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  Subjects -> TRANSPORTATION (Total: 132 journals)
    - AIR TRANSPORT (5 journals)
    - AUTOMOBILES (19 journals)
    - RAILROADS (4 journals)
    - ROADS AND TRAFFIC (4 journals)
    - SHIPS AND SHIPPING (15 journals)
    - TRANSPORTATION (85 journals)

TRANSPORTATION (85 journals)

Accident Analysis & Prevention     Partially Free   (Followers: 16)
AI & Society     Hybrid Journal   (Followers: 2)
Archives of Transport     Open Access   (Followers: 4)
Bitácora Urbano-Territorial     Open Access   (Followers: 1)
Cities in the 21st Century     Open Access   (Followers: 9)
Economics of Transportation     Partially Free   (Followers: 11)
EURO Journal of Transportation and Logistics     Hybrid Journal   (Followers: 4)
European Transport Research Review     Open Access   (Followers: 9)
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: 3)
IET Intelligent Transport Systems     Hybrid Journal   (Followers: 3)
International Innovation – Transport     Open Access  
International Journal of Applied Logistics     Full-text available via subscription   (Followers: 4)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 5)
International Journal of Critical Infrastructure Protection     Hybrid Journal   (Followers: 5)
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 3)
International Journal of Electronic Transport     Hybrid Journal   (Followers: 2)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 5)
International Journal of Intelligent Transportation Systems Research     Hybrid Journal   (Followers: 5)
International Journal of Micro-Nano Scale Transport     Full-text available via subscription   (Followers: 1)
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: 5)
International Journal of Services Technology and Management     Hybrid Journal  
International Journal of Sustainable Transportation     Hybrid Journal   (Followers: 6)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 11)
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: 1)
Journal of Advanced Transportation     Hybrid Journal   (Followers: 9)
Journal of Modern Transportation     Full-text available via subscription  
Journal of Navigation     Hybrid Journal   (Followers: 18)
Journal of Sport & Social Issues     Hybrid Journal   (Followers: 7)
Journal of the Transportation Research Forum     Open Access   (Followers: 3)
Journal of Transport and Land Use     Open Access   (Followers: 8)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 5)
Journal of Transport Geography     Hybrid Journal   (Followers: 12)
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: 6)
Journal of Transportation Security     Hybrid Journal   (Followers: 2)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 11)
Journal of Transportation Technologies     Open Access   (Followers: 7)
Journal of Waterway Port Coastal and Ocean Engineering     Full-text available via subscription   (Followers: 5)
Les Dossiers du Grihl     Open Access  
Logistique & Management     Full-text available via subscription  
Mechatronics, Electrical Power, and Vehicular Technology     Open Access  
Modern Transportation     Open Access   (Followers: 1)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
Open Journal of Safety Science and Technology     Open Access   (Followers: 2)
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: 18)
Public Transport     Hybrid Journal   (Followers: 9)
Recherche Transports Sécurité     Hybrid Journal   (Followers: 1)
Research in Transportation Business and Management     Partially Free   (Followers: 3)
Revista Transporte y Territorio     Open Access   (Followers: 1)
SourceOCDE Transports     Full-text available via subscription   (Followers: 1)
Sport, Education and Society     Hybrid Journal   (Followers: 10)
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: 5)
Transport and Telecommunication Journal     Open Access   (Followers: 2)
Transport in Porous Media     Hybrid Journal  
Transport Reviews: A Transnational Transdisciplinary Journal     Hybrid Journal   (Followers: 4)
Transportation     Hybrid Journal   (Followers: 12)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 3)
Transportation Journal     Full-text available via subscription   (Followers: 3)
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 20)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 19)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 11)
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 26)
Transportation Science     Full-text available via subscription   (Followers: 14)
TRANSPORTES     Open Access   (Followers: 1)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 1)
Transportmetrica B : Transport Dynamics     Hybrid Journal  
Travel Medicine and Infectious Disease     Hybrid Journal   (Followers: 2)
Urban, Planning and Transport Research     Open Access   (Followers: 1)
World Review of Intermodal Transportation Research     Hybrid Journal   (Followers: 4)
Транспортні системи та технології перевезень     Open Access  
Journal Cover Transportation Research Part B: Methodological
   [21 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0191-2615
     Published by Elsevier Homepage  [2563 journals]   [SJR: 3.08]   [H-I: 60]
  • Finding anonymous tolls to realize target flow pattern in networks with
           continuously distributed value of time
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65
      Author(s): Wen-Xiang Wu , Hai-Jun Huang
      Considering user heterogeneity in terms of a continuously distributed value of time, we investigate, on the base of so-called Wardrop’s third principle, the time-versus-cost network equilibrium and system optimum problem with fixed demand. To realize a target flow pattern through imposing anonymous path tolls, we propose a time difference-based pricing in which every user is charged a toll computed from the time difference between adjacent paths ordered in the decreasing order of travel times. We find that, whenever travel disutility is measured in cost or time units, the anonymous marginal cost pricing does not exist. We further show that, if and only if the coefficient matrix of a linear system corresponding to the derived optimal path toll pattern and its augmented matrix have the same rank, an anonymous link toll pattern exists.


      PubDate: 2014-07-24T19:15:19Z
       
  • Efficient auctions for distributed transportation procurement
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65
      Author(s): Su Xiu Xu , George Q. Huang
      The purpose of this paper is to propose allocatively efficient auction mechanisms for the distributed transportation procurement problem (DTPP), which is generally the problem of matching demands and supplies over a transportation network. We first construct a one-sided Vickrey–Clarke–Groves (O-VCG) combinatorial auction for the DTPP where carriers are allowed to bid on bundles of lanes. The O-VCG auction minimizes the total transportation cost (i.e., allocative efficiency) and induces truthful bidding from carriers (i.e., incentive compatibility). To simplify the execution of auction, we next propose a primal–dual Vickrey (PDV) auction based on insights from the known Ausubel auctions and the primal–dual algorithm. The PDV auction is actually a multi-round descending auction that seems simple enough for bidders. The PDV auction realizes VCG payments and truthful bidding under the condition of seller-submodularity, which implies that the effect of each individual carrier is decreasing when the coalition increases. Such is the case for the DTPP in an oversupplied transportation market. The winner determination problem of O-VCG auction is solved by the proposed primal–dual algorithm when seller-submodularity holds. Finally, carriers may reveal less private information in the PDV auction due to its dynamic procedures.


      PubDate: 2014-07-24T19:15:19Z
       
  • Transportation and economies of scale in recycling low-value materials
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65
      Author(s): Jiuh-Biing Sheu , Yenming J. Chen
      This study investigates the economic incentive-drivers used in various configurations in green supply chains. The configurations of competitive suppliers and integrated transportation are studied for recycled materials with low economic value but high environmental impact. Arguments are embodied in a competitive game that manifests interactions among competing manufacturers, suppliers of virgin materials, suppliers of recycled materials, and the government. Because of market size and technology limitation, long hauling to few remote treatment facilities is observed in practice. Demand-dependent transportation efficiency arisen from economies of scale thus affects the equilibrium states in the game of this recycling system. Managerial insights are provided to encourage the use of low-value recycled materials. A tax-subsidy system is conditionally effective when using recycled materials maintains quality. When quality becomes compromised by mixing recycled materials, we find that integrating suppliers of recycled materials with those of virgin materials can make the tax-subsidy system effective again.


