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  Subjects -> TRANSPORTATION (Total: 141 journals)
    - AIR TRANSPORT (5 journals)
    - AUTOMOBILES (20 journals)
    - RAILROADS (4 journals)
    - ROADS AND TRAFFIC (4 journals)
    - SHIPS AND SHIPPING (20 journals)
    - TRANSPORTATION (88 journals)

TRANSPORTATION (88 journals)

Accident Analysis & Prevention     Partially Free   (Followers: 17)
AI & Society     Hybrid Journal   (Followers: 2)
Archives of Transport     Open Access   (Followers: 4)
Bitácora Urbano-Territorial     Open Access   (Followers: 2)
Cities in the 21st Century     Open Access   (Followers: 10)
Economics of Transportation     Partially Free   (Followers: 10)
EURO Journal of Transportation and Logistics     Hybrid Journal   (Followers: 4)
European Transport Research Review     Open Access   (Followers: 10)
Geosystem Engineering     Hybrid Journal   (Followers: 3)
IATSS Research     Open Access  
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 5)
IET Electrical Systems in Transportation     Hybrid Journal   (Followers: 6)
IET Intelligent Transport Systems     Hybrid Journal   (Followers: 4)
International Innovation – Transport     Open Access   (Followers: 2)
International Journal of Applied Logistics     Full-text available via subscription   (Followers: 4)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 4)
International Journal of Critical Infrastructure Protection     Hybrid Journal   (Followers: 5)
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 4)
International Journal of Electronic Transport     Hybrid Journal   (Followers: 2)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
International Journal of Intelligent Transportation Systems Research     Hybrid Journal   (Followers: 5)
International Journal of Micro-Nano Scale Transport     Full-text available via subscription   (Followers: 2)
International Journal of Mobile Communications     Hybrid Journal   (Followers: 7)
International Journal of Ocean Systems Management     Hybrid Journal   (Followers: 3)
International Journal of Physical Distribution & Logistics Management     Hybrid Journal   (Followers: 7)
International Journal of Services Technology and Management     Hybrid Journal   (Followers: 1)
International Journal of Sustainable Transportation     Hybrid Journal   (Followers: 4)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 13)
International Journal of Transportation Science and Technology     Full-text available via subscription   (Followers: 4)
International Journal of Vehicle Systems Modelling and Testing     Hybrid Journal   (Followers: 4)
International Journal of Vehicular Technology     Open Access   (Followers: 2)
Journal of Advanced Transportation     Hybrid Journal   (Followers: 10)
Journal of Modern Transportation     Full-text available via subscription   (Followers: 1)
Journal of Navigation     Hybrid Journal   (Followers: 37)
Journal of Sport & Social Issues     Hybrid Journal   (Followers: 8)
Journal of Sustainable Mobility     Full-text available via subscription  
Journal of the Transportation Research Forum     Open Access   (Followers: 4)
Journal of Transport & Health     Hybrid Journal   (Followers: 2)
Journal of Transport and Land Use     Open Access   (Followers: 9)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 6)
Journal of Transport Geography     Hybrid Journal   (Followers: 16)
Journal of Transport History     Full-text available via subscription   (Followers: 10)
Journal of Transport Literature     Open Access  
Journal of Transportation Safety & Security     Hybrid Journal   (Followers: 8)
Journal of Transportation Security     Hybrid Journal   (Followers: 2)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 13)
Journal of Transportation Technologies     Open Access   (Followers: 9)
Journal of Waterway Port Coastal and Ocean Engineering     Full-text available via subscription   (Followers: 6)
Les Dossiers du Grihl     Open Access  
Logistique & Management     Full-text available via subscription  
Mechatronics, Electrical Power, and Vehicular Technology     Open Access   (Followers: 1)
Modern Transportation     Open Access   (Followers: 2)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
Open Journal of Safety Science and Technology     Open Access   (Followers: 5)
Pervasive and Mobile Computing     Hybrid Journal   (Followers: 9)
Proceedings of the Institution of Mechanical Engineers Part F: Journal of Rail and Rapid Transit     Hybrid Journal   (Followers: 4)
PS: Political Science & Politics     Full-text available via subscription   (Followers: 20)
Public Transport     Hybrid Journal   (Followers: 8)
Recherche Transports Sécurité     Hybrid Journal   (Followers: 1)
Research in Transportation Business and Management     Partially Free   (Followers: 2)
Revista Transporte y Territorio     Open Access   (Followers: 1)
SourceOCDE Transports     Full-text available via subscription   (Followers: 1)
Sport, Education and Society     Hybrid Journal   (Followers: 11)
Sport, Ethics and Philosophy     Hybrid Journal   (Followers: 2)
Streetnotes     Open Access   (Followers: 2)
Synthesis Lectures on Mobile and Pervasive Computing     Full-text available via subscription   (Followers: 2)
Tire Science and Technology     Full-text available via subscription  
Transactions on Transport Sciences     Open Access   (Followers: 3)
Transport     Hybrid Journal   (Followers: 6)
Transport and Telecommunication Journal     Open Access   (Followers: 2)
Transport in Porous Media     Hybrid Journal   (Followers: 1)
Transport Reviews: A Transnational Transdisciplinary Journal     Hybrid Journal   (Followers: 5)
Transportation     Hybrid Journal   (Followers: 16)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 3)
Transportation Journal     Full-text available via subscription   (Followers: 5)
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 23)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 22)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 14)
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 27)
Transportation Science     Full-text available via subscription   (Followers: 14)
TRANSPORTES     Open Access   (Followers: 2)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 1)
Transportmetrica B : Transport Dynamics     Hybrid Journal  
Travel Behaviour and Society     Full-text available via subscription  
Travel Medicine and Infectious Disease     Hybrid Journal   (Followers: 2)
Urban, Planning and Transport Research     Open Access   (Followers: 3)
World Review of Intermodal Transportation Research     Hybrid Journal   (Followers: 3)
Транспортні системи та технології перевезень     Open Access  
Journal Cover Transportation Research Part B: Methodological
   [24 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0191-2615
     Published by Elsevier Homepage  [2575 journals]   [SJR: 3.08]   [H-I: 60]
  • A trial-and-error congestion pricing scheme for networks with elastic
           demand and link capacity constraints
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Bojian Zhou , Michiel Bliemer , Hai Yang , Jie He
      This paper proposes a combination of trial-and-error congestion pricing schemes that have been studied in the literature. It not only considers the minimization of the total system cost but also addresses the capacity constraints. A two-level iteration method is proposed for solving the hybrid problem, in which the approximate subgradient projection method is used for the outer level iteration phase, and the partial linearization method is used for the inner level iteration phase. We prove the convergence of the two-level iteration method, under the condition that the subproblem for the inner level iteration is only solved approximately, which makes the method efficient and practical. A numerical example is presented to illustrate the application of the two-level iteration method to the trial-and-error congestion pricing scheme.


