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  Subjects -> TRANSPORTATION (Total: 162 journals)
    - AIR TRANSPORT (7 journals)
    - AUTOMOBILES (20 journals)
    - RAILROADS (4 journals)
    - ROADS AND TRAFFIC (4 journals)
    - SHIPS AND SHIPPING (28 journals)
    - TRANSPORTATION (99 journals)

TRANSPORTATION (99 journals)

Accident Analysis & Prevention     Partially Free   (Followers: 40)
AI & Society     Hybrid Journal   (Followers: 2)
Analytic Methods in Accident Research     Hybrid Journal  
Archives of Transport     Open Access   (Followers: 5)
Bitácora Urbano-Territorial     Open Access   (Followers: 2)
Botswana Journal of Technology     Full-text available via subscription  
Case Studies on Transport Policy     Hybrid Journal  
Cities in the 21st Century     Open Access   (Followers: 11)
Economics of Transportation     Partially Free   (Followers: 10)
Emission Control Science and Technology     Hybrid Journal  
EURO Journal of Transportation and Logistics     Hybrid Journal   (Followers: 4)
European Transport Research Review     Open Access   (Followers: 13)
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: 5)
International Innovation – Transport     Open Access   (Followers: 4)
International Journal of Applied Logistics     Full-text available via subscription   (Followers: 5)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 4)
International Journal of Critical Infrastructure Protection     Hybrid Journal   (Followers: 6)
International Journal of e-Navigation and Maritime Economy     Open Access  
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 5)
International Journal of Electronic Transport     Hybrid Journal   (Followers: 2)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
International Journal of Intelligent Transportation Systems Research     Hybrid Journal   (Followers: 5)
International Journal of Micro-Nano Scale Transport     Full-text available via subscription   (Followers: 2)
International Journal of Mobile Communications     Hybrid Journal   (Followers: 8)
International Journal of Ocean Systems Management     Hybrid Journal   (Followers: 3)
International Journal of Physical Distribution & Logistics Management     Hybrid Journal   (Followers: 8)
International Journal of Services Technology and Management     Hybrid Journal   (Followers: 1)
International Journal of Sustainable Transportation     Hybrid Journal   (Followers: 6)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 16)
International Journal of Transportation Science and Technology     Full-text available via subscription   (Followers: 5)
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: 11)
Journal of Modern Transportation     Full-text available via subscription   (Followers: 1)
Journal of Navigation     Hybrid Journal   (Followers: 90)
Journal of Sport & Social Issues     Hybrid Journal   (Followers: 9)
Journal of Sustainable Mobility     Full-text available via subscription  
Journal of the Transportation Research Forum     Open Access   (Followers: 4)
Journal of Traffic and Transportation Engineering (English Edition)     Open Access  
Journal of Transport & Health     Hybrid Journal   (Followers: 3)
Journal of Transport and Land Use     Open Access   (Followers: 13)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 6)
Journal of Transport Geography     Hybrid Journal   (Followers: 17)
Journal of Transport History     Full-text available via subscription   (Followers: 11)
Journal of Transport Literature     Open Access  
Journal of Transportation Safety & Security     Hybrid Journal   (Followers: 9)
Journal of Transportation Security     Hybrid Journal   (Followers: 3)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 15)
Journal of Transportation Technologies     Open Access   (Followers: 11)
Journal of Waterway Port Coastal and Ocean Engineering     Full-text available via subscription   (Followers: 7)
Les Dossiers du Grihl     Open Access  
Logistique & Management     Full-text available via subscription  
Mechatronics, Electrical Power, and Vehicular Technology     Open Access   (Followers: 1)
Mobility in History     Full-text available via subscription  
Modern Transportation     Open Access   (Followers: 2)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
Open Journal of Safety Science and Technology     Open Access   (Followers: 5)
Pervasive and Mobile Computing     Hybrid Journal   (Followers: 9)
Proceedings of the Institution of Mechanical Engineers Part F: Journal of Rail and Rapid Transit     Hybrid Journal   (Followers: 7)
PS: Political Science & Politics     Full-text available via subscription   (Followers: 24)
Public Transport     Hybrid Journal   (Followers: 10)
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: 3)
Synthesis Lectures on Mobile and Pervasive Computing     Full-text available via subscription   (Followers: 2)
Tire Science and Technology     Full-text available via subscription   (Followers: 1)
Transactions on Transport Sciences     Open Access   (Followers: 4)
Transport     Hybrid Journal   (Followers: 8)
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: 7)
Transportation     Hybrid Journal   (Followers: 20)
Transportation Geotechnics     Full-text available via subscription  
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 6)
Transportation Journal     Full-text available via subscription   (Followers: 5)
Transportation Letters : The International Journal of Transportation Research     Hybrid Journal  
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 26)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 24)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 16)
Transportation Research Procedia     Open Access  
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 32)
Transportation Science     Full-text available via subscription   (Followers: 14)
TRANSPORTES     Open Access   (Followers: 2)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 1)
Transportmetrica B : Transport Dynamics     Hybrid Journal  
Travel Behaviour and Society     Full-text available via subscription   (Followers: 1)
Travel Medicine and Infectious Disease     Hybrid Journal   (Followers: 1)
Urban, Planning and Transport Research     Open Access   (Followers: 3)
Vehicular Communications     Full-text available via subscription  
World Review of Intermodal Transportation Research     Hybrid Journal   (Followers: 3)
Транспортні системи та технології перевезень     Open Access  
Journal Cover   Transportation Research Part B: Methodological
  [SJR: 3.306]   [H-I: 70]   [24 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0191-2615
   Published by Elsevier Homepage  [2812 journals]
  • Mathematical programming formulations for transit network design
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Héctor Cancela , Antonio Mauttone , María E. Urquhart
      In this work, we study the transit network design problem from the perspective of mathematical programming. More precisely, we consider the problem of defining the number and itinerary of bus routes and their frequencies, for a public transportation system. In this problem, the routes should be defined in terms of a given infrastructure of streets and stops and should cover a given origin–destination demand. The solution (routes and frequencies) should be convenient for the users and the operators. We review existing mathematical programming formulations and propose a new one, paying attention to the following aspects of public transportation systems, that are identified as key elements in order to have a realistic model: (a) the interest of the users, (b) the interest of the operators, (c) the behavior of the users, and (d) constraints regarding transfer, infrastructure and bus capacity. First, we discuss the formulations existing on the literature, in terms of the aspects mentioned above. Second, we propose a mixed integer linear programming (MILP) formulation, that incorporates the waiting time and the existence of multiple lines in the behavior of the users. We validate the proposed formulation using several cases, including a real one. Also, we compare the obtained results against results from the existing literature. In order to include transfer, infrastructure and bus capacity constraints, we propose an extension to the formulation and we discuss its impact in the structure of the model, based on concepts of bi-level mathematical programming. The mathematical formulations developed contribute towards a more realistic modeling effort, taking into account important aspects of the real system which were not included in previous proposals in the literature.


      PubDate: 2015-05-22T02:00:07Z
       
  • Editorial Board
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77




      PubDate: 2015-05-22T02:00:07Z
       
  • Point queue models: A unified approach
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Wen-Long Jin
      In transportation and other types of facilities, various queues arise when the demands of service are higher than the supplies, and many point and fluid queue models have been proposed to study such queueing systems. However, there has been no unified approach to deriving such models, analyzing their relationships and properties, and extending them for networks. In this paper, we derive point queue models as limits of two link-based queueing model: the link transmission model and a link queue model. With two definitions for demand and supply of a point queue, we present four point queue models, four approximate models, and their discrete versions. We discuss the properties of these models, including equivalence, well-definedness, smoothness, and queue spillback, both analytically and with numerical examples. We then analytically solve Vickrey’s point queue model and stationary states in various models. We demonstrate that all existing point and fluid queue models in the literature are special cases of those derived from the link-based queueing models. Such a unified approach leads to systematic methods for studying the queueing process at a point facility and will also be helpful for studies on stochastic queues as well as networks of queues.