      PubDate: 2014-07-24T19:15:19Z
       
  • Editorial Board
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65




      PubDate: 2014-07-24T19:15:19Z
       
  • Airport congestion pricing when airlines price discriminate
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65
      Author(s): Achim I. Czerny , Anming Zhang
      This paper extends the literature on airport congestion pricing by allowing carriers to price-discriminate between the business and leisure passengers when operating costs are the same for all passengers. The main results are: First, the second-best discriminating business fare exceeds the first-best uniform fare (which equals the external part of the marginal congestion costs), while the second-best discriminating leisure fare is lower than the first-best uniform fare. Second, the optimal airport charge implements the first-best uniform or second-best discriminating fares. Importantly, this charge can always be higher than what would be expected when all passengers were treated as having the same time valuation. This result provides some support to the finding that the welfare losses associated with an atomistic airport congestion charge may be low.


      PubDate: 2014-07-24T19:15:19Z
       
  • Finding most reliable paths on networks with correlated and shifted
           log–normal travel times
    • Abstract: Publication date: August 2014
      Source:Transportation Research Part B: Methodological, Volume 66
      Author(s): Karthik K. Srinivasan , A.A. Prakash , Ravi Seshadri
      There is a growing interest in modeling travel time uncertainty in transportation networks in addition to optimizing the reliability of travel times at the path and network level. This paper focuses on the analysis and optimization of travel time (including stopped delays) Reliability on the Urban Road Network in Chennai. Specifically, two objectives are investigated. The first objective involves the quantification of travel time reliability at the link and path level. In particular, the distribution of link travel times is quantified for the Chennai Urban road network using empirical data. The results indicate that the shifted log–normal distribution (SLN) reasonably represents link travel time for all facility types and relevant facility wise distribution parameters are estimated. Further, the resulting path travel time distribution is approximated by a SLN distribution, which is computationally less expensive than traditional Monte-Carlo estimation techniques with an acceptable compromise on accuracy. The second objective addresses the optimal reliability path problem on a network with SLN link travel times with general correlation structure. For this problem, it is shown that the sub-path optimality property of shortest path problems does not hold making traditional label-setting/label correcting algorithms inapplicable. Consequently, a sufficient optimality condition based on reliability bounds is established and a new network optimization algorithm is proposed and proof of correctness is presented. The convergence rate of the algorithm was shown to increase at every iteration under some mild conditions. The computational performance of the proposed algorithm is investigated using synthetic and real-world networks and found to be reasonably accurate.


      PubDate: 2014-07-24T19:15:19Z
       
  • Consistent formulation of network equilibrium with stochastic flows
    • Abstract: Publication date: August 2014
      Source:Transportation Research Part B: Methodological, Volume 66
      Author(s): Shoichiro Nakayama , David Watling
      Traffic flows in real-life transportation systems vary on a daily basis. According to traffic flow theory, such variability should induce a similar variability in travel times, but this “internal consistency” is generally not captured by existing network equilibrium models. We present an internally-consistent network equilibrium approach, which considers two potential sources of flow variability: (i) daily variation in route choice and (ii) daily variation in origin–destination demand. We particularly aspire to a flexible formulation that permits alternative statistical assumptions, which allows the best fit to be made to observed variability data in particular applications. Joint probability distributions of route—and therefore link—flows are derived under several assumptions concerning stochastic driver behavior. A stochastic network equilibrium model with stochastic demands and route choices is formulated as a fixed point problem. We explore limiting cases which allow an equivalent convex optimization problem to be defined, and finally apply this method to a real-life network of Kanazawa City, Japan.


      PubDate: 2014-07-24T19:15:19Z
       
  • Modeling distribution tail in network performance assessment: A
           mean-excess total travel time risk measure and analytical estimation
           method
    • Abstract: Publication date: August 2014
      Source:Transportation Research Part B: Methodological, Volume 66
      Author(s): Xiangdong Xu , Anthony Chen , Lin Cheng , Hong K. Lo
      Risk measures are often used by decision makers (DMs) as a scalar risk characterization by integrating the statistical characteristics of risk as well as the DMs’ risk strategy towards uncertainty. A good risk measure typically needs to have a risk preference control mechanism, a complete uncertainty characterization, and a practical implementation strategy. Total travel time reliability (TTTR) and total travel time budget (TTTB) are two risk measures recently proposed for assessing transportation network performance under uncertainty. In this paper, we propose the mean-excess total travel time (METTT) as an alternative network-wide risk measure to more cost-effectively capture the distribution tail, and develop an analytical method to estimate risk measures without knowing the explicit distribution form of TTT uncertainty. Methodologically, the METTT measure characterizes the distribution tail of exceeding the TTTB via the conditional expectation without requiring an extraordinary reliability level. It is able to account for the tradeoff between planners’ risk-aversion attitude and the unacceptable risk, which avoids the need of setting a too conservative reliability requirement in the TTTB to reduce the unacceptable risk. The explicit distribution tail consideration in the METTT could lower the construction cost and substantially reduce the unacceptable risk of network capacity enhancement under uncertainty. To enhance the practicality of METTT, we develop an analytical estimation method to efficiently calculate the METTT by using the first four TTT moments as well as the planners’ risk attitude. The TTTR and TTTB measures can also be analytically estimated as a byproduct of the proposed method for assessing the METTT. The analytical feature of the proposed method avoids the burdensome computation of simulation method and also circumvents the need of fitting the explicit TTT distribution form. Numerical results indicate that the proposed method has a desirable and comparable estimation quality in comparison with the theoretical derivation and curve fitting methods.


      PubDate: 2014-07-24T19:15:19Z
       
  • A bi-objective user equilibrium model of travel time reliability in a road
           network
    • Abstract: Publication date: August 2014
      Source:Transportation Research Part B: Methodological, Volume 66
      Author(s): Judith Y.T. Wang , Matthias Ehrgott , Anthony Chen
      Travel time, travel time reliability and monetary cost have been empirically identified as the most important criteria influencing route choice behaviour. We concentrate on travel time and travel time reliability and review two prominent user equilibrium models incorporating these two factors. We discuss some shortcomings of these models and propose alternative bi-objective user equilibrium models that overcome the shortcomings. Finally, based on the observation that both models use standard deviation of travel time within their measure of travel time reliability, we propose a general travel time reliability bi-objective user equilibrium model. We prove that this model encompasses those discussed previously and hence forms a general framework for the study of reliability related user equilibrium. We demonstrate and validate our concepts on a small three-link example.


      PubDate: 2014-07-24T19:15:19Z
       
  • A Granular Variable Tabu Neighborhood Search for the capacitated
           location-routing problem
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): John Willmer Escobar , Rodrigo Linfati , Maria G. Baldoquin , Paolo Toth
      This paper proposes a new heuristic algorithm for the Capacitated Location-Routing Problem (CLRP), called Granular Variable Tabu Neighborhood Search (GVTNS). This heuristic includes a Granular Tabu Search within a Variable Neighborhood Search algorithm. The proposed algorithm is experimentally compared on the benchmark instances from the literature with several of the most effective heuristics proposed for the solution of the CLRP, by taking into account the CPU time and the quality of the solutions obtained. The computational results show that GVTNS is able to obtain good average solutions in short CPU times, and to improve five best known solutions from the literature. The main contribution of this paper is to show a successful new heuristic for the CLRP, combining two known heuristic approaches to improve the global performance of the proposed algorithm for what concerns both the quality of the solutions and the computing times required to find them.