      PubDate: 2014-12-14T02:59:10Z
       
  • Editorial Board
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71




      PubDate: 2014-12-10T02:58:42Z
       
  • Profit-based maritime container assignment models for liner shipping
           networks
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Shuaian Wang , Zhiyuan Liu , Michael G.H. Bell
      We propose the problem of profit-based container assignment (P-CA), in which the container shipment demand is dependent on the freight rate, similar to the “elastic demand” in the literature on urban transportation networks. The problem involves determining the optimal freight rates, the number of containers to transport and how to transport the containers in a liner shipping network to maximize the total profit. We first consider a tactical-level P-CA with known demand functions that are estimated based on historical data and formulate it as a nonlinear optimization model. The tactical-level P-CA can be used for evaluating and improving the container liner shipping network. We then address the operational-level P-CA with unknown demand functions, which aims to design a mechanism that adjusts the freight rates to maximize the profit. A theoretically convergent trial-and-error approach, and a practical trial-and-error approach, are developed. A numerical example is reported to illustrate the application of the models and approaches.


      PubDate: 2014-12-10T02:58:42Z
       
  • Optimal transit routing with partial online information
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Peng (Will) Chen , Yu (Marco) Nie
      This paper studies the routing strategy in a transit network with partial online information at stops. By partial online information, we mean that the arrival time of the incoming transit vehicles is available for a subset of the lines serving a stop. To cope with the partial information assumption, a new routing strategy is proposed and closed form formulae for computing expected waiting times and line boarding probabilities are derived. The proposed strategy unifies existing hyperpath-based transit route choice models that assume either no information or full information. Like many existing models, it ensures optimality when all information is available or the headway is exponentially distributed. The problem of determining the attractive set is discussed for each of the three information cases. In particular, a new heuristic algorithm is developed to generate the attractive set in the partial information case, which will always yield a solution no worse than that obtained without any information. The paper also reveals that, when information is available, an optimal hyperpath may contain cycles. Accordingly, the cause of such cycles is analyzed, and a sufficient condition that excludes cycles from optimal hyperpaths is proposed. Finally, numerical experiments are conducted to illustrate the impact of information availability on expected travel times and transit line load distributions. Among other findings, the results suggest that it is more useful to have information on faster lines than on slower lines.


      PubDate: 2014-12-06T02:50:54Z
       
  • A 3-step math heuristic for the static repositioning problem in
           bike-sharing systems
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Iris A. Forma , Tal Raviv , Michal Tzur
      Over the last few years, bike-sharing systems have emerged as a new mode of transportation in a large number of big cities worldwide. This new type of mobility mode is still developing, and many challenges associated with its operation are not well addressed yet. One such major challenge of bike-sharing systems is the need to respond to fluctuating demands for bicycles and for vacant lockers at each station, which directly influences the service level provided to its users. This is done using dedicated repositioning vehicles (light trucks) that are routed through the stations, loading and unloading bicycles to/from them. Performing this operation during the night when the demand in the system is negligible is referred to as the static repositioning problem. In this paper, we propose a 3-step mathematical programming based heuristic for the static repositioning problem. In the first step, stations are clustered according to geographic as well as inventory (of bicycles) considerations. In the second step the repositioning vehicles are routed through the clusters while tentative inventory decisions are made for each individual station. Finally, the original repositioning problem is solved with the restriction that traversal of the repositioning vehicles is allowed only between stations that belong to consecutive clusters according to the routes determined in the previous step, or between stations of the same cluster. In the first step the clusters are formed using a specialized saving heuristic. The last two steps are formulated as Mixed Integer Linear Programs and solved by a commercial solver. The method was tested on instances of up to 200 stations and three repositioning vehicles, and was shown to outperform a previous method suggested in the literature for the same problem.


      PubDate: 2014-12-06T02:50:54Z
       
  • Link-based day-to-day network traffic dynamics and equilibria
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Ren-Yong Guo , Hai Yang , Hai-Jun Huang , Zhijia Tan
      A general dynamical system model with link-based variables is formulated to characterize the processes of achieving equilibria from a non-equilibrium state in traffic networks. Several desirable properties of the dynamical system model are established, including the equivalence between its stationary state and user equilibrium, the invariance of its evolutionary trajectories, and the uniqueness and stability of its stationary points. Moreover, it is shown that not only a link-based version of two existing day-to-day traffic dynamics models but also two existing link-based dynamical system models of traffic flow are the special cases of the proposed model. The stabilities of stationary states of these special cases are also analyzed and discussed. In addition, an extension is made to the case with elastic demand. The study is helpful for better understanding the day-to-day adjustment mechanism of traffic flows in networks.


      PubDate: 2014-12-06T02:50:54Z
       
  • Entropy weighted average method for the determination of a single
           representative path flow solution for the static user equilibrium traffic
           assignment problem
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Amit Kumar , Srinivas Peeta
      The formulation of the static user equilibrium traffic assignment problem (UETAP) under some simplifying assumptions has a unique solution in terms of link flows but not in terms of path flows. Large variations are possible in the path flows obtained using different UETAP solution algorithms. Many transportation planning and management applications entail the need for path flows. This raises the issue of generating a meaningful path flow solution in practice. Past studies have sought to determine a single path flow solution using the maximum entropy concept. This study proposes an alternate approach to determine a single path flow solution that represents the entropy weighted average of the UETAP path flow solution space. It has the minimum expected Euclidean distance from all other path flow solution vectors of the UETAP. The mathematical model of the proposed entropy weighted average method is derived and its solution stability is proved. The model is easy to interpret and generalizes the proportionality condition of Bar-Gera and Boyce (1999). Results of numerical experiments using networks of different sizes suggest that the path flow solutions for the UETAP using the proposed method are about identical to those obtained using the maximum entropy approach. The entropy weighted average method requires low computational effort and is easier to implement, and can therefore serve as a potential alternative to the maximum entropy approach in practice.


      PubDate: 2014-12-06T02:50:54Z
       
  • Global optimization method for network design problem with stochastic user
           equilibrium
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Haoxiang Liu , David Z.W. Wang
      In this paper, we consider the continuous road network design problem with stochastic user equilibrium constraint that aims to optimize the network performance via road capacity expansion. The network flow pattern is subject to stochastic user equilibrium, specifically, the logit route choice model. The resulting formulation, a nonlinear nonconvex programming problem, is firstly transformed into a nonlinear program with only logarithmic functions as nonlinear terms, for which a tight linear programming relaxation is derived by using an outer-approximation technique. The linear programming relaxation is then embedded within a global optimization solution algorithm based on range reduction technique, and the proposed approach is proved to converge to a global optimum.


      PubDate: 2014-12-06T02:50:54Z
       
  • A tailored branch-and-price approach for a joint tramp ship routing and
           bunkering problem
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Qiang Meng , Shuaian Wang , Chung-Yee Lee
      This paper deals with a practical tramp ship routing problem while taking into account different bunker prices at different ports, which is called the joint tramp ship routing and bunkering (JSRB) problem. Given a set of cargoes to be transported and a set of ports with different bunker prices, the proposed problem determines how to route ships to carry the cargoes and the amount of bunker to purchase at each port, in order to maximize the total profit. After building an integer linear programming model for the JSRB problem, we propose a tailored branch-and-price (B&P) solution approach. The B&P approach incorporates an efficient method for obtaining the optimal bunkering policy and a novel dominance rule for detecting inefficient routing options. The B&P approach is tested with randomly generated large-scale instances derived from real-world planning problems. All of the instances can be solved efficiently. Moreover, the proposed approach for the JSRB problem outperforms the conventional sequential planning approach and can incorporate the prediction of future cargo demand to avoid making myopic decisions.