      PubDate: 2015-05-22T02:00:07Z
       
  • Real-time high-speed train rescheduling in case of a complete blockage
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Shuguang Zhan , Leo G. Kroon , Lucas P. Veelenturf , Joris C. Wagenaar
      This paper focuses on real-time rescheduling of railway traffic on a high speed railway line in case of a complete blockage of the railway infrastructure. Due to the disruption, all tracks in a railway segment are out of order for a certain period of time. In the situation that we consider, trains that are blocked by the disruption do not return to their origin by taking over train services in the opposite direction, but wait inside the stations until the disruption is over. Thus the main decisions to be taken are the following: in which stations do trains have to wait, in which order do they have to leave when the disruption is over, and which trains have to be canceled? A Mixed Integer Programming model is formulated to minimize the total weighted train delay and the number of canceled trains, while adhering to headway and station capacity constraints. Most instances can be solved in a single optimization run, but for the most complex instances we propose a two-stage optimization approach to improve the computational efficiency. The model is tested on real-world instances of the Beijing–Shanghai high speed railway line. The results show that the model is promising for reducing the effect of a disruption on passenger service, especially in comparison with a heuristic method used in practice.


      PubDate: 2015-05-22T02:00:07Z
       
  • Editorial Board
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75




      PubDate: 2015-05-22T02:00:07Z
       
  • Systematic bias in transport model calibration arising from the
           variability of linear data projection
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Wai Wong , S.C. Wong
      In transportation and traffic planning studies, accurate traffic data are required for reliable model calibration to accurately predict transportation system performance and ensure better traffic planning. However, it is impractical to gather data from an entire population for such estimations because the widely used loop detectors and other more advanced wireless sensors may be limited by various factors. Thus, making data inferences based on smaller populations is generally inevitable. Linear data projection is a commonly and intuitively adopted method for inferring population traffic characteristics. It projects a sample of observable traffic quantities such as traffic count based on a set of scaling factors. However, scaling factors are subject to different types of variability such as spatial variability. Models calibrated based on linearly projected data that do not account for variability may introduce a systematic bias into their parameters. Such a bias is surprisingly often ignored. This paper reveals the existence of a systematic bias in model calibration caused by variability in the linear data projection. A generalized multivariate polynomial model is applied to examine the effect of this variability on model parameters. Adjustment factors are derived and methods are proposed for detecting and removing the embedded systematic bias. A simulation is used to demonstrate the effectiveness of the proposed method. To illustrate the applicability of the method, case studies are conducted using real-world global positioning system data obtained from taxis. These data calibrate the Macroscopic Bureau of Public Road function for six 1×1km regions in Hong Kong.


      PubDate: 2015-05-22T02:00:07Z
       
  • A time-dependent freight tour synthesis model
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Iván Sánchez-Díaz , José Holguín-Veras , Xuegang (Jeff) Ban
      This paper introduces a model of urban freight demand that seeks to estimate tour flows from secondary data sources e.g., traffic counts, to bypass the need for expensive surveys. The model discussed in this paper, referred as Freight Tour Synthesis (FTS), enhances current techniques by incorporating the time-dependent tour-based behavior of freight vehicles, and the decision maker’s (e.g., metropolitan planning agency planner) preferences for different sources of information. The model, based on entropy maximization theory, estimates the most likely set of tour flows, given a set of freight trip generation estimates, a set of traffic counts per time interval, and total freight transportation cost in the network. The type of inputs used allows the assessment of changes in infrastructure, policy and land use. The ability of the model to replicate actual values is assessed using the Denver Region (CO) as a case study.


      PubDate: 2015-05-22T02:00:07Z
       
  • Applying variational theory to travel time estimation on urban arterials
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Etienne Hans , Nicolas Chiabaut , Ludovic Leclercq
      The Variational Theory (VT) expresses the LWR model as a least cost path problem. Recent researches have shown that this problem can be simply applied on a graph with a minimal number of nodes and edges when the fundamental diagram is triangular (sufficient variational graph – SVG). Such a graph accounts for traffic signal settings on an urban arterial and leads to mean traffic states for the total arterial in free-flow or congested stationary conditions. The Macroscopic Fundamental Diagram (MFD) can then be directly estimated. In this paper, we extend this method to provide the complete distribution of deterministic travel times observed on an arterial. First, we will show how to obtain a tight estimation of the arterial capacity by properly identifying the most constraining part of the SVG. Then, we will show that a modified version of the SVG allows the exact calculation of the cumulative count curves at the entry and exit of an arterial. It is finally possible to derive the full travel time distributions for any dynamic conditions.
      Graphical abstract image

      PubDate: 2015-05-22T02:00:07Z
       
  • Urban transportation emissions mitigation: Coupling high-resolution
           vehicular emissions and traffic models for traffic signal optimization
    • Abstract: Publication date: Available online 4 May 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Carolina Osorio , Kanchana Nanduri
      This paper proposes a methodology that allows high-resolution traffic and emissions models, known as microscopic simulation models, to be efficiently used to address transportation optimization problems that account for complex environmental metrics. The methodology consists of a metamodel simulation-based optimization (SO) approach. The metamodel combines traffic and emissions information from high-resolution microscopic simulators with information from lower-resolution analytical macroscopic models. This paper formulates and uses an analytical and differentiable macroscopic approximation of the non-differentiable simulation-based microscopic emissions model. A differentiable macroscopic traffic model is also used. This paper shows that the analytical structural information provided by macroscopic analytical emissions models can contribute, despite their lower-resolution, to enhance the computational efficiency of algorithms that embed higher-resolution inefficient emissions models. The proposed algorithm is computationally efficient, i.e., it can identify points with improved performance within few simulation runs. More generally, the results of this paper highlight the added value of embedding analytical structural information within SO algorithms to address complex SO problems. A traffic signal control case study is carried out. The proposed metamodel identifies signal plans that improve travel time and various emissions metrics. We present the corresponding monetary savings that can be achieved. This optimization framework enables practitioners to use high-resolution microscopic traffic and emissions models to systematically design transportation schemes that account directly, in the design process, for environmental metrics. Hence, the use of such high-resolution models is no longer limited to the environmental evaluation of a small set of predetermined schemes. The tight computational budgets used in this paper show that such complex problems can be addressed in a computationally efficient manner.


      PubDate: 2015-05-22T02:00:07Z
       
  • Estimating exponential scheduling preferences
    • Abstract: Publication date: Available online 13 May 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Katrine Hjorth , Maria Börjesson , Leonid Engelson , Mogens Fosgerau
      Different assumptions about travelers’ scheduling preferences yield different measures of the cost of travel time variability. Only few forms of scheduling preferences provide non-trivial measures which are additive over links in transport networks where link travel times are arbitrarily distributed independent random variables: Assuming smooth preferences, this holds only for specifications with a constant marginal utility of time at the origin and an exponential or affine marginal utility of time at the destination. We apply a generalized version of this model to stated preference data of car drivers’ route and mode choice under uncertain travel times. Our analysis exposes some important methodological issues related to complex non-linear scheduling models: One issue is identifying the point in time where the marginal utility of being at the destination becomes larger than the marginal utility of being at the origin. Another issue is that models with the exponential marginal utility formulation suffer from empirical identification problems. Though our results are not decisive, they partly support the constant-affine specification, in which the value of travel time variability is proportional to the variance of travel time.