      PubDate: 2014-07-24T19:15:19Z
       
  • Editorial Board
    • Abstract: Publication date: August 2014
      Source:Transportation Research Part B: Methodological, Volume 66




      PubDate: 2014-07-24T19:15:19Z
       
  • Advances in equilibrium models for analyzing transportation network
           reliability
    • Abstract: Publication date: August 2014
      Source:Transportation Research Part B: Methodological, Volume 66
      Author(s): William H.K. Lam , Hong K. Lo , S.C. Wong



      PubDate: 2014-07-24T19:15:19Z
       
  • Airline route structure competition and network policy
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Hugo E. Silva , Erik T. Verhoef , Vincent A.C. van den Berg
      We analyze the behavior of airlines in terms of route structure choice using a differentiated duopoly model that accounts for congestion externalities, passenger benefits from increased frequency, passenger connecting costs and airline endogenous hub location. We also examine the route structure configuration that maximizes welfare and whether it can arise as an equilibrium when a regulator implements optimal airport pricing, but does not regulate directly the route structure choice. We find that this is not always the case and that, therefore, an instrument directly aimed at regulating route structure choice may be needed to maximize welfare, in addition to per-passenger and per-flight tolls designed to correct output inefficiencies. This holds true when the regulator is constrained to set non-negative tolls, but also for unconstrained tolling. Finally, we also study the relative efficiency of airport pricing when the optimal route structure configuration cannot be decentralized by tolling.


      PubDate: 2014-07-24T19:15:19Z
       
  • Network equilibrium models with battery electric vehicles
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Fang He , Yafeng Yin , Siriphong Lawphongpanich
      The limited driving ranges, the scarcity of recharging stations and potentially long battery recharging or swapping time inevitably affect route choices of drivers of battery electric vehicles (BEVs). When traveling between their origins and destinations, this paper assumes that BEV drivers select routes and decide battery recharging plans to minimize their trip times or costs while making sure to complete their trips without running out of charge. With different considerations of flow dependency of energy consumption of BEVs and recharging time, three mathematical models are formulated to describe the resulting network equilibrium flow distributions on regional or metropolitan road networks. Solution algorithms are proposed to solve these models efficiently. Numerical examples are presented to demonstrate the models and solution algorithms.


      PubDate: 2014-07-24T19:15:19Z
       
  • A method for designing centralized emergency supply network to respond to
           large-scale natural disasters
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Jiuh-Biing Sheu , Cheng Pan
      This paper proposes a method for designing a seamless centralized emergency supply network by integrating three sub-networks (shelter network, medical network, and distribution network) to support emergency logistics operations in response to large-scale natural disasters. The proposed method primarily involves three stage multi-objective (travel distance minimization, operational cost minimization, and psychological cost minimization), mixed-integer linear programming models. The three sub-networks are designed using the proposed programming models. The distinctive features of the proposed method are as follows. (1) The proposed method is demand-driven. The order of the designed sub-networks is shelter, medical, and distribution, with the connections of the latter networks based on the arrangements for the former. (2) The objective functions of three stage programming models include not only traditional objectives such as minimizing total travel distance and operational cost, which supply-side members focus on, but also minimizing the psychological cost experienced by demand-side members. Model tests are conducted to demonstrate that the superiority of a centralized emergency supply network designed by the proposed method over a decentralized one, especially with regard to distribution network design.


      PubDate: 2014-07-24T19:15:19Z
       
  • The optimal design and cost implications of electric vehicle taxi systems
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Nakul Sathaye
      In recent years, taxis in multiple cities and metropolitan areas around the world have shifted to utilizing alternative fuel options. Such change has significant potential to reduce environmental externalities and can contribute to alleviating energy policy concerns. However, little work has been conducted to assess the tradeoffs between selecting various fuels for taxis, or to design alternative fuel taxi systems. These tradeoffs exist as a result of the differing costs associated with fleet replacement, infrastructure deployment, operations and maintenance decisions, and costs to users. This paper aims to address this issue by providing an optimization framework for the design of electric taxi systems, and an assessment of optimal costs associated with various options. We focus on comparing the costs of taxi systems made up of gasoline vehicles, hybrid-electric vehicles, plug-in hybrid electric vehicles with AC Level 2 infrastructure, electric vehicles with battery switching infrastructure, and electric vehicles with DC Level 2 fast charging infrastructure. This approach is based on transit systems design methods and focuses on developing an approximate analytic model for electric taxi systems, which can be expanded upon in future research, to address large-scale taxi systems design problems. Scenario results are presented for various city types.


      PubDate: 2014-07-24T19:15:19Z
       
  • Transit route and frequency design: Bi-level modeling and hybrid
           artificial bee colony algorithm approach
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): W.Y. Szeto , Y. Jiang
      This paper proposes a bi-level transit network design problem where the transit routes and frequency settings are determined simultaneously. The upper-level problem is formulated as a mixed integer non-linear program with the objective of minimizing the number of passenger transfers, and the lower-level problem is the transit assignment problem with capacity constraints. A hybrid artificial bee colony (ABC) algorithm is developed to solve the bi-level problem. This algorithm relies on the ABC algorithm to design route structures and a proposed descent direction search method to determine an optimal frequency setting for a given route structure. The descent direction search method is developed by analyzing the optimality conditions of the lower-level problem and using the relationship between the lower- and upper-level objective functions. The step size for updating the frequency setting is determined by solving a linear integer program. To efficiently repair route structures, a node insertion and deletion strategy is proposed based on the average passenger demand for the direct services concerned. To increase the computation speed, a lower bound of the objective value for each route design solution is derived and used in the fitness evaluation of the proposed algorithm. Various experiments are set up to demonstrate the performance of our proposed algorithm and the properties of the problem.


      PubDate: 2014-07-24T19:15:19Z
       
  • Simultaneous train rerouting and rescheduling on an N-track network: A
           model reformulation with network-based cumulative flow variables
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Lingyun Meng , Xuesong Zhou
      Train dispatching is critical for the punctuality and reliability of rail operations, especially for a complex rail network. This paper develops an innovative integer programming model for the problem of train dispatching on an N-track network by means of simultaneously rerouting and rescheduling trains. Based on a time–space network modeling framework, we first adapt a commonly used big-M method to represent complex “if-then” conditions for train safety headways in a multi-track context. The track occupancy consideration on typical single and double tracks is then reformulated using a vector of cumulative flow variables. This new reformulation technique can provide an efficient decomposition mechanism through modeling track capacities as side constraints which are further dualized through a proposed Lagrangian relaxation solution framework. We further decompose the original complex rerouting and rescheduling problem into a sequence of single train optimization subproblems. For each subproblem, a standard label correcting algorithm is embedded for finding the time dependent least cost path on a time–space network. The resulting dual solutions can be transformed to feasible solutions through priority rules. We present a set of numerical experiments to demonstrate the system-wide performance benefits of simultaneous train rerouting and rescheduling, compared to commonly-used sequential train rerouting and rescheduling approaches.
      Graphical abstract image

