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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: 19)
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: 5)
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: 4)
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  
International Journal of Sustainable Transportation     Hybrid Journal   (Followers: 4)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 14)
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: 3)
Journal of Transport & Health     Hybrid Journal   (Followers: 1)
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: 13)
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: 8)
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: 4)
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: 14)
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: 22)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 21)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 13)
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 26)
Transportation Science     Full-text available via subscription   (Followers: 15)
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
   [23 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0191-2615
     Published by Elsevier Homepage  [2571 journals]   [SJR: 3.08]   [H-I: 60]
  • 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
       
  • Post-disaster evacuation and temporary resettlement considering panic and
           panic spread
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Zhi-Hua Hu , Jiuh-Biing Sheu , Ling Xiao
      After a disaster, a huge number of homeless victims should be evacuated to temporary resettlement sites. However, because the number of temporary shelters is insufficient, as are shelter building capabilities, victims must be evacuated and resettled in batches. The perceived psychological penalty to victims may increase due to heightened panic when waiting for evacuation and resettlement, whereas psychological interventions can decrease the magnitude of this panic. Based on the susceptible–infective-removal model, panic spread among homeless victims and other disaster-affected people is modeled, while considering the effects of psychological interventions on panic spread. A function is derived to compute the increase in the number of victims to be evacuated due to panic spread. A novel mixed-integer linear program is constructed for multi-step evacuation and temporary resettlement under minimization of panic-induced psychological penalty cost, psychological intervention cost, and costs associated with transportation and building shelters. The model is solved by aggregating objectives into a single objective by assigning weights to these objectives. With Wenchuan County as the test case, the epicenter of the 2008 Sichuan earthquake, the influence and the sensitivity of parameters, tradeoff among costs, and the effects of various functions of panic strength on psychological penalty and monetary costs are assessed using six experimental scenarios. Analytical results reveal the complexity and managerial insights gained by applying the proposed method to post-disaster evacuation and temporary resettlement.


      PubDate: 2014-09-23T01:29:01Z
       
  • 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
       
  • Block time reliability and scheduled block time setting
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Lu Hao , Mark Hansen
      While in ground transportation the concept of reliability has been extensively studied, there is little literature in air transportation. Scheduled block time (SBT) setting is a crucial part in airlines’ scheduling. Interviews with an airline and relevant work in ground transportation have shown that SBT and the historical block time distribution, reflecting block time reliability, have a close relationship. This paper investigates how the change in actual block time distribution will affect SBT and system performance. Firstly this relationship is studied with empirical data and multiple regression models. The distribution of the historical block time for a flight is depicted by the difference between every 10th percentiles. We found that gate delay plays a minor role in setting SBT and that SBTs have decreasing sensitivity to historical flight times toward the right tail of the distribution. To specifically link SBT setting with the flight’s on-time performance, a SBT adjustment model is further developed. Poor on-time performance leads to increased SBT in the next year. With the behavior model results showing that both the median block time and the “inner right tail” of the distribution affect SBT setting, an impact study is conducted to validate these impacts with historical data. The impact of historical block time distribution on SBT is validated with real data in year 2006–2008 and 2009–2011. Furthermore, by studying the flight performance difference based on different changes in SBT, we conclude that ignoring the impact on SBT changes when considering potential benefits of improved block time distribution could lead to inaccurate results.


      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
       
  • Optimal joint distance and time toll for cordon-based congestion pricing
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Zhiyuan Liu , Shuaian Wang , Qiang Meng
      This paper addresses the optimal toll design problem for the cordon-based congestion pricing scheme, where both a time-toll and a nonlinear distance-toll (i.e., joint distance and time toll) are levied for each network user’s trip in a pricing cordon. The users’ route choice behaviour is assumed to follow the Logit-based stochastic user equilibrium (SUE). We first propose a link-based convex programming model for the Logit-based SUE problem with a joint distance and time toll pattern. A mathematical program with equilibrium constraints (MPEC) is developed to formulate the optimal joint distance and time toll design problem. The developed MPEC model is equivalently transformed into a semi-infinite programming (SIP) model. A global optimization method named Incremental Constraint Method (ICM) is designed for solving the SIP model. Finally, two numerical examples are used to assess the proposed methodology.


      PubDate: 2014-09-19T01:04:44Z
       
  • Editorial Board
    • Abstract: Publication date: October 2014
      Source:Transportation Research Part B: Methodological, Volume 68




      PubDate: 2014-09-14T00:24:12Z
       
  • Singularities in kinematic wave theory: Solution properties, extended
           methods and duality revisited
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Carlos F. Daganzo
      According to Euler–Lagrange duality principle of kinematic wave (KW) theory any well-posed initial value traffic flow problem can be solved with the same methods either on the time–space (Euler) plane or the time vs vehicle number (Lagrange) plane. To achieve this symmetry the model parameters and the boundary data need to be expressed in a form appropriate for each plane. It turns out, however, that when boundary data that are bounded in one plane are transformed for the other, singular points with infinite density sometimes arise. Duality theory indicates that solutions to these problems must exist and be unique. Therefore, these solutions should be characterized. The paper shows that the only added feature of these solutions is a new type of shock that can contain mass and we call a supershock. Nothing else is different. The evolution laws of these shocks are described. Solution methods based on these laws for problems with singularities are also presented. The methods apply to problems with monotone speed–density relations and not necessarily concave fundamental diagrams. In accordance with duality theory they can be used with both, the Euler and Lagrange versions of a problem.


      PubDate: 2014-09-08T23:48:12Z
       
  • A macroscopic loading model for time-varying pedestrian flows in public
           walking areas
    • Abstract: Publication date: November 2014
      Source:Transportation Research Part B: Methodological, Volume 69
      Author(s): Flurin S. Hänseler , Michel Bierlaire , Bilal Farooq , Thomas Mühlematter
      A macroscopic loading model applicable to time-dependent and congested pedestrian flows in public walking areas is proposed. Building on the continuum theory of pedestrian flows and the cell transmission model for car traffic, an isotropic framework is developed that can describe the simultaneous and potentially conflicting propagation of multiple pedestrian groups. The model is formulated at the aggregate level and thus computationally cheap, which is advantageous for studying large-scale problems. A detailed analysis of several basic flow patterns including counter- and cross flows, as well as two generic scenarios involving a corner- and a bottleneck flow is carried out. Various behavioral patterns ranging from disciplined queueing to impatient jostling can be realistically reproduced. Following a systematic model calibration, two case studies involving a Swiss railway station and a Dutch bottleneck flow experiment are presented. A comparison with the social force model and pedestrian tracking data shows a good performance of the proposed model with respect to predictions of travel time and density.


      PubDate: 2014-09-08T23:48:12Z
       
  • 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
       
  • 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
       
 
 
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