      PubDate: 2014-12-06T02:50:54Z
       
  • The kinematic wave model with finite decelerations: A social force
           car-following model approximation
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Rafael Delpiano , Jorge Laval , Juan Enrique Coeymans , Juan Carlos Herrera
      This paper derives a five-parameter social force car-following model that converges to the kinematic wave model with triangular fundamental diagram. Analytical solutions for vehicle trajectories are found for the lead-vehicle problem, which exhibit clockwise and counter-clockwise hysteresis depending on the model’s parameters and the lead vehicle trajectory. When coupled with a stochastic vehicle dynamics module, the model is able to reproduce periods and amplitudes of stop-and-go waves, as reported in the field. The model’s stability conditions are analysed and its trajectories are compared to real data.


      PubDate: 2014-12-01T02:50:25Z
       
  • Bidirectional pedestrian fundamental diagram
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Gunnar Flötteröd , Gregor Lämmel
      This article presents a new model of stationary bidirectional pedestrian flow. Starting out from microscopic first principles, a bidirectional fundamental diagram (FD) is derived that defines direction-specific flow rates as functions of direction-specific densities. The FD yields non-negative and bounded flows and guarantees that the instantaneous density changes that would result from these flows stay bounded between zero and jam density. In its minimal configuration, it uses just as many parameters as a unidirectional triangular FD: maximum walking speed, jam density, a collision avoidance parameter (from which the backward wave speed can be derived). A one-on-one mapping between the parameters guiding uni- and bidirectional pedestrian flows is proposed and both conceptually and empirically justified. Generalizations of the FD that maintain its desirable properties turn out to be straightforward by making its parameters density-dependent. The FD performs very well in comparisons against simulated and real data.


      PubDate: 2014-12-01T02:50:25Z
       
  • A reliability model for facility location design under imperfect
           information
    • Abstract: Publication date: Available online 26 November 2014
      Source:Transportation Research Part B: Methodological
      Author(s): Lifen Yun , Yong Qin , Hongqiang Fan , Changxu Ji , Xiaopeng Li , Limin Jia
      This paper aims to propose a modeling framework for reliable facility location design under imperfect information, i.e., when customers do not know the real-time information of facility disruption states. We consider a realistic “trial-and-error” strategy for a customer to visit facilities without knowing their states until arriving at this facility; i.e., a customer keeps trying a number of pre-assigned facilities until she acquires the service or is forced to give up trying. The research problem is to determine the best facility location that minimizes the total system cost, including initial facility investment and expected long-term operational cost from transportation and loss of service, when facilities are subject to probabilistic disruptions and customers use the trial-and-error strategy. This problem is formulated into a compact integer program (IP), and we develop a Lagrangian relaxation algorithm to solve it. A set of case studies are conducted to test the performance of the proposed algorithm, and illustrate the applicability of the proposed model. The results reveal a number of interesting insights into the system design, including the significance of multi-level customer-facility assignments and the existence of a robust system design against variation of the loss-of-service penalty.


      PubDate: 2014-11-27T02:50:02Z
       
  • The load-dependent vehicle routing problem and its pick-up and delivery
           extension
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Emmanouil E. Zachariadis , Christos D. Tarantilis , Chris T. Kiranoudis
      The present paper examines a Vehicle Routing Problem (VRP) of major practical importance which is referred to as the Load-Dependent VRP (LDVRP). LDVRP is applicable for transportation activities where the weight of the transported cargo accounts for a significant part of the vehicle gross weight. Contrary to the basic VRP which calls for the minimization of the distance travelled, the LDVRP objective is aimed at minimizing the total product of the distance travelled and the gross weight carried along this distance. Thus, it is capable of producing sensible routing plans which take into account the variation of the cargo weight along the vehicle trips. The LDVRP objective is closely related to the total energy requirements of the vehicle fleet, making it a credible alternative when the environmental aspects of transportation activities are examined and optimized. A novel LDVRP extension which considers simultaneous pick-up and delivery service is introduced, formulated and solved for the first time. To deal with large-scale instances of the examined problems, we propose a local-search algorithm. Towards an efficient implementation, the local-search algorithm employs a computational scheme which calculates the complex weighted-distance objective changes in constant time. Solution results are presented for both problems on a variety of well-known test cases demonstrating the effectiveness of the proposed solution approach. The structure of the obtained LDVRP and VRP solutions is compared in pursuit of interesting conclusions on the relative suitability of the two routing models, when the decision maker must deal with the weighted distance objective. In addition, results of a branch-and-cut procedure for small-scale instances of the LDVRP with simultaneous pick-ups and deliveries are reported. Finally, extensive computational experiments have been performed to explore the managerial implications of three key problem characteristics, namely the deviation of customer demands, the cargo to tare weight ratio, as well as the size of the available vehicle fleet.


      PubDate: 2014-11-27T02:50:02Z
       
  • Microscopic driving theory with oscillatory congested states: Model and
           empirical verification
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Junfang Tian , Martin Treiber , Shoufeng Ma , Bin Jia , Wenyi Zhang
      The essential distinction between the Fundamental Diagram Approach (FDA) and Kerner’s three-phase theory (KTPT) is the existence of a unique gap–speed (or flow–density) relationship in the former class. In order to verify this relationship, empirical data are analyzed with the following findings: (1) linear relationship between the actual space gap and speed can be identified when the speed difference between vehicles approximates zero; (2) vehicles accelerate or decelerate around the desired space gap most of the time. To explain these phenomena, we propose that, in congested traffic flow, the space gap between two vehicles will oscillate around the desired space gap in the deterministic limit. This assumption is formulated in terms of a cellular automaton. In contrast to FDA and KTPT, the new model does not have any congested steady-state solution. Simulations under periodic and open boundary conditions reproduce the empirical findings of KTPT. Calibrating and validating the model to detector data produces results that are better than that of previous studies.


      PubDate: 2014-11-27T02:50:02Z
       
  • Parking search equilibrium on a network
    • Abstract: Publication date: Available online 22 November 2014
      Source:Transportation Research Part B: Methodological
      Author(s): Stephen D. Boyles , Shoupeng Tang , Avinash Unnikrishnan
      This paper describes an equilibrium formulation for incorporating parking search into traffic network assignment models. The proposed model allows general network topologies and reflects uncertainty related to parking availability, including the possibility of cycling behavior as drivers search for parking. The equilibrium framework represents the mutual dependence between the probabilities of finding parking at different locations and the search processes employed by drivers to minimize total expected journey time (or cost). In this framework, network loading is represented by a system of nonlinear flow conservation networks, and feasibility and uniqueness issues are discussed. The equilibrium problem is formulated as a variational inequality and a convex combinations heuristic is proposed. Numerical results show that neglecting parking search can substantially underestimate network flows, and quantitatively demonstrate the relationship between parking duration effects and the cost of time spent walking relative to driving, and the expected driving and walking times.