      PubDate: 2014-07-24T19:15:19Z
       
  • Exact and meta-heuristic approach for a general heterogeneous dial-a-ride
           problem with multiple depots
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Kris Braekers , An Caris , Gerrit K. Janssens
      Dial-a-ride problems are concerned with the design of efficient vehicle routes for transporting individual persons from specific origin to specific destination locations. In real-life this operational planning problem is often complicated by several factors. Users may have special requirements (e.g. to be transported in a wheelchair) while service providers operate a heterogeneous fleet of vehicles from multiple depots in their service area. In this paper, a general dial-a-ride problem in which these three real-life aspects may simultaneously be taken into account is introduced: the Multi-Depot Heterogeneous Dial-A-Ride Problem (MD-H-DARP). Both a three- and two-index formulation are discussed. A branch-and-cut algorithm for the standard dial-a-ride problem is adapted to exactly solve small problem instances of the MD-H-DARP. To be able to solve larger problem instances, a new deterministic annealing meta-heuristic is proposed. Extensive numerical experiments are presented on different sets of benchmark instances for the homogeneous and the heterogeneous single depot dial-a-ride problem. Instances for the MD-H-DARP are introduced as well. The branch-and-cut algorithm provides considerably better results than an existing algorithm which uses a less compact formulation. All seven previously unsolved benchmark instances for the heterogeneous dial-a-ride problem could be solved to optimality within a matter of seconds. While computation times of the exact algorithm increase drastically with problem size, the proposed meta-heuristic algorithm provides near-optimal solutions within limited computation time for all instances. Several best known solutions for unsolved instances are improved and the algorithm clearly outperforms current state-of-the-art heuristics for the homogeneous and heterogeneous dial-a-ride problem, both in terms of solution quality and computation time.


      PubDate: 2014-07-24T19:15:19Z
       
  • Pre-trip information and route-choice decisions with stochastic travel
           conditions: Theory
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Robin Lindsey , Terry Daniel , Eyran Gisches , Amnon Rapoport
      This paper studies the effects of pre-trip information on route-choice decisions when travel conditions are congested and stochastic. We adopt a model based on the classical two-route network in which free-flow travel times and/or capacities on each route vary unpredictably due to such shocks as bad weather, accidents, and special events. We show that the benefits of information depend on differences between routes in free-flow costs, the shape of the travel cost functions, the severity of congestion and capacity shocks, and the degree of correlation between routes in travel conditions. Information is more likely to be welfare-reducing when free-flow travel costs differ appreciably, travel cost functions are convex, shocks are similar in size on the routes, and route conditions are strongly and positively correlated.


      PubDate: 2014-07-24T19:15:19Z
       
  • Optimal occupancy-driven parking pricing under demand uncertainties and
           traveler heterogeneity: A stochastic control approach
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Zhen (Sean) Qian , Ram Rajagopal
      A novel parking pricing strategy dependent on real-time sensing is proposed to manage the parking demand. Parking pricing and information provision jointly serve as a dynamic stabilized controller to minimize the total travel time (TTT) of the system. Parking prices are adjusted in real time according to the real-time occupancy collected by parking sensors. All the parking information along with parking prices, is then provided for travelers to make real-time parking choices. We model the optimal parking pricing in the preferred (closer) parking cluster as a stochastic control problem. We take into account two types of randomness, demand uncertainties and user heterogeneity in Value of Time (VOT), both of which can be learned by taking real-time measurements. The optimal parking pricing policies are solved using the dynamic programming approach. There exists a critical occupancy for each time period, and the parking prices should be set effective (by diverting travelers to the farther parking lot) when the up-to-date occupancy is above the critical occupancy. From the numerical experiments, we find that the optimal parking policies based on stochastic control models are promising. They can deal with different demand levels (high, low or unstable) and generally outperform the deterministic pricing schemes. It can approach the minimum TTT in most of the cases as if we know the traffic demand in advance of the commuting time. Providing real-time occupancy information alone without setting proper parking prices, seems useful, but marginal, in reducing the parking congestion.


      PubDate: 2014-07-24T19:15:19Z
       
  • The analysis of vehicle crash injury-severity data: A Markov switching
           approach with road-segment heterogeneity
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Yingge Xiong , Justin L. Tobias , Fred L. Mannering
      Time-constant assumptions in discrete-response heterogeneity models can often be violated. To address this, a time-varying heterogeneity approach to model unobserved heterogeneity in ordered response data is considered. A Markov switching random parameters structure (which accounts for heterogeneity across observations) is proposed to accommodate both time-varying and time-constant (cross-sectional) unobserved heterogeneity in an ordered discrete-response probability model. A data augmented Markov Chain Monte Carlo algorithm for non-linear model estimation is developed to facilitate model estimation. The performance of the cross-sectional heterogeneity model and time-varying heterogeneity model are examined with vehicle crash-injury severity data. The time-varying heterogeneity model (Markov switching random parameters ordered probit) is found to provide the best overall model fit. Two roadway safety states are shown to exist and roadway segments transition between these two states according to Markov transition probabilities. The results demonstrate considerable promise for Markov switching models in a wide variety of applications.


      PubDate: 2014-07-24T19:15:19Z
       
  • Public transport vehicle scheduling featuring multiple vehicle types
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Stephan Hassold , Avishai (Avi) Ceder
      Vehicle scheduling is a crucial step of the public transport planning process because it results in the number of vehicles required, thus it is directly related to fixed cost and labor cost. It is desirable, therefore, to minimize the number of vehicles used and operational cost. This paper proposes a new methodology for the multiple vehicle types vehicle scheduling problem (MVT-VSP). The methodology is based on a minimum-cost network flow model utilizing sets of Pareto-optimal timetables for individual bus lines. Given a fixed fleet size the suggested methodology also allows a selection of the optimal timetable. The method developed enables to stipulate the use of a particular vehicle type for a trip or to allow for a substitution either by a larger vehicle or a combination of smaller vehicles with the same or higher total capacity. Moreover, a variation of the method portrayed makes it possible to construct sub-optimal timetables given a reduction of the vehicle-scheduling cost. It is demonstrated that a substitution of vehicles is beneficial and can lead to significant cost reductions in the range of more than 27%. The suggested methodology is applied to a real-life case study in Auckland, New Zealand, and the results show improvements of greater than 15% in terms of the cost of fleet compared with vehicle schedules that are provided by standard models.


      PubDate: 2014-07-24T19:15:19Z
       
  • Braess paradox under the boundedly rational user equilibria
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Xuan Di , Xiaozheng He , Xiaolei Guo , Henry X. Liu
      The Braess paradox and its variants have been studied under the perfectly rational behavior assumption. However, when the perfect rationality assumption is relaxed to bounded rationality, which assumes that travelers can take any route whose travel cost is within an ‘indifference band’ of the shortest path cost, it remains unclear under what conditions the Braess paradox occurs. This paper fills this gap by exploring relationships between the occurrence of the Braess paradox and the indifference band as well as the demand level in the setting of the boundedly rational user equilibrium (BRUE). The definition of the Braess paradox is extended based on planners’ risk-taking attitudes, i.e., risk-averse, risk-prone and risk-neutral, due to the non-uniqueness of BRUE. The paradox occurrence conditions under different risk-taking attitudes are investigated using the classical Braess network and compared with those under the user equilibrium. Then we generalize the paradox conditions to simple and ordinary grid networks with regular Bureau of Public Roads (BPR) link performance functions. The impact of the link cost congestion sensitivity along with the indfference band on the occurrence of the Braess paradox is also studied.