      PubDate: 2015-05-22T02:00:07Z
       
  • Train scheduling for minimizing passenger waiting time with time-dependent
           demand and skip-stop patterns: Nonlinear integer programming models with
           linear constraints
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): Huimin Niu , Xuesong Zhou , Ruhu Gao
      This paper focuses on how to minimize the total passenger waiting time at stations by computing and adjusting train timetables for a rail corridor with given time-varying origin-to-destination passenger demand matrices. Given predetermined train skip-stop patterns, a unified quadratic integer programming model with linear constraints is developed to jointly synchronize effective passenger loading time windows and train arrival and departure times at each station. A set of quadratic and quasi-quadratic objective functions are proposed to precisely formulate the total waiting time under both minute-dependent demand and hour-dependent demand volumes from different origin–destination pairs. We construct mathematically rigorous and algorithmically tractable nonlinear mixed integer programming models for both real-time scheduling and medium-term planning applications. The proposed models are implemented using general purpose high-level optimization solvers, and the model effectiveness is further examined through numerical experiments of real-world rail train timetabling test cases.


      PubDate: 2015-05-22T02:00:07Z
       
  • Repeatability & reproducibility: Implications of using GPS data
           for freight activity chains
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): Johan W. Joubert , Sumarie Meintjes
      As transport modellers we are interested in capturing the behaviour of freight vehicles that includes the locations at which vehicles perform their activities, the duration of activities, how often these locations are visited, and the sequence in which they are visited. With disaggregated freight behaviour data being scarce, transport modellers have identified vehicle tracking and fleet management companies as ideal third party sources for GPS travel data. GPS data does not provide us with behavioural information, but allows us to infer and extract behavioural knowledge using a variety of processing techniques. Many researchers remain sceptical as specific human intervention, referred to as ‘expert knowledge’, is often required during the processing phase: each GPS data set has unique characteristics and requires unique processing techniques and validation to extract the necessary behavioural information. Although much of the GPS data processing is automated through algorithms, human scrutiny is required to decide what algorithmic parameters as considered ‘best’, or at least ‘good’. In this paper we investigate the repeatability and reproducibility (R&R) of a method that entails variable human intervention in processing GPS data. More specifically, the judgement made by an observer with domain expertise on what clustering parameters applied to GPS data best identify the facilities where commercial vehicles perform their activities. By studying repeatability we want to answer the question ‘if the same expert analyses the GPS data more than once, how similar are the outcomes?’, and with reproducibility we want to answer the question ‘if different experts analyse the same GPS data, how similar are their outcomes?’ We follow two approaches to quantify the R&R and conclude in both cases that the measurement system is accurate. The use of GPS data and the associated expert judgements can hence be applied with confidence in freight transport models.


      PubDate: 2015-05-22T02:00:07Z
       
  • A piecewise-constant congestion taxing policy for repeated routing games
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Farhad Farokhi , Karl H. Johansson
      In this paper, we consider repeated routing games with piecewise-constant congestion taxing in which a central planner sets and announces the congestion taxes for fixed windows of time in advance. Specifically, congestion taxes are calculated using marginal congestion pricing based on the flow of the vehicles on each road prior to the beginning of the taxing window (and, hence, there is a time-varying delay in setting the congestion taxes). We motivate the piecewise-constant taxing policy by that users or drivers may dislike fast-changing prices and that they also prefer prior knowledge of the prices. We prove for this model that the multiplicative update rule and the discretized replicator dynamics converge to a socially optimal flow when using vanishing step sizes. Considering that the algorithm cannot adapt itself to a changing environment when using vanishing step sizes, we propose adopting constant step sizes in this case. Then, however, we can only prove the convergence of the dynamics to a neighborhood of the socially optimal flow (with the size of the neighbourhood being of the order of the selected step size). The results are illustrated on a nonlinear version of Pigou’s famous routing game.


      PubDate: 2015-05-22T02:00:07Z
       
  • A joint bottom-up solution methodology for system-level pavement
           rehabilitation and reconstruction
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Jinwoo Lee , Samer Madanat
      We present a methodology for the joint optimization of rehabilitation and reconstruction activities for heterogeneous pavement systems under multiple budget constraints. The proposed bottom-up approach adopts an augmented condition state to account for the history-dependent properties of pavement deterioration, and solves for steady-state policies for an infinite horizon. Genetic algorithms (GAs) are implemented in the system-level optimization based on segment-specific optimization results. The complexity of the proposed algorithm is polynomial in the size of the system and the policy-related parameters. We provide graphical presentations of the optimal solutions for various budget situations. As a case study, a subset of California’s highway system is analyzed. The case study results demonstrate the economic benefit of a combined rehabilitation and reconstruction budget compared to separate budgets.


      PubDate: 2015-05-22T02:00:07Z
       
  • Analysis of real-time control strategies in a corridor with multiple bus
           services
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Daniel Hernández , Juan Carlos Muñoz , Ricardo Giesen , Felipe Delgado
      Control strategies have been widely used in the literature to counteract the effects of bus bunching in passenger‘s waiting times and its variability. These strategies have only been studied for the case of a single bus line in a corridor. However, in many real cases this assumption does not hold. Indeed, there are many transit corridors with multiple bus lines interacting, and this interaction affects the efficiency of the implemented control mechanism. This work develops an optimization model capable of executing a control scheme based on holding strategy for a corridor with multiple bus lines. We analyzed the benefits in the level of service of the public transport system when considering a central operator who wants to maximize the level of service for users of all the bus lines, versus scenarios where each bus line operates independently. A simulation was carried out considering two medium frequency bus lines that serve a set of stops and where these two bus lines coexist in a given subset of stops. In the simulation we compared the existence of a central operator, using the optimization model we developed, against the independent operation of each line. In the simulations the central operator showed a greater reduction in the overall waiting time of the passengers of 55% compared to a no control scenario. It also provided a balanced load of the buses along the corridor, and a lower variability of the bus headways in the subset of stops where the lines coexist, thus obtaining better reliability for all types of passengers present in the public transport system.


      PubDate: 2015-05-22T02:00:07Z
       
  • A two-stage robustness approach to evacuation planning with buses
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Marc Goerigk , Kaouthar Deghdak , Vincent T’Kindt
      We consider the problem of scheduling a bus fleet to evacuate persons from an endangered region. As most of the planning data is subject to uncertainty, we develop a two-stage bicriteria robust formulation, which considers both the evacuation time, and the vulnerability of the schedule to changing evacuation circumstances. As the resulting integer program is too large to be solved directly using an off-the-shelf solver, we develop a scenario-generation algorithm which iteratively adds new scenarios to the incumbent subproblem being solved. Computational experiments show that this approach is fast enough to solve a realistic instance corresponding to an evacuation case within the city of Kaiserslautern (Germany).