      PubDate: 2014-11-23T02:49:34Z
       
  • Editorial Board
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70




      PubDate: 2014-11-19T02:49:08Z
       
  • Variable speed limit control for steady and oscillatory queues at fixed
           freeway bottlenecks
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Danjue Chen , Soyoung Ahn , Andreas Hegyi
      New variable speed limit (VSL) schemes are developed based on the Kinematic Wave theory to increase freeway bottleneck discharge rates under two scenarios: (i) steady queue and (ii) oscillatory queue. The key principle is to impose VSL control some distance upstream of a bottleneck to starve the inflow to the bottleneck and dissipate the queue. Once the queue near the bottleneck vanishes, another less restrictive VSL is imposed upstream to (i) resolve the heavy queue generated by the first VSL and (ii) regulate the inflow to the bottleneck to sustain the stable maximum bottleneck discharge rate and prevent traffic breakdown. Several strategies are developed for each scenario ranging from the simplest strategy that maximizes the delay saving to more sophisticated strategies for upstream queue management. An analysis of the model parameters suggests that a wide range of the first speed limit (to clear the queue around the bottleneck) can be imposed to realize significant delay savings.


      PubDate: 2014-11-19T02:49:08Z
       
  • Optimizing intersections
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Ruth Evers , Stef Proost
      In this paper we optimize the regulation of an intersection of two routes connecting one origin–destination pair and study the effects of priority rules, traffic lights and tolls. We show that when the intersection is regulated by a priority rule the optimal policy is generally to block one of the two routes. When the intersection is regulated by traffic lights, it can only be optimal to leave both routes open when both routes are subject to congestion or if a toll is levied.


      PubDate: 2014-11-19T02:49:08Z
       
  • Probe vehicle data sampled by time or space: Consistent travel time
           allocation and estimation
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Erik Jenelius , Haris N. Koutsopoulos
      A characteristic of low frequency probe vehicle data is that vehicles traverse multiple network components (e.g., links) between consecutive position samplings, creating challenges for (i) the allocation of the measured travel time to the traversed components, and (ii) the consistent estimation of component travel time distribution parameters. This paper shows that the solution to these problems depends on whether sampling is based on time (e.g., one report every minute) or space (e.g., one every 500m). For the special case of segments with uniform space-mean speeds, explicit formulae are derived under both sampling principles for the likelihood of the measurements and the allocation of travel time. It is shown that time-based sampling is biased towards measurements where a disproportionally long time is spent on the last segment. Numerical experiments show that an incorrect likelihood formulation can lead to significantly biased parameter estimates depending on the shapes of the travel time distributions. The analysis reveals that the sampling protocol needs to be considered in travel time estimation using probe vehicle data.


      PubDate: 2014-11-19T02:49:08Z
       
  • Determining optimal frequency and vehicle capacity for public transit
           routes: A generalized newsvendor model
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Avi Herbon , Yuval Hadas
      The level of service on public transit routes is very much affected by the frequency and vehicle capacity. The combined values of these variables contribute to the costs associated with route operations as well as the costs associated with passenger comfort, such as waiting and overcrowding. The new approach to the problem that we introduce combines both passenger and operator costs within a generalized newsvendor model. From the passenger perspective, waiting and overcrowding costs are used; from the operator’s perspective, the costs are related to vehicle size, empty seats, and lost sales. Maximal passenger average waiting time as well as maximal vehicle capacity are considered as constraints that are imposed by the regulator to assure a minimal public transit service level or in order to comply with other regulatory considerations. The advantages of the newsvendor model are that (a) costs are treated as shortages (overcrowding) and surpluses (empty seats); (b) the model presents simultaneous optimal results for both frequency and vehicle size; (c) an efficient and fast algorithm is developed; and (d) the model assumes stochastic demand, and is not restricted to a specific distribution. We demonstrate the usefulness of the model through a case study and sensitivity analysis.


      PubDate: 2014-11-19T02:49:08Z
       
  • Train design and routing optimization for evaluating criticality of
           freight railroad infrastructures
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Abdullah A. Khaled , Mingzhou Jin , David B. Clarke , Mohammad A. Hoque
      Freight transportation by railroads is an integral part of the U.S. economy. Identifying critical rail infrastructures can help stakeholders prioritize protection initiatives or add necessary redundancy to maximize rail network resiliency. The criticality of an infrastructure element, link or yard, is based on the increased cost (delay) incurred when that element is disrupted. An event of disruption can cause heavy congestion so that the capacity at links and yards should be considered when freight is re-routed. This paper proposes an optimization model for making-up and routing of trains in a disruptive situation to minimize the system-wide total cost, including classification time at yards and travel time along links. Train design optimization seeks to determine the optimal number of trains, their routes, and associated blocks, subject to various capacity and operational constraints at rail links and yards. An iterative heuristic algorithm is proposed to attack the computational burden for real-world networks. The solution algorithm considers the impact of volume on travel time in a congested or near-congested network. The proposed heuristics provide quality solutions with high speed, demonstrated by numerical experiments for small instances. A case study is conducted for the network of a major U.S. Class-I railroad based on publicly available data. The paper provides maps showing the criticality of infrastructure in the study area from the viewpoint of strategic planning.


      PubDate: 2014-11-19T02:49:08Z
       
  • Discomfort in mass transit and its implication for scheduling and pricing
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): André de Palma , Moez Kilani , Stef Proost
      This paper discusses the formulation of crowding in public transport and its implications for pricing, seating capacity and optimal scheduling. An analytical model is used to describe the user equilibrium and the optimal equilibrium for different stylized conditions. For the one OD pair case with identical desired arrival time, we derive the optimal dynamic pricing and optimal share of seats. For the uniformly distributed desired arrival times case, we derive the optimal time table and the optimal pricing. Next we generalize the results to the case of a small network with several stations, stochastic choice and allocation of seats.


      PubDate: 2014-11-15T02:47:35Z
       
  • Call for Papers: Shipping, Port and Maritime Logistics
    • Abstract: Publication date: Available online 11 November 2014
      Source:Transportation Research Part B: Methodological




      PubDate: 2014-11-15T02:47:35Z
       
  • A semi-analytical approach for solving the bottleneck model with general
           user heterogeneity
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Yang Liu , Yu (Marco) Nie , Jonathan Hall
      This paper proposes a novel semi-analytical approach for solving the dynamic user equilibrium (DUE) of a bottleneck model with general heterogeneous users. The proposed approach makes use of the analytical solutions from the bottleneck analysis to create an equivalent assignment problem that admits closed-form commute cost functions. The equivalent problem is a static and asymmetric traffic assignment problem, which can be formulated as a variational inequality problem (VIP). This approach provides a new tool to analyze the properties of the bottleneck model with general heterogeneity, and to design efficient solution methods. In particular, the existence and uniqueness of the DUE solution can be established using the P-property of the Jacobian matrix. Our numerical experiments show that a simple decomposition algorithm is able to quickly solve the equivalent VIP to high precision. The proposed VIP formation is also extended to address simultaneous departure time and route choice in a single O–D origin-destination network with multiple parallel routes.