      PubDate: 2014-07-24T19:15:19Z
       
  • A new schedule-based transit assignment model with travel strategies and
           supply uncertainties
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Younes Hamdouch , W.Y. Szeto , Y. Jiang
      This paper proposes a new scheduled-based transit assignment model. Unlike other schedule-based models in the literature, we consider supply uncertainties and assume that users adopt strategies to travel from their origins to their destinations. We present an analytical formulation to ensure that on-board passengers continuing to the next stop have priority and waiting passengers are loaded on a first-come-first-serve basis. We propose an analytical model that captures the stochastic nature of the transit schedules and in-vehicle travel times due to road conditions, incidents, or adverse weather. We adopt a mean variance approach that can consider the covariance of travel time between links in a space–time graph but still lead to a robust transit network loading procedure when optimal strategies are adopted. The proposed model is formulated as a user equilibrium problem and solved by an MSA-type algorithm. Numerical results are reported to show the effects of supply uncertainties on the travel strategies and departure times of passengers.


      PubDate: 2014-07-24T19:15:19Z
       
  • A new estimation approach to integrate latent psychological constructs in
           choice modeling
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Chandra R. Bhat , Subodh K. Dubey
      In the current paper, we propose a new multinomial probit-based model formulation for integrated choice and latent variable (ICLV) models, which, as we show in the paper, has several important advantages relative to the traditional logit kernel-based ICLV formulation. Combining this MNP-based ICLV model formulation with Bhat’s maximum approximate composite marginal likelihood (MACML) inference approach resolves the specification and estimation challenges that are typically encountered with the traditional ICLV formulation estimated using simulation approaches. Our proposed approach can provide very substantial computational time advantages, because the dimensionality of integration in the log-likelihood function is independent of the number of latent variables. Further, our proposed approach easily accommodates ordinal indicators for the latent variables, as well as combinations of ordinal and continuous response indicators. The approach can be extended in a relatively straightforward fashion to also include nominal indicator variables. A simulation exercise in the virtual context of travel mode choice shows that the MACML inference approach is very effective at recovering parameters. The time for convergence is of the order of 30–80min for sample sizes ranging from 500 observations to 2000 observations, in contrast to much longer times for convergence experienced in typical ICLV model estimations.


      PubDate: 2014-07-24T19:15:19Z
       
  • Scheduled paratransit transport systems
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): G. Dikas , I. Minis
      In this paper we focus on ways to provide individualized services to people with mobility challenges using existing modes of public transport. We study the design of an interesting case, in which a bus operating in a public transport route may diverge from its nominal path to pick-up passengers with limited mobility and drop them off at their destination. We have modeled the design problem by a mixed integer-linear program, and we developed an exact Branch and Price approach to solve it to optimality. The proposed approach includes a labeling algorithm in which we introduced appropriate dominance rules, which do not compromise optimality. We have compared the efficiency of our approach with that of related algorithms from the literature. Furthermore, we have used the proposed approach to study key aspects of the system design problem, such as the effect of various constraints on the service level, and the tuning of the system’s parameters to address different transport environments.


      PubDate: 2014-07-24T19:15:19Z
       
  • Distributed coordinated in-vehicle online routing using mixed-strategy
           congestion game
    • Abstract: Publication date: September 2014
      Source:Transportation Research Part B: Methodological, Volume 67
      Author(s): Lili Du , Lanshan Han , Xiang-Yang Li
      This study proposes a coordinated online in-vehicle routing mechanism for smart vehicles with real-time information exchange and portable computation capabilities. The proposed coordinated routing mechanism incorporates a discrete choice model to account for drivers’ behavior, and is implemented by a simultaneously-updating distributed algorithm. This study shows the existence of an equilibrium coordinated routing decision for the mixed-strategy routing game and the convergence of the distributed algorithm to the equilibrium routing decision, assuming individual smart vehicles are selfish players seeking to minimize their own travel time. Numerical experiments conducted based on Sioux Falls city network indicate that the proposed distributed algorithm converges quickly under different smart vehicle penetrations, thus it possesses a great potential for online applications. Moreover, the proposed coordinated routing mechanism outperforms traditional independent selfish-routing mechanism; it reduces travel time for both overall system and individual vehicles, which represents the core idea of Intelligent Transportation Systems (ITS).


      PubDate: 2014-07-24T19:15:19Z
       
  • Bottleneck model revisited: An activity-based perspective
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Zhi-Chun Li , William H.K. Lam , S.C. Wong
      The timing of commuting trips made during morning and evening peaks has typically been investigated using Vickrey’s bottleneck model. However, in the conventional trip-based approach, the decisions that commuters make during the day about their activity schedules and time use are not explicitly considered. This study extends the bottleneck model to address the scheduling problem of commuters’ morning home-to-work and evening work-to-home journeys by using an activity-based approach. A day-long activity-travel scheduling model is proposed for the simultaneous determination of departure times for morning and evening commutes, together with allocations of time during the day among travel and activities undertaken at home or at the workplace. The proposed model maximizes the total net utility of the home-based tour, which is the difference between the benefits derived from participating in activities and the disutility incurred by travel between activity locations. The properties of the model solution are analytically explored and compared with the conventional bottleneck model for a special case with constant marginal-activity utility. For the case with linear marginal-activity utility, we develop a heuristic procedure to seek the equilibrium scheduling solution. We also explore the effects of marginal-work utility (or the employees’ average wage level) and of flexible work-hour schemes on the scheduling problem in relation to the morning and evening commuting tours.


      PubDate: 2014-07-24T19:15:19Z
       
  • A Generalized Random Regret Minimization model
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Caspar G. Chorus
      This paper presents, discusses and tests a Generalized Random Regret Minimization (G-RRM) model. The G-RRM model is created by recasting a fixed constant in the attribute-specific regret functions of the conventional RRM model, into an attribute-specific regret-weight. Given that regret-weights of different attributes can take on different values, the G-RRM model allows for additional flexibility when compared to the conventional RRM model, as it allows the researcher to capture choice behavior that equals that implied by, respectively, the canonical linear-in-parameters Random Utility Maximization (RUM) model, the conventional Random Regret Minimization (RRM) model, and hybrid RUM–RRM specifications. Furthermore, for particular values of the attribute-specific regret-weights, models are obtained where regret minimization (i.e., reference dependency and asymmetry of preferences) is present for the attribute, but in a less pronounced way than in a conventional RRM model. When regret-weights are written as binary logit functions, the G-RRM model can be estimated on choice data using conventional software packages. As an empirical proof of concept, the G-RRM model is estimated on a stated route choice dataset as well as on synthetic data, and its outcomes are compared with RUM, RRM, hybrid RUM–RRM and latent class counterparts.


      PubDate: 2014-07-24T19:15:19Z
       
  • Non-planar hole-generated networks and link flow observability based on
           link counters
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Enrique Castillo , Aida Calviño , Hong K. Lo , José María Menéndez , Zacarías Grande
      The concepts of hole, cycle added link and non-planar hole-generated network are introduced for the first time and used to determine (a) the immediate solution of the node conservation equations in terms of hole and cycle added vectors, and (b) the paths as linear combinations of hole vectors. Two equivalent formulas to obtain the number of links to be observed for complete link observability in non-planar hole-generated networks are given in terms of the numbers of links, nodes, holes, cycle added links and centroid node types. These formulas are applicable without any limitation in the number of centroids and possible link connections. Some simple methods are given to obtain first the maximum number of linearly independent (l.i.) paths and next a minimum set of links to be counted in order to get observability of all link flows. It is demonstrated that the number of l.i. paths in a non-planar hole-generated network coincides with the number of holes and cycle added links in the network and that any path can be obtained by linear combinations of the vectors associated with the hole and cycle added links. The methods are illustrated by their application to several networks.