      PubDate: 2015-05-22T02:00:07Z
       
  • A rolling horizon algorithm for auto-carrier transportation
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): Jean-François Cordeau , Mauro Dell’Amico , Simone Falavigna , Manuel Iori
      This paper introduces a rolling horizon algorithm to plan the delivery of vehicles to automotive dealers by a heterogeneous fleet of auto-carriers. The problem consists in scheduling the deliveries over a multiple-day planning horizon during which requests for transportation arrive dynamically. In addition, the routing of the auto-carriers must take into account constraints related to the loading of the vehicles on the carriers. The objective is to minimize the sum of traveled distances, fixed costs for auto-carrier operation, service costs, and penalties for late deliveries. The problem is solved by a heuristic that first selects the vehicles to be delivered in the next few days and then optimizes the deliveries by an iterated local search procedure. A branch-and-bound search is used to check the feasibility of the loading. To handle the dynamic nature of the problem, the complete algorithm is applied repeatedly in a rolling horizon framework. Computational results on data from a major European logistics service provider show that the heuristic is fast and yields significant improvements compared to the sequential solution of independent daily problems.


      PubDate: 2015-05-22T02:00:07Z
       
  • The economic speed of an oceangoing vessel in a dynamic setting
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): Evangelos F. Magirou , Harilaos N. Psaraftis , Theodore Bouritas
      The optimal (economic) speed of oceangoing vessels has become of increased importance due to the combined effect of low freight rates and volatile bunker prices. We examine the problem for vessels operating in the spot market in a tramp mode. In the case of known freight rates between origin destination combinations, a dynamic programming formulation can be applied to determine both the optimal speed and the optimal voyage sequence. Analogous results are derived for random freight rates of known distributions. In the case of independent rates the economic speed depends on fuel price and the expected freight rate, but is independent of the revenue of the particular voyage. For freight rates that depend on a state of the market Markovian random variable, economic speed depends on the market state as well, with increased speed corresponding to good states of the market. The dynamic programming equations in our models differ from those of Markovian decision processes so we develop modifications of standard solution methods, and apply them to small examples.


      PubDate: 2015-05-22T02:00:07Z
       
  • Nonlinear multivariate time–space threshold vector error correction
           model for short term traffic state prediction
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): Tao Ma , Zhou Zhou , Baher Abdulhai
      We propose Time–Space Threshold Vector Error Correction (TS-TVEC) model for short term (hourly) traffic state prediction. The theory and method of cointegration with error correction mechanism is employed in the general design of the new statistical model TS-TVEC. An inherent connection between mathematical form of error correction model and traffic flow theory is revealed through the transformation of the well-known Fundamental Traffic Diagrams. A threshold regime switching framework is implemented to overcome any unknown structural changes in traffic time series. Spatial cross correlated information is incorporated with a piecewise linear vector error correction model. A Neural Network model is also constructed in parallel to comparatively test the effectiveness and robustness of the new statistical model. Our empirical study shows that the TS-TVEC model is an effective tool that is capable of modeling the complexity of stochastic traffic flow processes and potentially applicable to real time traffic state prediction.


      PubDate: 2015-05-22T02:00:07Z
       
  • Inference on mode preferences, vehicle purchases, and the energy paradox
           using a Bayesian structural choice model
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): Ricardo A. Daziano
      Discrete choice modeling is experiencing a reemergence of research interest in the inclusion of latent variables as explanatory variables of consumer behavior. There are several reasons that motivate the integration of latent attributes, including better-informed modeling of random consumer heterogeneity and treatment of endogeneity. However, current work still is at an early stage and multiple simplifying assumptions are usually imposed. For instance, most previous applications assume all of the following: independence of taste shocks and of latent attributes, exclusion restrictions, linearity of the effect of the latent attributes on the utility function, continuous manifest variables, and an a priori bound for the number of latent constructs. We derive and apply a structural choice model with a multinomial probit kernel and discrete effect indicators to analyze continuous latent segments of travel behavior, including inference on the energy paradox. Our estimator allows for interaction and simultaneity among the latent attributes, residual correlation, nonlinear effects on the utility function, flexible substitution patterns, and temporal correlation within responses of the same individual. Statistical properties of the Bayes estimator that we propose are exact and are not affected by the number of latent attributes.


      PubDate: 2015-05-22T02:00:07Z
       
  • Empirical flow-density and speed-spacing relationships: Evidence of
           vehicle length dependency
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Benjamin Coifman
      Traffic flow theory has come to a point where conventional, fixed time averaged data are limiting our insight into critical behavior both at the macroscopic and microscopic scales. This paper develops a methodology to measure relationships of density and vehicle spacing on freeways. These relationships are central to most traffic flow theories but have historically been difficult to measure empirically. The work leads to macroscopic flow-density and microscopic speed-spacing relationships in the congested regime derived entirely from dual loop detector data and then verified against the NGSIM data set. The methodology eliminates the need to seek out stationary conditions and yields clean relationships that do not depend on prior assumptions of the curve shape before fitting the data. Upon review of the clean empirical relationships a key finding of this work is the fact that many of the critical parameters of the macroscopic flow-density and microscopic speed-spacing relationships depend on vehicle length, e.g., upstream moving waves should travel through long vehicles faster than through short vehicles. Thus, the commonly used assumption of a homogeneous vehicle fleet likely obscures these important phenomena. More broadly, if waves travel faster or slower depending on the length of the vehicles through which the waves pass, then the way traffic is modeled should be updated to explicitly account for inhomogeneous vehicle lengths.


      PubDate: 2015-05-22T02:00:07Z
       
  • From behavioral psychology to acceleration modeling: Calibration,
           validation, and exploration of drivers’ cognitive and safety
           parameters in a risk-taking environment
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Samer H. Hamdar , Hani S. Mahmassani , Martin Treiber
      We investigate a utility-based approach for driver car-following behavioral modeling while analyzing different aspects of the model characteristics especially in terms of capturing different fundamental diagram regions and safety proxy indices. The adopted model came from an elementary thought where drivers associate subjective utilities for accelerations (i.e. gain in travel times) and subjective dis-utilities for decelerations (i.e. loss in travel time) with a perceived probability of being involved in rear-end collision crashes. Following the testing of the model general structure, the authors translate the corresponding behavioral psychology theory – prospect theory – into an efficient microscopic traffic modeling with more elaborate stochastic characteristics considered in a risk-taking environment. After model formulation, we explore different model disaggregate and aggregate characteristics making sure that fidelity is kept in terms of equilibrium properties. Significant effort is then dedicated to calibrating and validating the model using microscopic trajectory data. A modified genetic algorithm is adopted for this purpose while focusing on capturing inter-driver heterogeneity for each of the parameters. Using the calibration exercise as a starting point, simulation sensitivity analysis is performed to reproduce different fundamental diagram regions and to explore rear-end collisions related properties. In terms of fundamental diagram regions, the model in hand is able to capture traffic breakdowns and different instabilities in the congested region represented by flow-density data points scattering. In terms of incident related measures, the effect of heterogeneity in both psychological factors and execution/perception errors on the accidents number and their distribution is studied. Through sensitivity analysis, correlations between the crash-penalty, the negative coefficient associated with losses in speed, the positive coefficient associated with gains in speed, the driver’s uncertainty, the anticipation time and the reaction time are retrieved. The formulated model offers a better understanding of driving behavior, particularly under extreme/incident conditions.