      PubDate: 2014-11-15T02:47:35Z
       
  • Real-time congestion pricing strategies for toll facilities
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Jorge A. Laval , Hyun W. Cho , Juan C. Muñoz , Yafeng Yin
      This paper analyzes the dynamic traffic assignment problem on a two-alternative network with one alternative subject to a dynamic pricing that responds to real-time arrivals in a system optimal way. Analytical expressions for the assignment, revenue and total delay in each alternative are derived as a function of the pricing strategy. It is found that minimum total system delay can be achieved with many different pricing strategies. This gives flexibility to operators to allocate congestion to either alternative according to their specific objective while maintaining the same minimum total system delay. Given a specific objective, the optimal pricing strategy can be determined by finding a single parameter value in the case of HOT lanes. Maximum revenue is achieved by keeping the toll facility at capacity with no queues for as long as possible. Guidelines for implementation are discussed.


      PubDate: 2014-11-15T02:47:35Z
       
  • Regenerator Location Problem and survivable extensions: A hub covering
           location perspective
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Barış Yıldız , Oya Ekin Karaşan
      In a telecommunications network the reach of an optical signal is the maximum distance it can traverse before its quality degrades. Regenerators are devices to extend the optical reach. The regenerator placement problem seeks to place the minimum number of regenerators in an optical network so as to facilitate the communication of a signal between any node pair. In this study, the Regenerator Location Problem is revisited from the hub location perspective directing our focus to applications arising in transportation settings. Two new dimensions involving the challenges of survivability are introduced to the problem. Under partial survivability, our designs hedge against failures in the regeneration equipment only, whereas under full survivability failures on any of the network nodes are accounted for by the utilization of extra regeneration equipment. All three variations of the problem are studied in a unifying framework involving the introduction of individual flow-based compact formulations as well as cut formulations and the implementation of branch and cut algorithms based on the cut formulations. Extensive computational experiments are conducted in order to evaluate the performance of the proposed solution methodologies and to gain insights from realistic instances.


      PubDate: 2014-11-15T02:47:35Z
       
  • Editorial Board
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69




      PubDate: 2014-10-29T02:46:19Z
       
  • The shared-taxi problem: Formulation and solution methods
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Hadi Hosni , Joe Naoum-Sawaya , Hassan Artail
      With the rising fuel costs, ride sharing is becoming a common mode of transportation. Sharing taxis which has been prominent in several developing countries is also becoming common in several cities around the world. Sharing taxis presents several advantages as it minimizes vacant seats in cars thus reducing costs on taxi operators which results in significantly lower taxi fares for passengers. Besides the economical advantages, taxi sharing is highly important for reducing congestion on the roads and for minimizing the impact of transportation on the environment. In this paper, we formulate the problem of assigning passengers to taxis and computing the optimal routes of taxis as a mixed integer program. To solve the proposed model, we present a Lagrangian decomposition approach which exploits the structure of the problem leading to smaller problems that are solved separately. Furthermore, we propose two heuristics that are used to obtain good quality feasible solutions. The Lagrangian approach along with the heuristics are implemented and compared to solving the full problem using CPLEX. The computational results indicate the efficiency of the methodology in providing tighter bounds than CPLEX in shorter computational time.


      PubDate: 2014-10-29T02:46:19Z
       
  • Stop-and-go traffic analysis: Theoretical properties, environmental
           impacts and oscillation mitigation
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Xiaopeng Li , Jianxun Cui , Shi An , Mohsen Parsafard
      This study aims (i) to analyze theoretical properties of a recently proposed describing-function (DF) based approach (Li and Ouyang, 2011; Li et al., 2012) for traffic oscillation quantification, (ii) to adapt it for estimating fuel consumption and emission from traffic oscillation and (iii) to explore vehicle control strategies of smoothing traffic with advanced technologies. The DF approach was developed to predict traffic oscillation propagation across a platoon of vehicles following each other by a nonlinear car-following law with only the leading vehicle’s input. We first simplify the DF approach and prove a set of properties (e.g., existence and uniqueness of its solution) that assure its prediction is always consistent with observed traffic oscillation patterns. Then we integrate the DF approach with existing estimation models of fuel consumption and emission to analytically predict environmental impacts (i.e., unit-distance fuel consumption and emission) from traffic oscillation. The prediction results by the DF approach are validated with both computer simulation and field measurements. Further, we explore how to utilize advantageous features of emerging sensing, communication and control technologies, such as fast response and information sharing, to smooth traffic oscillation and reduce its environmental impacts. We extend the studied car-following law to incorporate these features and apply the DF approach to demonstrate how these features can help dampen the growth of oscillation and environmental impact measurements. For information sharing, we convert the corresponding extended car-following law into a new fixed point problem and propose a simple bisecting based algorithm to efficiently solve it. Numerical experiments show that these new car-following control strategies can effectively suppress development of oscillation amplitude and consequently mitigate fuel consumption and emission.


      PubDate: 2014-10-29T02:46:19Z
       
  • On the impacts of locally adaptive signal control on urban network
           stability and the Macroscopic Fundamental Diagram
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Vikash V. Gayah , Xueyu (Shirley) Gao , Andrew S. Nagle
      Urban traffic networks are inherently unstable when congested. This instability causes a natural tendency towards spatially inhomogeneous vehicle distributions and less consistent and reproducible relationships between urban traffic variables. It is important to find ways to mitigate this unstable behavior since well-defined relationships between average network flow and density – the MFD – are useful to aid network design and control. This paper examines the impacts of locally adaptive traffic signals – e.g., those that allocate green times proportionally to upstream approach densities – on network stability and the MFD. A family of adaptive signal control strategies is examined on two abstractions of an idealized grid network using an analytical model and an interactive simulation. The results suggest that locally adaptive traffic signals provide stability when the network is moderately congested, which increases average flows and decreases the likelihood of gridlock. These benefits increase with the overall adaptivity of the signals. However, adaptive signals appear to have little to no effect on network stability or the MFD in heavily congested networks as vehicle movement becomes more constrained by downstream congestion and queue spillbacks. Under these conditions, other strategies should be used to mitigate the instability, such as adaptively routing drivers to avoid locally congested regions. These behaviors are verified using more realistic micro-simulations and are consistent with other observations documented in the literature.


      PubDate: 2014-10-24T02:45:52Z
       
  • Online routing and battery reservations for electric vehicles with
           swappable batteries
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Jonathan D. Adler , Pitu B. Mirchandani
      Electric vehicles are becoming a more popular form of transportation, however their limited range has proven problematic. Battery-exchange stations allow the vehicles to swap batteries during their trip, but if a vehicle arrives at a station without a full battery available it may have to wait an extended period of time to get one. The vehicles can be routed so that they avoid stations without available batteries or to keep batteries available for other vehicles that need them in the future. The batteries can also be reserved during the routing process so that each vehicle is ensured the battery it plans to use is available. This paper provides a method of online routing of electric vehicles and making battery reservations that minimizes the average delay of the all vehicles by occasionally detouring them to the benefit of future ones. The system is modeled as a Markov chance-decision process and the optimal policy is approximated using the approximate dynamic programming technique of temporal differencing with linear models. The solution algorithm provides a quick way for vehicles to be routed using onboard vehicle software connected to a central computer. Computational results for the algorithm are provided using data on the Arizona highway network.