      PubDate: 2014-07-24T19:15:19Z
       
  • A probabilistic stationary speed–density relation based on
           Newell’s simplified car-following model
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Saif Eddin Jabari , Jianfeng Zheng , Henry X. Liu
      Probabilistic models describing macroscopic traffic flow have proven useful both in practice and in theory. In theoretical investigations of wide-scatter in flow–density data, the statistical features of flow density relations have played a central role. In real-time estimation and traffic forecasting applications, probabilistic extensions of macroscopic relations are widely used. However, how to obtain such relations, in a manner that results in physically reasonable behavior has not been addressed. This paper presents the derivation of probabilistic macroscopic traffic flow relations from Newell’s simplified car-following model. The probabilistic nature of the model allows for investigating the impact of driver heterogeneity on macroscopic relations of traffic flow. The physical features of the model are verified analytically and shown to produce behavior which is consistent with well-established traffic flow principles. An empirical investigation is carried out using trajectory data from the New Generation SIMulation (NGSIM) program and the model’s ability to reproduce real-world traffic data is validated.


      PubDate: 2014-07-24T19:15:19Z
       
  • Cycle-by-cycle intersection queue length distribution estimation using
           sample travel times
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Peng Hao , Xuegang (Jeff) Ban , Dong Guo , Qiang Ji
      We propose Bayesian Network based methods for estimating the cycle by cycle queue length distribution of a signalized intersection. Queue length here is defined as the number of vehicles in a cycle which have experienced significant delays. The data input to the methods are sample travel times from mobile traffic sensors collected between an upstream location and a downstream location of the intersection. The proposed methods first classify traffic conditions and sample scenarios to seven cases. BN models are then developed for each case. The methods are tested using data from NGSIM, a field experiment, and microscopic traffic simulation. The results are satisfactory compared with two specific queue length estimation methods previously developed in the literature.


      PubDate: 2014-07-24T19:15:19Z
       
  • Revisiting the empirical fundamental relationship
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Benjamin Coifman
      This paper develops a new methodology for deriving an empirical fundamental relationship from vehicle detector data. The new methodology seeks to address several sources of noise present in conventional measures of the traffic state that arise from the data aggregation process, e.g., averaging across all vehicles over a fixed time period. In the new methodology vehicles are no longer taken successively in the order in which they arrived and there is no requirement to seek out stationary traffic conditions; rather, the traffic state is measured over the headway for each individual vehicle passage and the vehicles are grouped by similar lengths and speeds before aggregation. Care is also taken to exclude measurements that might be corrupted by detector errors. The result is a homogeneous set of vehicles and speeds in each bin. While conventional fixed time averages may have fewer than 10 vehicles in a sample, the new binning process ensures a large number of vehicles in each bin before aggregation. We calculate the median flow and median occupancy for each combined length and speed bin. Then we connect these median points across all of the speed bins for a given vehicle length to derive the empirical fundamental relationship for that length. This use of the median is also important; unlike conventional aggregation techniques that find the average, the median is far less sensitive to outliers arising from uncommon driver behavior or occasional detector errors. The work is applied to real data from a dual loop detector station and it yields consistent results across 18 independent days, 4 independent lanes, and 7 independent length bins. These empirical results from non-stationary traffic are also shown to be consistent with hypothetical results generated with homogeneous vehicles under stationary traffic conditions.


      PubDate: 2014-07-24T19:15:19Z
       
  • Pre-trip information and route-choice decisions with stochastic travel
           conditions: Experiment
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Amnon Rapoport , Eyran J. Gisches , Terry Daniel , Robin Lindsey
      This paper studies the effects of pre-trip information on route-choice decisions when travel conditions on two alternative congestible routes vary unpredictably. It presents and discusses an experiment designed to test a model recently proposed in a companion paper by Lindsey et al. (2013). That model predicts that if free-flow costs on the two routes are unequal, travel cost functions are convex, and capacities are positively and perfectly correlated, then in equilibrium, paradoxically, total expected travel costs increase with the provision of pre-trip information about travel conditions on each route. By contrast, when capacities vary independently, total expected travel costs are predicted to decrease with pre-trip information. We reformulate the model for finite populations, and then test and find support for its predictions in an experiment where under different capacity scenarios, and with and without pre-trip information, subjects are asked to choose routes with payoff contingent on their performance.


      PubDate: 2014-07-24T19:15:19Z
       
  • Joint optimization of pavement design, resurfacing and maintenance
           strategies with history-dependent deterioration models
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Jinwoo Lee , Samer Madanat
      The subject of this paper is the joint optimization of pavement design, maintenance and resurfacing (M&R) strategies. This problem is solved for continuous pavement state, continuous time, infinite planning horizon and non-Markovian (history-dependent) pavement deterioration model. This paper presents a mathematical formulation of the joint optimization problem to minimize the total discounted lifecycle costs, using a combination of analytical and numerical tools. The lifecycle costs include both user costs and agency (construction, resurfacing and maintenance) costs. This paper shows that resurfacing schedule converges to a steady state after a few resurfacing cycles. The research results should be of use to developing countries in the process of expanding their highway networks facing multiple constraints.


      PubDate: 2014-07-24T19:15:19Z
       
  • On the impacts of bus stops near signalized intersections: Models of car
           and bus delays
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Weihua Gu , Vikash V. Gayah , Michael J. Cassidy , Nathalie Saade
      Models are formulated to predict the added vehicle and person delays that can occur when a bus stop is located a short distance upstream or downstream of a signalized intersection. Included in the set of models are those that predict the expected delays that cars collectively incur when a bus blocks one of multiple lanes while loading and unloading passengers at the stop. Others in this set predict the expected added delays incurred by the bus due to car queues. Each model is consistent with the kinematic wave theory of highway traffic, as is confirmed through a battery of tests. And each accounts for the randomness in both, bus arrival times at a stop, and the durations that buses dwell there to serve passengers. Though the models are analytical in form, solutions come through iteration. Hence model applications are performed with the aid of a computer. The applications presented herein show that bus delays can often be shortened by placing the bus stop downstream of its neighboring signalized intersection, rather than upstream of it. In contrast, car delays are often shortened by placing the stop some distance upstream of the intersection, rather than downstream. We further show how exerting a measure of control on bus arrivals can further enhance these benefits to cars without further delaying the buses. The models are also used to assess the net person delays collectively incurred by car- and bus-travelers.


      PubDate: 2014-07-24T19:15:19Z
       
  • Continuous-time dynamic system optimum for single-destination traffic
           networks with queue spillbacks
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Rui Ma , Xuegang (Jeff) Ban , Jong-Shi Pang
      Dynamic system optimum (DSO) is a special case of the general dynamic traffic assignment (DTA). It predicts the optimal traffic states of a network under time-dependent traffic conditions from the perspective of the entire system. An optimal control framework is proposed in this paper for the continuous-time DSO problem for single-destination traffic networks. Departure time choice is part of this DSO model. Double-queue model is applied to capture the impact of downstream congestion and possible queue spillbacks. Feasibility conditions and model properties are discussed. A constructive procedure to compute a free-flow DSO solution is also proposed. A discretization method is described to the continuous-time systems and numerical results on two test networks are shown.