      PubDate: 2015-05-22T02:00:07Z
       
  • Editorial Board
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76




      PubDate: 2015-05-22T02:00:07Z
       
  • Continuum signalized junction model for dynamic traffic networks: Offset,
           spillback, and multiple signal phases
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Ke Han , Vikash V. Gayah
      This paper extends the continuum signalized intersection model exhaustively studied in Han et al. (2014) to more accurately account for three realistic complications: signal offsets, queue spillbacks, and complex signal phasing schemes. The model extensions are derived theoretically based on signal cycle, green split, and offset, and are shown to approximate well traffic operations at signalized intersections treated using the traditional (and more realistic) on-and-off model. We propose a generalized continuum signal model, which explicitly handles complex vehicle spillback patterns on signalized networks with provable error estimates. Under mild conditions, the errors are small and bounded by fixed values that do not grow with time. Overall, this represents a significant improvement over the original continuum model, which had errors that grew quickly with time in the presence of any queue spillbacks and for which errors were not explicitly derived for different offset cases. Thus, the new model is able to more accurately approximate traffic dynamics in large networks with multiple signals under more realistic conditions. We also qualitatively describe how this new model can be applied to several realistic intersection configurations that might be encountered in typical urban networks. These include intersections with multiple entry and exit links, complex signal phasing, all-red times, and the presence of dedicated turning lanes. Numerical tests of the models show remarkable consistency with the on-and-off model, as expected from the theory, with the added benefit of significant computational savings and higher signal control resolution when using the continuum model.


      PubDate: 2015-05-22T02:00:07Z
       
  • Leveraging social networks for efficient hurricane evacuation
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Manini Madireddy , Soundar Kumara , D.J. Medeiros , Venky N. Shankar
      One of the important factors affecting evacuation performance is the departure time choices made by evacuees. Simultaneous departures of evacuees can lead to overloading of road networks causing congestion. We are especially interested in cases when evacuees subject to little or no risk of exposure evacuate along with evacuees subject to higher risk of threat (also known as shadow evacuation). One of the reasons for correlated evacuee departures is higher perceived risk of threat spread through social contacts. In this work, we study an evacuation scenario consisting of a high risk region and a surrounding low risk area. We propose a probabilistic evacuee departure time model incorporating both evacuee individual characteristics and the underlying evacuee social network. We find that the performance of an evacuation process can be improved by forcing a small subset of evacuees (inhibitors) in the low risk area to delay their departure. The performance of an evacuation is measured by both average travel time of the population and total evacuation time of the high risk evacuees. We derive closed form expressions for average travel time for ER random network. A detailed experimental analysis of various inhibitor selection strategies and their effectiveness on different social network topologies and risk distribution is performed. Results indicate that significant improvement in evacuation performance can be achieved in scenarios where evacuee social networks have short average path lengths and topologically influential evacuees do not belong to the high risk regions. Additionally, communities with stronger ties improve evacuation performance.


      PubDate: 2015-05-22T02:00:07Z
       
  • Continuous approximation models for mixed load school bus routing
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): William A. Ellegood , James F. Campbell , Jeremy North
      School bus routing is a complex and expensive transportation problem for many public school districts. Typical school bus routes serve a single school, but mixed load school bus routes carry students for more than one school at the same time. A mixed load policy reduces the number of stops and distance to pick up and drop off children, but it can increase travel distance by visiting multiple schools. This paper provides a general strategic analysis using continuous approximation models to assess the conditions under which mixed loading is likely to be beneficial. We also present a case study for a semi-rural Missouri school district to illustrate the application of the models in practice. Results show that mixed load routing is more beneficial for larger districts, when a large percentage of bus stops are shared by students of different schools, and when schools are closer together.


      PubDate: 2015-05-22T02:00:07Z
       
  • Stochastic user equilibrium with equilibrated choice sets: Part I –
           Model formulations under alternative distributions and restrictions
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): David Paul Watling , Thomas Kjær Rasmussen , Carlo Giacomo Prato , Otto Anker Nielsen
      The aim of this paper is to remove the known limitations of Deterministic and Stochastic User Equilibrium (DUE and SUE), namely that only routes with the minimum cost are used in DUE, and that all permitted routes are used in SUE regardless of their costs. We achieve this by combining the advantages of the two principles, namely the definition of unused routes in DUE and of mis-perception in SUE, such that the resulting choice sets of used routes are equilibrated. Two model families are formulated to address this issue: the first is a general version of SUE permitting bounded and discrete error distributions; the second is a Restricted SUE model with an additional constraint that must be satisfied for unused paths. The overall advantage of these model families consists in their ability to combine the unused routes with the use of random utility models for used routes, without the need to pre-specify the choice set. We present model specifications within these families, show illustrative examples, evaluate their relative merits, and identify key directions for further research.


      PubDate: 2015-05-22T02:00:07Z
       
  • Stochastic user equilibrium with equilibrated choice sets: Part II –
           Solving the restricted SUE for the logit family
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Thomas Kjær Rasmussen , David Paul Watling , Carlo Giacomo Prato , Otto Anker Nielsen
      We propose a new class of path-based solution algorithms to solve the Restricted Stochastic User Equilibrium (RSUE), as introduced in Watling et al. (2015). The class allows a flexible specification of how the choice sets are systematically grown by considering congestion effects and how the flows are allocated among routes. The specification allows adapting traditional path-based stochastic user equilibrium flow allocation methods (originally designed for pre-specified choice sets) to the generic solution algorithm. We also propose a cost transformation function and show that by using this we can, for certain Logit-type choice models, modify existing path-based Deterministic User Equilibrium solution methods to compute RSUE solutions. The transformation function also leads to a two-part relative gap measure for consistently monitoring convergence to a RSUE solution. Numerical tests are reported on two real-life cases, in which we explore convergence patterns and choice set composition and size, for alternative specifications of the RSUE model and solution algorithm.


      PubDate: 2015-05-22T02:00:07Z
       
  • The reliable hub-and-spoke design problem: Models and algorithms
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Yu An , Yu Zhang , Bo Zeng
      Hub-and-spoke structure is widely adopted in industry, especially in transportation and telecommunications applications. Although hub-and-spoke paradigm demonstrates significant advantages in improving network connectivity with less number of routes and saving operating cost, the failure of hubs and reactive disruption management could lead to substantial recovery cost to the operators. Thus, we propose a set of reliable hub-and-spoke network design models, where the selection of backup hubs and alternative routes are taken into consideration to proactively handle hub disruptions. To solve these nonlinear mixed integer formulations for reliable network design problems, Lagrangian relaxation and Branch-and-Bound methods are developed to efficiently obtain optimal solutions. Numerical experiments are conducted with respect to real data to demonstrate algorithm performance and to show that the resulting hub-and-spoke networks are more resilient to hub unavailability.


      PubDate: 2015-05-22T02:00:07Z
       
  • Route choice and traffic signal control: A study of the stability and
           instability of a new dynamical model of route choice and traffic signal
           control
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Ronghui Liu , Mike Smith
      This paper presents a novel idealised dynamical model of day to day traffic re-routeing (as traffic seeks cheaper routes) and proves a stability result for this dynamical model. (The dynamical model is based on swapping flow between paired alternative segments (these were introduced by Bar-Gera (2010)) rather than between routes.) It is shown that under certain conditions the dynamical system enters a given connected set of approximate equilibria in a finite number of days or steps. This proof allows for saturation flows which act as potentially active flow constraints. The dynamical system involving paired alternative segment swaps is then combined with a novel green-time-swapping rule; this rule swaps green-time toward more pressurised signal stages. It is shown that if (i) the delay formulae have a simple form and (ii) the “pressure” formula fits the special control policy P 0 (see Smith, 1979a,b), then the combined flow-swapping/green-time-swapping dynamical model also enters a given connected set of approximate consistent equilibria in a finite number of steps. Computational results confirm, in a simple network, the positive P 0 result and also show, on the other hand, that such good behaviour may not arise if the equi-saturation control policy is utilised. The dynamical models described here do not represent blocking back effects.