      PubDate: 2014-10-24T02:45:52Z
       
  • A parsimonious model for the formation of oscillations in car-following
           models
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Jorge A. Laval , Christopher S. Toth , Yi Zhou
      This paper shows that the formation and propagation of traffic oscillations in the absence of lane changes can be explained by the stochastic nature of drivers’ acceleration processes. By adding a white noise to drivers’ desired acceleration in free-flow, oscillations are produced that accord well with observation. This theory suggests that driver error is a function of roadway geometry, that it determines the average speed at the bottleneck, as well as oscillation period and amplitude. The model has been implemented with a single additional parameter compared to the kinematic wave model with bounded accelerations.


      PubDate: 2014-10-24T02:45:52Z
       
  • Energy minimization in dynamic train scheduling and control for metro rail
           operations
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Xiang Li , Hong K. Lo
      Since the passenger demands change frequently in daily metro rail operations, the headway, cycle time, timetable and speed profile for trains should be adjusted correspondingly to satisfy the passenger demands while minimizing energy consumption. In order to solve this problem, we propose a dynamic train scheduling and control framework. First, we forecast the passenger demand, and determine the headway and cycle time for the next cycle. Then we optimize the reference timetable and speed profile for trains at the next cycle subject to the headway and cycle time constraints. Finally, the automatic train control system is used to operate trains with real-life conditions based on the reference timetable and speed profile. In this paper, we focus on the optimization of the timetable and speed profile. Generally speaking, the former distributes the cycle time to different stations and inter-stations under the headway constraint, and the latter controls the trains’ speeds at inter-stations to reduce the consumption on tractive energy and increase the storage on regenerative energy. In order to achieve a global optimality on energy saving, we formulate an integrated energy-efficient timetable and speed profile optimization model, which is transformed to a convex optimization problem by using the linear approximation method. We use the Kuhn–Tucker conditions to solve the optimal solution and present some numerical experiments based on the actual operation data of Beijing Metro Yizhuang Line of China, which shows that the integrated approach can reduce the net energy consumption around 11% than the practical timetable. Furthermore, with given passenger demand sequence at off-peak hours, the dynamic scheduling and integrated optimization approach with adaptive cycle time can reduce the net energy consumption around 7% than the static scheduling and integrated optimization approach with fixed cycle time.


      PubDate: 2014-10-24T02:45:52Z
       
  • Game-theoretical models for competition analysis in a new emerging liner
           container shipping market
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Hua Wang , Qiang Meng , Xiaoning Zhang
      This paper develops three game-theoretical models to analyze shipping competition between two carriers in a new emerging liner container shipping market. The behavior of each carrier is characterized by an optimization model with the objective to maximize his payoff by setting optimal freight rate and shipping deployment (a combination of service frequency and ship capacity setting). The market share for each carrier is determined by the Logit-based discrete choice model. Three competitive game strategic interactions are further investigated, namely, Nash game, Stackelberg game and deterrence by taking account of the economies of scale of the ship capacity settings. Three corresponding competition models with discrete pure strategy are formulated as the variables in shipment deployment are indivisible and the pricing adjustment is step-wise in practice. A ɛ -approximate equilibrium and related numerical solution algorithm are proposed to analyze the effect of Nash equilibrium. Finally, the developed models are numerically evaluated by a case study. The case study shows that, with increasing container demand in the market, expanding ship capacity setting is preferable due to its low marginal cost. Furthermore, Stackelberg equilibrium is a prevailing strategy in most market situations since it makes players attain more benefits from the accommodating market. Moreover, the deterrence effects largely depend on the deterrence objective. An aggressive deterrence strategy may make potential monopolist suffer large benefit loss and an easing strategy has little deterrence effect.


      PubDate: 2014-10-18T02:43:56Z
       
  • The fleet size and mix pollution-routing problem
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Çağrı Koç , Tolga Bektaş , Ola Jabali , Gilbert Laporte
      This paper introduces the fleet size and mix pollution-routing problem which extends the pollution-routing problem by considering a heterogeneous vehicle fleet. The main objective is to minimize the sum of vehicle fixed costs and routing cost, where the latter can be defined with respect to the cost of fuel and CO2 emissions, and driver cost. Solving this problem poses several methodological challenges. To this end, we have developed a powerful metaheuristic which was successfully applied to a large pool of realistic benchmark instances. Several analyses were conducted to shed light on the trade-offs between various performance indicators, including capacity utilization, fuel and emissions and costs pertaining to vehicle acquisition, fuel consumption and drivers. The analyses also quantify the benefits of using a heterogeneous fleet over a homogeneous one.


      PubDate: 2014-10-18T02:43:56Z
       
  • Approximating dynamic equilibrium conditions with macroscopic fundamental
           diagrams
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Mehmet Yildirimoglu , Nikolas Geroliminis
      Real-time coordinated traffic management strategies that benefit from parsimonious models with aggregated network dynamics, provide a new generation of smart hierarchical strategies to improve network capacity and performance. However, this raises the question of route choice behavior in case of heterogeneous urban networks, where different parts of the city are subject to different types of control. Traffic equilibrium phenomena have not been thoroughly investigated in these models. Approximate traffic equilibrium conditions can be integrated within the parsimonious traffic models to develop regional routing strategies, while detailed route choice strategies can be incorporated at a later stage in a hierarchical framework. In this study, we develop an aggregated and approximate dynamic traffic assignment (DTA) procedure to be incorporated in the macroscopic fundamental diagram (MFD) dynamics, and establish dynamic stochastic user equilibrium (DSUE) conditions. The methodology consists of two main components; stochastic network loading and a fixed-point solution method. Loading procedure is designed to handle stochastic components in the model such as trip length uncertainty, variation of speeds across the links, perception error of travelers. The results taken from this procedure are averaged through the well-known method of successive averages (MSA) to reach fixed-point solution for the system. Real-time route guidance strategies can be revisited towards a “system of systems” approach.


      PubDate: 2014-10-14T02:43:13Z
       
  • On uniqueness and proportionality in multi-class equilibrium assignment
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Michael Florian , Calin D. Morosan
      Over the past few years, much attention has been paid to computing flows for multi-class network equilibrium models that exhibit uniqueness of the class flows and proportionality (Bar-Gera et al., 2012). Several new algorithms have been developed such as bush based methods of Bar-Gera (2002), Dial (2006), and Gentile (2012) that are able to obtain very fine solutions of network equilibrium models. These solutions can be post processed (Bar-Gera, 2006) in order to ensure proportionality and class uniqueness of the flows. Recently developed, the TAPAS, algorithm (Bar Gera, 2010) is able to produce solutions that have proportionality embedded, without requiring post processing. It was generally accepted that these methods for solving UE traffic assignment are the only way to obtain unique path and class link flows. The purpose of this paper is to show that the linear approximation method and some of its variants satisfy these conditions as well. In addition, some analytical results regarding the relation between steps of the linear approximation algorithm and the path flows entropy are presented.
      Graphical abstract image

      PubDate: 2014-10-04T02:38:52Z
       
  • Benders Decomposition for Discrete–Continuous Linear Bilevel
           Problems with application to traffic network design
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Pirmin Fontaine , Stefan Minner
      We propose a new fast solution method for linear Bilevel Problems with binary leader and continuous follower variables under the partial cooperation assumption. We reformulate the Bilevel Problem into a single-level problem by using the Karush–Kuhn–Tucker conditions. This non-linear model can be linearized because of the special structure achieved by the binary leader decision variables and subsequently solved by a Benders Decomposition Algorithm to global optimality. We illustrate the capability of the approach on the Discrete Network Design Problem which adds arcs to an existing road network at the leader stage and anticipates the traffic equilibrium for the follower stage. Because of the non-linear objective functions of this problem, we use a linearization method for increasing, convex and non-linear functions based on continuous variables. Numerical tests show that this algorithm can solve even large instances of Bilevel Problems.