      PubDate: 2014-07-24T19:15:19Z
       
  • Integration of conventional and flexible bus services with timed transfers
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Myungseob (Edward) Kim , Paul Schonfeld
      Conventional bus services, which have fixed routes and fixed service schedules, and flexible bus services, which provide doorstep services, have different advantages and disadvantages, with conventional services being generally preferable at high demand densities and flexible services being preferable at low densities. By efficiently integrating conventional and flexible services and thus matching service type to various regions, the total cost of transit services may be significantly reduced, especially in regions with substantial demand variations over time and space. Additionally, transit passengers must often transfer among routes because it is prohibitively expensive to provide direct routes for among all origin–destination pairs in large networks. Coordinating vehicle arrivals at transfer terminals can greatly reduce the transfer times of passengers. In this paper, probabilistic optimization models, which are proposed to deal with stochastic variability in travel times and wait times, are formulated for integrating and coordinating bus transit services for one terminal and multiple local regions. Solutions for decision variables, which include the selected service type for particular regions, the vehicle size, the number of zones, headways, fleet, and slack times, are found here with analytic optimization or numerical methods. The proposed models generate either common headway or integer-ratio headway solutions for timed transfer coordination based on the given demand. A genetic algorithm is proposed as a solution method and tested with numerical examples.


      PubDate: 2014-07-24T19:15:19Z
       
  • Estimation of mean and covariance of peak hour origin–destination
           demands from day-to-day traffic counts
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Hu Shao , William H.K. Lam , Agachai Sumalee , Anthony Chen , Martin L. Hazelton
      This paper proposes a generalized model to estimate the peak hour origin–destination (OD) traffic demand variation from day-to-day hourly traffic counts throughout the whole year. Different from the conventional OD estimation methods, the proposed modeling approach aims to estimate not only the mean but also the variation (in terms of covariance matrix) of the OD demands during the same peak hour periods due to day-to-day fluctuation over the whole year. For this purpose, this paper fully considers the first- and second-order statistical properties of the day-to-day hourly traffic count data so as to capture the stochastic characteristics of the OD demands. The proposed model is formulated as a bi-level optimization problem. In the upper-level problem, a weighted least squares method is used to estimate the mean and covariance matrix of the OD demands. In the lower-level problem, a reliability-based traffic assignment model is adopted to take account of travelers’ risk-taking path choice behaviors under OD demand variation. A heuristic iterative estimation-assignment algorithm is proposed for solving the bi-level optimization problem. Numerical examples are presented to illustrate the applications of the proposed model for assessment of network performance over the whole year.


      PubDate: 2014-07-24T19:15:19Z
       
  • A joint count-continuous model of travel behavior with selection based on
           a multinomial probit residential density choice model
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Chandra R. Bhat , Sebastian Astroza , Raghuprasad Sidharthan , Mohammad Jobair Bin Alam , Waleed H. Khushefati
      This paper formulates a multidimensional choice model system that is capable of handling multiple nominal variables, multiple count dependent variables, and multiple continuous dependent variables. The system takes the form of a treatment-outcome selection system with multiple treatments and multiple outcome variables. The Maximum Approximate Composite Marginal Likelihood (MACML) approach is proposed in estimation, and a simulation experiment is undertaken to evaluate the ability of the MACML method to recover the model parameters in such integrated systems. These experiments show that our estimation approach recovers the underlying parameters very well and is efficient from an econometric perspective. The parametric model system proposed in the paper is applied to an analysis of household-level decisions on residential location, motorized vehicle ownership, the number of daily motorized tours, the number of daily non-motorized tours, and the average distance for the motorized tours. The empirical analysis uses the NHTS 2009 data from the San Francisco Bay area. Model estimation results show that the choice dimensions considered in this paper are inter-related, both through direct observed structural relationships and through correlations across unobserved factors (error terms) affecting multiple choice dimensions. The significant presence of self-selection effects (endogeneity) suggests that modeling the various choice processes in an independent sequence of models is not reflective of the true relationships that exist across these choice dimensions, as also reinforced through the computation of treatment effects in the paper.


      PubDate: 2014-07-24T19:15:19Z
       
  • Adding a new station and a road link to a road–rail network in the
           presence of modal competition
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Federico Perea , Juan A. Mesa , Gilbert Laporte
      In this paper we study the problem of locating a new station on an existing rail corridor and a new junction on an existing road network, and connecting them with a new road segment under a budget constraint. We consider three objective functions and the corresponding optimization problems, which are modeled by means of mixed integer non-linear programs. For small instances, the models can be solved directly by a standard solver. For large instances, an enumerative algorithm based on a discretization of the problem is proposed. Computational experiments show that the latter approach yields high quality solutions within short computing times.


      PubDate: 2014-07-24T19:15:19Z
       
  • Cost scaling based successive approximation algorithm for the traffic
           assignment problem
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68
      Author(s): Hong Zheng , Srinivas Peeta
      This paper presents a cost scaling based successive approximation algorithm, called ε-BA (ε-optimal bush algorithm), to solve the user equilibrium traffic assignment problem by successively refining ε-optimal flows. As ε reduces to zero, the user equilibrium solution is reached. The proposed method is a variant of bush-based algorithms, and also a variant of the min-mean cycle algorithm to solve the min-cost flow by successive approximation. In ε-BA, the restricted master problem, implying traffic equilibration restricted on a bush, is solved to ε-optimality by cost scaling before bush reconstruction. We show that ε-BA can reduce the number of flow operations substantially in contrast to Dial’s Algorithm B, as the former operates flows on a set of deliberately selected cycles whose mean values are sufficiently small. Further, the bushes can be constructed effectively even if the restricted master problem is not solved to a high level of convergence, by leveraging the ε-optimality condition. As a result, the algorithm can solve a highly precise solution with faster convergence on large-scale networks compared to our implementation of Dial’s Algorithm B.


      PubDate: 2014-07-24T19:15:19Z
       
  • System optimal dynamic traffic assignment: Properties and solution
           procedures in the case of a many-to-one network
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65
      Author(s): Wei Shen , H.M. Zhang
      Thanks to its high dimensionality and a usually non-convex constraint set, system optimal dynamic traffic assignment remains one of the most challenging problems in transportation research. This paper identifies two fundamental properties of the problem and uses them to design an efficient solution procedure. We first show that the non-convexity of the problem can be circumvented by first solving a relaxed problem and then applying a traffic holding elimination procedure to obtain the solution(s) of the original problem. To efficiently solve the relaxed problem, we explore the relationship between the relaxed problems based on different traffic flow models (PQ, SQ, CTM) and a minimal cost flow (MCF) problem for a special space-expansion network. It is shown that all the four problem formulations produce the same minimal system cost and share one common solution which does not involve inside queues in the network. Efficient solution algorithms such as the network simplex method can be applied to solve the MCF problem and identify such an optimal traffic pattern. Numerical examples are also presented to demonstrate the efficiency of the proposed solution procedure.