      PubDate: 2015-05-22T02:00:07Z
       
  • Impact of stop-and-go waves and lane changes on discharge rate in recovery
           flow
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Simon Oh , Hwasoo Yeo
      In an effort to uncover traffic conditions that trigger discharge rate reductions near active bottlenecks, this paper analyzed individual vehicle trajectories at a microscopic level and documented the findings. Based on an investigation of traffic flow involving diverse traffic situations, a driver’s tendency to take a significant headway after passing stop-and-go waves was identified as one of the influencing factors for discharge rate reduction. Conversely, the pattern of lane changers caused a transient increase in the discharge rate until the situation was relaxed after completing the lane-changing event. Although we observed a high flow from the incoming lane changers, the events ultimately caused adverse impacts on the traffic such that the disturbances generated stop-and-go waves. Based on this observation, we regard upstream lane changes and stop-and-go waves as the responsible factors for the decreased capacity at downstream of active bottlenecks. This empirical investigation also supports the resignation effect, the regressive effect, and the asymmetric behavioral models in differentiating acceleration and deceleration behaviors.
      Graphical abstract image

      PubDate: 2015-05-22T02:00:07Z
       
  • Container vessel fleet deployment for liner shipping with stochastic
           dependencies in shipping demand
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): ManWo Ng
      The problem of optimal container vessels deployment is one of great significance for the liner shipping industry. Although the pioneering work on this problem dates back to the early 1990s, only until recently have researchers started to acknowledge and account for the significant amount of uncertainty present in shipping demand in real world container shipping. In this paper, new analytical results are presented to further relax the input requirements for this problem. Specifically, only the mean and variance of the maximum shipping demand are required to be known. An optional symmetry assumption is shown to further reduce the feasible region and deployment cost for typical confidence levels. Moreover, unlike previous work that tends to ignore stochastic dependencies between the shipping demands on the various routes (that are known to exist in the real world), our models account for such dependencies in the most general setting to date. A salient feature of our modeling approach is that the exact dependence structure does not need to be specified, something that is hard, if not simply impossible, to determine in practice. A numerical case study is provided to illustrate the proposed models.


      PubDate: 2015-05-22T02:00:07Z
       
  • Optimal housing supply in a bid-rent equilibrium framework
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Ka Fai Ng , Hong K. Lo
      In this study, we examine how the spatial distribution of housing supply impacts people’s residential choices and developers’ profitability. By optimally providing housing supply in a region, developers attempt to maximize their profits; on the other hand, if residents were given a chance to decide on housing supply, what patterns of housing supply they would prefer in order to maximize their consumer surpluses. This paper studies the interplay between these two perspectives. A nested multinomial-logit choice structure that encapsulates the bid-rent process is used to capture residents’ location and travel choices simultaneously, and the resultant rents at different locations. To investigate the optimal housing supply for these two stakeholders, we conduct sensitivity analyzes to explore the impact of different housing supply patterns on total rental profit and total consumer surplus. Specifically, analytical results are derived for a simple linear network with two residential locations and one destination under homogeneous and heterogeneous value(s) of time. The results of the sensitivity analyzes indicate that segregation of housing supplies at different locations for different income classes is, surprisingly, a “preferred” outcome by residents under consumer surplus maximization, whereas creating housing supply shortages at convenient locations is a natural outcome under housing profit maximization. These results provide insights on revealing the differences and tradeoffs in performance between these two different perspectives, and on where land use regulations may be needed to balance these two objectives.


      PubDate: 2015-05-22T02:00:07Z
       
  • Optimization of bus stop placement for routes on uneven topography
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Avishai (Avi) Ceder , Matthew Butcher , Lingli Wang
      The improvement and expansion of public transport is an increasingly important solution to the high congestion costs and worsening environmental impacts of the car dominated transport systems seen in many cities today. The intelligent design of stop locations is one way to improve the quality of PT and thereby improve its ridership. Stop placement is a relatively complex task as it involves a trade-off between two competing goals; accessibility and operation; however this trade-off can be made explicit using an appropriate mathematical model. Many such models have been developed in the literature, however none consider the effects of uneven topography. Topography is an important but often neglected factor in the design of public transportation systems, with the potential to have a significant impact on the accessibility, operation and planning of a transit service. In this work a mathematical modelling approach to bus stop placement is developed which includes considerations of uneven topography in three ways; (1) Its effect on walking speed; (2) Its impact on the attractiveness of an access path to a transit service; and (3) Its effect on acceleration rates at stops. Because of the complexity of the model developed, a heuristic evolutionary algorithm’ is employed to approximate an optimal solution to the model. Finally, the model and solution method are applied to a case study in the Auckland CBD area in New Zealand.


      PubDate: 2015-05-22T02:00:07Z
       
  • A family of macroscopic node models
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Erik-Sander Smits , Michiel C.J. Bliemer , Adam J. Pel , Bart van Arem
      The family of macroscopic node models which comply to a set of basic requirements is presented and analysed. Such models are required in macro-, mesoscopic traffic flow models, including dynamic network loading models for dynamic traffic assignment. Based on the behaviour of drivers approaching and passing through intersections, the model family is presented. The headway and the turn delay of vehicles are key variables. Having demand and supply as input creates a natural connection to macroscopic link models. Properties like the invariance principle and the conservation of turning fractions are satisfied. The inherent non-uniqueness is analysed by providing the complete set of feasible solutions. The node models proposed by Tampère et al. (2011), Flötteröd and Rohde (2011) and Gibb (2011) are members of the family. Furthermore, two new models are added to the family. Solution methods for all family members are presented, as well as a qualitative and quantitative comparison. Finally, an outlook for the future development of empirically verified models is given.


      PubDate: 2015-05-22T02:00:07Z
       
  • Editorial Board
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74




      PubDate: 2015-05-22T02:00:07Z
       
  • Dynamics of heterogeneity in urban networks: aggregated traffic modeling
           and hierarchical control
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Mohsen Ramezani , Jack Haddad , Nikolas Geroliminis
      Real traffic data and simulation analysis reveal that for some urban networks a well-defined Macroscopic Fundamental Diagram (MFD) exists, which provides a unimodal and low-scatter relationship between the network vehicle density and outflow. Recent studies demonstrate that link density heterogeneity plays a significant role in the shape and scatter level of MFD and can cause hysteresis loops that influence the network performance. Evidently, a more homogeneous network in terms of link density can result in higher network outflow, which implies a network performance improvement. In this article, we introduce two aggregated models, region- and subregion-based MFDs, to study the dynamics of heterogeneity and how they can affect the accuracy scatter and hysteresis of a multi-subregion MFD model. We also introduce a hierarchical perimeter flow control problem by integrating the MFD heterogeneous modeling. The perimeter flow controllers operate on the border between urban regions, and manipulate the percentages of flows that transfer between the regions such that the network delay is minimized and the distribution of congestion is more homogeneous. The first level of the hierarchical control problem can be solved by a model predictive control approach, where the prediction model is the aggregated parsimonious region-based MFD and the plant (reality) is formulated by the subregion-based MFDs, which is a more detailed model. At the lower level, a feedback controller of the hierarchical structure, tries to maximize the outflow of critical regions, by increasing their homogeneity. With inputs that can be observed with existing monitoring techniques and without the need for detailed traffic state information, the proposed framework succeeds to increase network flows and decrease the hysteresis loop of the MFD. Comparison with existing perimeter controllers without considering the more advanced heterogeneity modeling of MFD highlights the importance of such approach for traffic modeling and control.