      PubDate: 2014-10-04T02:38:52Z
       
  • A simple procedure for the calculation of the covariances of any
           Generalized Extreme Value model
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Vittorio Marzano
      This paper illustrates a simple procedure for calculating the covariances underlying any Generalized Extreme Value (GEV) model, based on an appropriate generalization of a result already established in the literature for the Cross-Nested Logit model (i.e. a particular GEV model). Specifically, the paper proves that the covariances in any GEV model are always expressed by a one-dimensional integral, whose integrand function is available in closed form as a function of the generating function of the GEV model. This integral may be simulated very easily with a parsimonious computational burden. Two practical examples are also presented. The first is an application to the CNL model, so as to check the consistency of the proposed method with the results already established in the literature. The second deals with the calculation of the covariances of the Network GEV (NGEV) model: notably, the NGEV is the most general type of GEV model available so far, and its covariances have not yet been calculated. On this basis, insights on the domain of the covariances reproduced by the NGEV model are also presented.


      PubDate: 2014-09-29T02:16:10Z
       
  • Single-line rail rapid transit timetabling under dynamic passenger demand
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Eva Barrena , David Canca , Leandro C. Coelho , Gilbert Laporte
      Railway planning is a complex activity which is usually decomposed into several stages, traditionally network design, line design, timetabling, rolling stock, and staffing. In this paper, we study the design and optimization of train timetables for a rail rapid transit (RRT) line adapted to a dynamic demand environment, which focuses on creating convenient timetables for passengers. The objective is to minimize the average passenger waiting time at the stations, thus focusing on passenger welfare. We first propose two mathematical programming formulations which generalize the non-periodic train timetabling problem on a single line under a dynamic demand pattern. We then analyze the properties of the problem before introducing a fast adaptive large neighborhood search (ALNS) metaheuristic in order to solve large instances of the problem within short computation times. The algorithm yields timetables that may not be regular or periodic, but are adjusted to a dynamic demand behavior. Through extensive computational experiments on artificial and real-world based instances, we demonstrate the computational superiority of our ALNS compared with a truncated branch-and-cut algorithm. The average reduction in passenger waiting times is 26%, while the computational time of our metaheuristic is less than 1% of that required by the alternative CPLEX-based algorithm. Out of 120 open instances, we obtain 84 new best known solutions and we reach the optimum on 10 out of 14 instances with known optimal solutions.


      PubDate: 2014-09-29T02:16:10Z
       
  • Price of anarchy for non-atomic congestion games with stochastic demands
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Chenlan Wang , Xuan Vinh Doan , Bo Chen
      We generalize the notions of user equilibrium, system optimum and price of anarchy to non-atomic congestion games with stochastic demands. In this generalized model, we extend the two bounding methods from Roughgarden and Tardos (2004) and Correa et al. (2008) to bound the price of anarchy, and compare the upper bounds we have obtained. Our results show that the price of anarchy depends not only on the class of cost functions but also demand distributions and, to some extent, the network topology. The upper bounds are tight in some special cases, including the case of deterministic demands.


      PubDate: 2014-09-23T01:29:01Z
       
  • A variational formulation for higher order macroscopic traffic flow
           models: Numerical investigation
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Guillaume Costeseque , Jean-Patrick Lebacque
      This paper deals with numerical methods providing semi-analytic solutions to a wide class of macroscopic traffic flow models for piecewise affine initial and boundary conditions. In a very recent paper, a variational principle has been proved for models of the Generic Second Order Modeling (GSOM) family, yielding an adequate framework for effective numerical methods. Any model of the GSOM family can be recast into its Lagrangian form as a Hamilton–Jacobi equation (HJ) for which the solution is interpreted as the position of vehicles. This solution can be computed thanks to Lax–Hopf like formulas and a generalization of the inf-morphism property. The efficiency of this computational method is illustrated through a numerical example and finally a discussion about future developments is provided.


      PubDate: 2014-09-23T01:29:01Z
       
  • Fare evasion in proof-of-payment transit systems: Deriving the optimum
           inspection level
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Benedetto Barabino , Sara Salis , Bruno Useli
      In proof-of-payment systems, fare evasion represents a crucial topic for public transport companies (PTCs) due to lost fare revenues, damaged corporate image, and increased levels of violence on public transport, which might also have negative economic repercussions on PTCs. Therefore, there is a need to establish the level of inspection (i.e. the number of inspectors) to tackle fare dodgers as a possible option. By building on previous models, this paper develops a formal economic framework to derive the optimum inspection level in a long time window, based on system-wide profit maximization when fare evasion exists. The framework takes into account: (i) the refined segmentation of passengers and potential fare evaders, (ii) the variability of perceived inspection level by passengers, and (iii) the fact that an inspector cannot fine every passenger caught evading. Its implementation is illustrated by using three years of real data from an Italian PTC. Based on 27,514 stop-level inspections and 10,586 on-board personal interviews, the results show that the optimum inspection level is 3.8%. Put differently, it is sufficient to check 38 passengers out of every 1000 to maximize profit in the presence of fare evasion. This outcome is very useful, because it improves the one obtained in previous formulations. Indeed, profit maximization is achieved with a lower number of inspectors, thus reducing inspection costs, which are relevant determinants in proficient PTCs. Finally, the framework is flexible and may be applied to public transport modes other than buses as long as proof-of-payment systems are in use.


      PubDate: 2014-09-19T01:04:44Z
       
  • Assessing partial observability in network sensor location problems
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Francesco Viti , Marco Rinaldi , Francesco Corman , Chris M.J. Tampère
      The quality of information on a network is crucial for different transportation planning and management applications. Problems focusing on where to strategically extract this information can be broadly subdivided into observability problems, which rely on the topological properties of the network, and flow-estimation problems, where (prior) information on observed flows is needed to identify optimal sensor locations. This paper contributes mainly to the first category: more specifically, it presents a new methodology and an intuitive metric able to quantify the quality of a solution in case of partial observability, i.e. when not all flow variables are observed or can be uniquely determined from the observed flows. This methodology is based on existing approaches that can efficiently find solutions for full observability (i.e., the set of sensors needed to make the system fully determined), and exploits only the algebraic relations between link, route and origin–destination flow variables to quantify the information contained in any arbitrary subset of these variables. The new metric allows, through its adoption within simple search algorithms, to efficiently select sensor locations when the number of available sensors is limited by, for example, budget constraints and is less than the number needed to guarantee full observability. The chosen positions aim at selecting those locations that contain the largest information content on the whole network. This is an important contribution in this field, since even in small sized networks the solution for full observability requires an exceedingly large amount of sensors. The assessment of partial observability solutions, based on explicit route enumeration, allows one to categorize families of full observability solutions, and shows that these contain different information potential. This way, it is possible to rank solutions requiring a lower number of sensors while containing the same information content. We tested this new methodology both on toy networks, in order to analyse the properties of the metric and illustrate its logic, and to explain and test heuristic search algorithms for optimal sensor positioning on a real-sized network. Analysis of partial observability solutions shows that the basic search algorithms succeed in finding the links that contain the largest deal of information in a network.