      PubDate: 2014-04-28T05:10:10Z
       
  • Estimating the value of travel time and of travel time reliability in road
           networks
    • Abstract: Publication date: Available online 7 February 2014
      Source:Transportation Research Part B: Methodological
      Author(s): Kenetsu Uchida
      This study proposes two network models which simultaneously estimate the value of travel time and of travel time reliability based on the risk-averse driver’s route choice behavior. The first model is formulated as a utility maximization problem under monotonic and separable link travel times, whereas the second model is formulated as a utility maximization problem under non-monotonic and non-separable link travel times. The proposed models have the same structure as a user equilibrium (UE) traffic assignment problem with elastic demand. It is shown that the first model, which addresses independent stochastic capacity, is formulated as an optimization problem with a unique solution and is solved by using an algorithm for a UE traffic assignment problem with fixed demand. The second model, which addresses both stochastic Origin–Destination (O–D) flow and stochastic link capacity, is formulated as a nonlinear complementary problem. O–D demand functions formulated in the proposed models are derived from the utility maximization behavior of the driver in the network. Therefore, the network models proposed in this study are consistent with those of studies that address the value of travel time and of travel time reliability based on utility maximization behavior without considering the driver’s route choice. Numerical experiments are carried out to demonstrate the models presented in this study.


      PubDate: 2014-04-28T05:10:10Z
       
  • On the stochastic network equilibrium with heterogeneous choice inertia
    • Abstract: Publication date: Available online 28 February 2014
      Source:Transportation Research Part B: Methodological
      Author(s): Chi Xie , Zugang Liu
      As an alternative effort for quantifying recurrent traffic dynamics caused by network variations and analyzing the impact on the network performance from information provision, we describe in this paper a new equilibrium modeling scheme for stochastic networks with a finite number of states, which takes into account the behavioral inertia. A finite-dimensional variational inequality model is formulated to describe the cross-state equilibrium conditions among heterogeneous travelers with different inertial degrees and knowledge structures. Our model allows for traveler’s partial understanding and inertial effect in perceiving varying network conditions and provides a different perspective (from existing stochastic and Markovian network equilibrium approaches) to describe traffic flow variations across multiple network scenarios. A disaggregate simplicial decomposition algorithm is suggested to solve the variational inequality problem. Numerical results from a few stochastic network examples demonstrate the validity and effectiveness of our methodology in modeling the inertia phenomenon within route choice behavior and the efficacy of using traveler information systems to eliminate the inertia effect.


      PubDate: 2014-04-28T05:10:10Z
       
  • A bilevel model for multivariate risk analysis of pedestrians’
           crossing behavior at signalized intersections
    • Abstract: Publication date: July 2014
      Source:Transportation Research Part B: Methodological, Volume 65
      Author(s): Baibing Li
      Pedestrians who cross streets during the red-man phase of traffic light signals expose themselves to safety and health hazards and hence are considered to be at risk. Pedestrians’ street-crossing behavior is in general the outcome of interaction between pedestrians and vehicles: the gaps between vehicles provide an opportunity for pedestrians to cross the street, and pedestrians may or may not accept the street-crossing risk during the red-man phase. In this paper, we propose a multivariate method to investigate pedestrians’ risk exposure associated with unsafe crossings. The proposed method consists of two hierarchically interconnected generalized linear models that characterize two different facets of the unsafe crossing behavior. It gauges pedestrians’ attitudes toward risk-taking and also measures the impact of potential risk factors on pedestrians’ intended waiting times during the red-man phase of the traffic lights. A Bayesian approach with the data augmentation method is used to draw statistical inference for the parameters associated with risk exposure. The proposed method is illustrated using field traffic data.


      PubDate: 2014-04-28T05:10:10Z
       
  • Pareto efficiency of reliability-based traffic equilibria and risk-taking
           behavior of travelers
    • Abstract: Publication date: Available online 7 January 2014
      Source:Transportation Research Part B: Methodological
      Author(s): Zhijia Tan , Hai Yang , Renyong Guo
      This paper investigates the Pareto efficiency of the various reliability-based traffic equilibria proposed in the literature and the risk-taking behavior of travelers. Reliability indexes such as the percentile travel time (PTT), travel time budget (TTB), mean excess travel time (METT) and the quadratic disutility function (QDF) are examined in terms of the mean and standard deviation (SD) of travel times. The downward sloping mean-SD indifference curve is introduced to geometrically analyze the risk-taking behavior of travelers. Both the diversifying and plunging behaviors of risk-averse travelers are investigated by examining the curvature of the mean-SD indifference curves at traffic equilibria based on the PTT, TTB, METT and QDF. Several specific probability distributions are adopted to elucidate the theoretical results obtained.


      PubDate: 2014-01-08T21:27:35Z
       
  • Depot location in degradable transport networks
    • Abstract: Publication date: Available online 15 December 2013
      Source:Transportation Research Part B: Methodological
      Author(s): Michael G.H. Bell , Achille Fonzone , Chrisanthi Polyzoni
      Areas subject to natural or man-made disasters, such as earthquakes, fires, floods or attacks, are reliant on the residual transport network for the rescue of survivors and subsequent recovery. Pre-disaster planning requires assumptions about how the transport network may degrade. This paper presents a game theoretic approach modelling network degradation and applies this to depot location, with a case study based on Sichuan province in China, which is prone to earthquakes. To facilitate a cautious approach to depot location, the method assumes that the transport network is subject to attack by node-specific demons with the power to degrade links. The mixed strategy Nash equilibrium for the non-cooperative zero sum game between dispatchers and demons is used to define rescue hyperpaths. These in turn define the best depot locations. Two forms of the drop heuristic are used to find good depot locations.


      PubDate: 2013-12-19T18:25:09Z
       
  • Ferry service network design with stochastic demand under user equilibrium
           flows
    • Abstract: Publication date: Available online 2 December 2013
      Source:Transportation Research Part B: Methodological
      Author(s): Kun An , Hong K. Lo
      This paper develops a service reliability-based formulation for ferry service network design with stochastic demand under user equilibrium flows while considering two types of services, regular and ad hoc. Regular services operate with a fixed schedule; whereas ad hoc services are those subcontracted or outsourced to a third party and have a higher unit cost. Two ad hoc provision schemes are studied. Scheme A considers that the demand information is known in advance by passenger reservation, and the company makes use of this information to plan for ad hoc services. In Scheme B, the demand realization is only known as passengers arrive at the piers and the company calls upon ad hoc services in case of demand overflow. In Scheme A, we utilize the notion of service reliability (SR) to address the issue of demand uncertainty and formulate the problem as a two-phase stochastic program in which the schedule of regular services and ad hoc services are derived sequentially. The user equilibrium (UE) assignment with capacity constraint is formulated via a linear programming (LP) approach considering overflow delays. A SR-based gradient solution approach is developed to solve the model. Scheme B, as expected, requires more resources to operate, for which a SR-based non-linear model is developed. The value of reservation to the company is defined as the operating cost difference between these two schemes. We apply the methods to ferry service network design in Hong Kong, and then compare the UE (Scheme A) and system optimal (SO) solutions, in terms of service deployment and computation time, to contrast the solution quality arising from the inclusion of equilibrium flows. The value of advance reservation information between Scheme A and Scheme B is presented as well.


      PubDate: 2013-12-03T14:16:14Z
       
 
 
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