      PubDate: 2015-05-22T02:00:07Z
       
  • Dynamic ridesharing: Is there a role for dedicated drivers?
    • Abstract: Publication date: Available online 9 April 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Alan Lee , Martin Savelsbergh
      Growing congestion is a problem faced by cities around the world. Traditional solutions considered include new capital works to increase network capacity and expanding public transport offerings to make public transport more attractive. Dynamic ridesharing is a recent alternative in which people with similar travel plans are matched and travel together. Dynamic ridesharing requires no new network infrastructure and offers more convenience than public transport. The (long-term) success of ridesharing schemes, however, depends on their ability to attract a large number of users. We investigate the benefits, complexities, and costs of employing a small number of dedicated drivers to serve riders who would otherwise remain unmatched. An extensive computational study demonstrates the potential benefits of dedicated drivers and identifies environments in which dedicated drivers are most useful.


      PubDate: 2015-05-22T02:00:07Z
       
  • A general approach for controlling vehicle en-route diversions in dynamic
           vehicle routing problems
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): Francesco Ferrucci , Stefan Bock
      Previous research has shown that vehicle en-route diversion can improve the efficiency of dynamic vehicle routing processes. However, an uncontrolled utilization of en-route diversions may increase demands on drivers and cause distraction. This is likely to result in more accidents or reduced productivity which generates additional costs. Since the benefits to the solution quality make a prohibition of en-route diversions unattractive, we propose a general penalty cost based approach for controlling diversions. In contrast to known approaches that allow all diversions, the proposed approach also considers negative application-dependent consequences of diversions on drivers. The approach limits diversions to those which improve the solution quality above a customizable and application-dependent threshold that estimates their negative consequences. We evaluate the proposed general approach by applying it on an exemplary basis to recent deterministic and pro-active real-time routing approaches. Computational experiments show the impact of different penalty cost values on the resulting number of diversions as well as on the attained solution quality. Based on these results, we derive reasonable application-dependent penalty cost values for considering both the contradicting aims of quick request delivery and reducing diversions to a desired extent.


      PubDate: 2015-05-22T02:00:07Z
       
  • An exact algorithm for the mean–standard deviation shortest path
           problem
    • Abstract: Publication date: Available online 21 April 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Alireza Khani , Stephen D. Boyles
      This paper studies the reliable path problem in the form of minimizing the sum of mean and standard deviation of path travel time. For the case of independent link travel times, we show that the problem can be solved exactly by repeatedly solving a subproblem minimizing the sum of mean and variance of path travel time. The latter is an additive shortest path problem, and can be solved using a standard labeling algorithm. While these subproblems are similar in form to those obtained from Lagrangian relaxation, this formulation admits proof of finite convergence to the optimal solution. An iterative labeling algorithm is developed that solves the non-additive reliable path problem from a single origin to all destinations. Moreover, a labeling technique is employed to further reduce the computational time of the proposed algorithm by partially updating the network in each iteration. As an alternative, a bisection-type search algorithm is developed that solves the problem for the single-origin and single-destination case. Numerical tests are presented, indicating that the proposed algorithm outperform others recently proposed in the literature: unlike Lagrangian relaxation, two of the proposed algorithms find solutions exactly, and the computation time is an order of magnitude faster than outer approximation methods.


      PubDate: 2015-05-22T02:00:07Z
       
  • Distance-dependent congestion pricing for downtown zones
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Carlos F. Daganzo , Lewis J. Lehe
      A growing literature exploits macroscopic theories of traffic to model congestion pricing policies in downtown zones. This study introduces trip length heterogeneity into this analysis and proposes a usage-based, time-varying congestion toll that alleviates congestion while prioritizing shorter trips. Unlike conventional trip-based tolls the scheme is intended to align the fees paid by drivers with the actual congestion damage they do, and to increase the toll’s benefits as a result. The scheme is intended to maximize the number of people that finish their trips close to their desired times. The usage-based toll is compared to a traditional, trip-based toll which neglects trip length. It is found that, like trip-based tolls, properly designed usage-based tolls alleviate congestion. But they reduce schedule delay more than trip-based tolls and do so with much smaller user fees. As a result usage-based tolls leave most of those who pay with a large welfare gain. This may increase the tolls’ political acceptability.


      PubDate: 2015-05-22T02:00:07Z
       
  • A nested recursive logit model for route choice analysis
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Tien Mai , Mogens Fosgerau , Emma Frejinger
      We propose a route choice model that relaxes the independence from irrelevant alternatives property of the logit model by allowing scale parameters to be link specific. Similar to the recursive logit (RL) model proposed by Fosgerau et al. (2013), the choice of path is modeled as a sequence of link choices and the model does not require any sampling of choice sets. Furthermore, the model can be consistently estimated and efficiently used for prediction. A key challenge lies in the computation of the value functions, i.e. the expected maximum utility from any position in the network to a destination. The value functions are the solution to a system of non-linear equations. We propose an iterative method with dynamic accuracy that allows to efficiently solve these systems. We report estimation results and a cross-validation study for a real network. The results show that the NRL model yields sensible parameter estimates and the fit is significantly better than the RL model. Moreover, the NRL model outperforms the RL model in terms of prediction.


      PubDate: 2015-05-22T02:00:07Z
       
  • Optimal layout of transshipment facility locations on an infinite
           homogeneous plane
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Weijun Xie , Yanfeng Ouyang
      This paper studies optimal spatial layout of transshipment facilities and the corresponding service regions on an infinite homogeneous plane R 2 that minimize the total cost for facility set-up, outbound delivery and inbound replenishment transportation. The problem has strong implications in the context of freight logistics and transit system design. This paper first focuses on a Euclidean plane and shows that a tight upper bound can be achieved by a type of elongated cyclic hexagons, while a cost lower bound based on relaxation and idealization is also obtained. The gap between the analytical upper and lower bounds is within 0.3%. This paper then shows that a similar elongated non-cyclic hexagon shape, with proper orientation, is actually optimal for service regions on a rectilinear metric plane. Numerical experiments are conducted to verify the analytical findings and to draw further insights.


      PubDate: 2015-05-22T02:00:07Z
       
  • The split-demand one-commodity pickup-and-delivery travelling salesman
           problem
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Juan-José Salazar-González , Beatriz Santos-Hernández
      This paper introduces a new vehicle routing problem transferring one commodity between customers with a capacitated vehicle that can visit a customer more than once, although a maximum number of visits must be respected. It generalizes the capacitated vehicle routing problem with split demands and some other variants recently addressed in the literature. We model the problem with a single commodity flow formulation and design a branch-and-cut approach to solve it. We make use of Benders Decomposition to project out the flow variables from the formulation. Inequalities to strengthen the linear programming relaxation are also presented and separated within the approach. Extensive computational results illustrate the performance of the approach on benchmark instances from the literature.


      PubDate: 2015-05-22T02:00:07Z
       
  • An anisotropic continuum model considering bi-directional information
           impact
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Liang Zheng , Peter J. Jin , Helai Huang
      In traffic flow with naturalistic driving only, stimulus information pre-dominantly comes from the preceding vehicles with drivers occasionally responding to the following vehicles through the inspection of rear-view mirrors. Such one-sided information propagation may potentially be altered in future connected vehicle environment. This brings new motivations of modeling vehicle dynamics under bi-directional information propagation. In this study, stemming from microscopic bi-directional car-following models, a continuum traffic flow model is put forward that incorporates the bi-directional information impact macroscopically but can still preserve the anisotropic characteristics of traffic flow and avoid non-physical phenomenon such as wrong-way travels. We then analyze the properties of the continuum model and respectively illustrate the condition that guarantees the anisotropy, eradicates the negative travel speed, preserves the traveling waves and keeps the linear stability. Through a series of numerical experiments, it is concluded that (1) under the bi-directional looking context only when the backward weight ratio belongs to an appropriate range then the anisotropic property can be maintained; (2) forward-propagating traffic density waves and standing waves emerge with the increasing consideration ratio for backward information; (3) the more aggressive driving behaviors for the forward direction can delay the backward-propagating and speed up the forward-propagating of traffic density waves; (4) positive holding effect and negative pushing effect of backward looking can also be observed under different backward weight ratios; and (5) traffic flow stability varies with different proportion of backward traffic information contribution and such stability impact is sensitive to the initial traffic density condition. This proposed continuum model may contribute to future development of traffic control and coordination in future connected vehicle environment.


