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  Subjects -> TRANSPORTATION (Total: 151 journals)
    - AIR TRANSPORT (6 journals)
    - AUTOMOBILES (20 journals)
    - RAILROADS (4 journals)
    - ROADS AND TRAFFIC (4 journals)
    - SHIPS AND SHIPPING (25 journals)
    - TRANSPORTATION (92 journals)

TRANSPORTATION (92 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)
Botswana Journal of Technology     Full-text available via subscription  
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: 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: 3)
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: 5)
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: 7)
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: 5)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 14)
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: 83)
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 Transport & Health     Hybrid Journal   (Followers: 2)
Journal of Transport and Land Use     Open Access   (Followers: 12)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 6)
Journal of Transport Geography     Hybrid Journal   (Followers: 16)
Journal of Transport History     Full-text available via subscription   (Followers: 10)
Journal of Transport Literature     Open Access  
Journal of Transportation Safety & