only (PDO), and unknown. The crash data was further used to rank intersections by equivalent injury crash frequency. The top 200 intersections with the highest number of crash occurrences identified based on crash frequency- and severity-based scenarios are shared in this brief. The provided data would be a valuable source for research in urban traffic safety analysis and could also be utilized to examine the effectiveness of traffic safety ...
The Transportation Science and Logistics (TSL) Section Dissertation Prize Competition is the olde... more The Transportation Science and Logistics (TSL) Section Dissertation Prize Competition is the oldest and most prestigious competition for doctoral dissertations in the transportation science and logistics area. The 2004 TSL dissertation prize committee consisted of Professor Ravi Ahuja (University of Florida), Professor Amy Cohn (Michigan University), Professor Randy Hall (University of Southern California), Professor Mark Hickman (Arizona University), and Professor Patrick Jaillet (Massachusetts Institute of Technology). Eligible doctoral dissertations were those completed and submitted between June 1, 2003, and May 31, 2004, in the general area of transportation science and logistics. To be considered, a dissertation had to be nominated by the thesis supervisor. This year we received 16 nominations. In addition to the large number of submissions, the quality of the theses was outstanding. I would like to extend my sincere thanks to the committee members for the time, effort, and pr...
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