      PubDate: 2015-05-22T02:00:07Z
       
  • A simple algorithm for the estimation of road traffic space mean speeds
           from data available to most management centres
    • Abstract: Publication date: May 2015
      Source:Transportation Research Part B: Methodological, Volume 75
      Author(s): Margarita Martínez-Díaz , Ignacio Pérez
      The control of the evolution of road traffic streams is highly related to productivity, safety, sustainability and, even, comfort. Although, nowadays, the findings from research efforts and the development of new technologies enable accurate traffic forecasts in almost any conditions, these calculations are usually limited by the data and the equipment available. Most traffic management centres depend on the data provided, at best, by double-loop detectors. These loops supply time means over different aggregation periods, which are indiscriminately used as the bases for subsequent estimations. Since space mean speeds are those needed in most applications (note the fundamental relationship between flow and density in traffic flow theory), most current practice begins with an error. This paper introduces a simple algorithm that the allows estimation of space mean speeds from the data provided by the loops without the need for any additional financial outlay, as long as the traffic in each time interval of aggregation is stationary and its speed distribution is log-normal. Specifically, it is focused on the calculation of the variance of the speeds with regard to the time mean, thus making possible to use the relationship between time mean speeds and space mean speeds defined by Rakha (2005). The results obtained with real data show that the algorithm behaves well if the calculation conditions help fulfil the initial hypotheses. The primary difficulties arise with transient traffic and, in this case, other specific methodologies should be used. Data fusion seems promising in this regard. Nevertheless, it cannot be denied that the improvement provided by the algorithm turns out to be highly beneficial both when used alone in the case of stationarity or as a part of a fusion.


      PubDate: 2015-05-22T02:00:07Z
       
  • A tractable two-stage robust winner determination model for truckload
           service procurement via combinatorial auctions
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Bo Zhang , Tao Yao , Terry L. Friesz , Yuqi Sun
      A combinatorial auction is one of the adopted mechanisms for truckload (TL) service procurement. In such an auction, the shipper faces a well-known winner determination problem (WDP): the shipper, as the auctioneer, is given bids submitted by a group of carriers. In most literature, WDP is modeled as a deterministic mixed-integer program (MIP) and is solved by standard MIP algorithms. However, in practice, the exact shipping demand is unavailable until after the auction. This shipment volume uncertainty has a significant impact on the solution to WDP. Therefore, a deterministic winner determination model with an estimate of shipment volume may not provide solutions that attain low procurement costs. This paper proposes a new tractable two-stage robust optimization (RO) approach to solve WDP for TL service procurement under shipment volume uncertainty. Assuming that only historical data is available, we propose a data-driven approach based on the central limit theorem (CLT) to construct polyhedral uncertainty sets. In particular, we consider two random cases: independent shipment volume and correlated shipment volume. A two-stage RO model with integer first-stage decision variables and continuous recourse variables is then formulated. We develop a reformulation solution method and use numerical tests to demonstrate that it is much more computationally efficient than the widely adopted Benders’ type constraint generation algorithm. We demonstrate by numerical tests that real-world sized instances of TL service procurement problems can be solved by our proposed robust method. Moreover, we compare our robust approach with benchmark and show that it is more tractable and robust to uncertainty.


      PubDate: 2015-05-22T02:00:07Z
       
  • Infrastructure deployment under uncertainties and competition: The biofuel
           industry case
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Xin Wang , Michael K. Lim , Yanfeng Ouyang
      Technological paradigm shifts often come with a newly emerging industry that seeks a viable infrastructure deployment plan to compete against established competitors. Such phenomenon has been repeatedly seen in the field of transportation systems, such as those related to the booming bioenergy production, among others. We develop a game-theoretic modeling framework using a continuum approximation scheme to address the impacts of competition on the optimal infrastructure deployment. Furthermore, we extend the model to incorporate uncertainties in supply/demand and the risk of facility disruptions. Analytical properties of the optimal infrastructure system are obtained, based on which fast numerical solution algorithms are developed. Several hypothetical problem instances are used to illustrate the effectiveness of the proposed algorithms and to quantify the impacts of various system parameters. A large-scale biofuel industry case study for the U.S. Midwest is conducted to obtain additional managerial insights.


      PubDate: 2015-05-22T02:00:07Z
       
  • Planning, operation, and control of bus transport systems: A literature
           review
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77
      Author(s): O.J. Ibarra-Rojas , F. Delgado , R. Giesen , J.C. Muñoz
      The efficiency of a transport system depends on several elements, such as available technology, governmental policies, the planning process, and control strategies. Indeed, the interaction between these elements is quite complex, leading to intractable decision making problems. The planning process and real-time control strategies have been widely studied in recent years, and there are several practical implementations with promising results. In this paper, we review the literature on Transit Network Planning problems and real-time control strategies suitable to bus transport systems. Our goal is to present a comprehensive review, emphasizing recent studies as well as works not addressed in previous reviews.


      PubDate: 2015-05-22T02:00:07Z
       
  • Cordon toll competition in a network of two cities: Formulation and
           sensitivity to traveller route and demand responses
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76
      Author(s): D.P. Watling , S.P. Shepherd , A. Koh
      While there exists extensive literature on the first- and second-best tolling of congested transportation networks, much of it presumes the existence of a single agent responsible for toll-setting. The present paper extends the small but growing body of work studying the impact of several agents independently regulating tolls on different parts of a network. Specifically we consider the problem of a network consisting of two ‘cities’, each city independently regulated by a city ‘authority’ able to set a single cordon toll for entry to the city. It is supposed that each authority aims to maximise the social welfare of its own residents, anticipating the impact of its toll on travellers’ route and demand decisions, while reacting to the toll level levied by the other authority. In addition, we model the possibility of the cities entering into a ‘tax-exporting agreement’, in which city A agrees to share with city B the toll revenues it collects from city B residents using city A’s network. It is assumed that the sensitivity of travellers, in terms of their route and demand responses, is captured by an elastic demand, Stochastic User Equilibrium (SUE) model. Conditions for a Nash Equilibrium (NE) between cities are set out as an Equilibrium Problem with Equilibrium Constraints (EPEC). It is shown that weaker, ‘local’ solutions to the EPEC (which we term LNE for local NE) satisfy a single variational inequality, using the smooth implicit function of the SUE map. Standard variational algorithms may then be used to identify such LNE solutions, allowing NE solutions to be identified from this candidate set; we test the use of a Sequential Linear Complementarity Problem algorithm. Numerical results are reported in which we see that the sensitivity of travellers may affect many factors, including: the number of LNE solutions, the initial conditions for which algorithms might determine such solutions, the gap between LNE and a global regulator solution, and the incentive for cities to cooperate in terms of tax-exporting.


      PubDate: 2015-04-04T14:51:22Z
       
 
 
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