      PubDate: 2014-09-19T01:04:44Z
       
  • Travel time resilience of roadway networks under disaster
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Reza Faturechi , Elise Miller-Hooks
      A bi-level, three-stage Stochastic Mathematical Program with Equilibrium Constraints (SMPEC) is proposed for quantifying and optimizing travel time resilience in roadway networks under non-recurring natural or human-induced disaster events. At the upper-level, a sequence of optimal preparedness and response decisions is taken over pre-event mitigation and preparedness and post-event response stages of the disaster management life cycle. Assuming semi-adaptive user behavior exists shortly after the disaster and after the implementation of immediate response actions, the lower-level problem is formulated as a Partial User Equilibrium, where only affected users are likely to rethink their routing decisions. An exact Progressive Hedging Algorithm is presented for solution of a single-level equivalent, linear approximation of the SMPEC. A recently proposed technique from the literature that uses Schur’s decomposition with SOS1 variables in creating a linear equivalent to complementarity constraints is employed. Similarly, recent advances in piecewise linearization are exploited in addressing nonseparable link travel time functions. The formulation and solution methodology are demonstrated on an illustrative example.


      PubDate: 2014-09-19T01:04:44Z
       
  • An integrated approach for timetabling and vehicle scheduling problems to
           analyze the trade-off between level of service and operating costs of
           transit networks
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): Omar J. Ibarra-Rojas , Ricardo Giesen , Yasmin A. Rios-Solis
      In transit systems there is a critical trade-off between the level of service and operating costs. At the planning level, for a given network design, this trade-off is captured by the timetabling (TT) and vehicle scheduling (VS) problems. In the TT problem we try to maximize the number of passengers benefited by well timed transfers, while in the VS problem we seek to minimize the operating costs, which are related to the fleet size. This paper presents two integer linear programming models for the TT and VS problems, and combines them in a bi-objective integrated model. We propose and implement an ∊-constraint method to jointly solve this TT and VS bi-objective problem. This allows to analyze the trade-off between these two criteria in terms of Pareto fronts. Numerical experiments show that our proposed approach can solve scenarios with up to 50 bus lines.
      Graphical abstract image

      PubDate: 2014-09-19T01:04:44Z
       
  • Understanding relative efficiency among airports: A general dynamic model
           for distinguishing technical and allocative efficiency
    • Abstract: Publication date: December 2014
      Source:Transportation Research Part B: Methodological, Volume 70
      Author(s): A. George Assaf , David Gillen , Efthymios G. Tsionas
      The paper introduces a new dynamic frontier model that is used to analyze the impact of both ownership and regulation on airport technical and allocative efficiencies. We differentiate between the short and long-term effects. Based on a large sample of international airports, we find in the short-run the majority of the improvements are from reducing technical inefficiency, which come for the most part from adjusting output, something that can be accomplished in the short-term. There are relatively small changes, in the short run, resulting from improving allocative efficiency. We find that adding economic regulation leads to a decrease in technical efficiency in the short-run. Quite different conclusions hold for the long-term; there are improvements available from reducing allocative inefficiency and comparable benefits are available from cutting technical inefficiency. In the long-run we find that technical and allocative inefficiency decreases by moving away from government owned to fully privatized airports and moving away from rigid regulation.


      PubDate: 2014-09-19T01:04:44Z
       
  • An analysis of logit and weibit route choices in stochastic assignment
           paradox
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Jia Yao , Anthony Chen
      Paradox in the transportation literature is about improving an existing link or adding a new link can actually increase network-wide travel costs or travel costs of each traveler. In this paper, we investigate the stochastic assignment paradox using the multinomial weibit (MNW) model, a new route choice model developed by Castillo et al. (2008), and compare it to the counter-intuitive results of the multinomial logit (MNL) model when an inferior travel alternative is marginally improved. Using a simple two-link network, we derive the conditions for paradoxical phenomenon to occur for both route choice models, and graphically compare and contrast the paradoxical regions. The results show the stochastic assignment paradox depends on how the cost difference is being considered in the route choice model (i.e., absolute cost difference in the MNL model and relative cost difference in the MNW model) to some extent. Hence, the stochastic paradox analysis is extended to a hybrid model that considers both MNW and MNL models (i.e., both relative cost difference and absolute cost difference). The paradox area of the hybrid model is shown to be a combination of the paradox areas of the two models. In addition, the stochastic assignment paradox conditions derived for a simple two-link network are generalized to three cases: (a) one O–D pair with multiple links on a route, (b) multiple O–D pairs, and (c) adding a new link. Analytical solutions, graphical illustrations, and numerical results are provided to demonstrate the stochastic paradox under different conditions. Future research directions are also discussed in the paper.


      PubDate: 2014-09-02T23:11:05Z
       
  • Real time traffic states estimation on arterials based on trajectory data
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Gabriel Hiribarren , Juan Carlos Herrera
      New technologies able to register vehicle trajectories, such as GPS (Global Position Systems)-enabled cell phones, have opened a new way of collecting traffic data. However, good methods that convert these data into useful information are needed to leverage these data. In this study a new method to estimate traffic states on arterials based on trajectory data is presented and assessed. The method is based on the Lighthill–Whitham–Richards (LWR) theory. By using this theory, traffic dynamics on arterials can be better captured by extracting more information from the same piece of data. Trajectory data used consist of the trajectory of the latest equipped vehicle that crossed the segment under study. Preliminary analysis based on micro-simulation suggests that this method yields good traffic state estimates both at congested and uncongested situations, even for very low penetration rates (1%). The method is also able to forecast queue length at intersections and travel times along a road section.


      PubDate: 2014-09-02T23:11:05Z
       
  • A three level location-inventory problem with correlated demand
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Mehrdad Shahabi , Avinash Unnikrishnan , Ehsan Jafari-Shirazi , Stephen D. Boyles
      This paper considers a three level location-inventory problem where demand across the retailers is assumed to be correlated. We first present a reformulation scheme by which the initial formulation is transformed into a mixed integer conic quadratic program. In addition, we propose a solution approach based on an outer approximation strategy and show the algorithmic advantage of such framework for this class of programs. The results from numerical experiments show that the proposed solution procedure clearly outperforms state-of-the-art commercial solvers. In addition, we show that neglecting the effect of correlation can lead to substantially sub-optimal solutions.


      PubDate: 2014-09-02T23:11:05Z
       
 
 
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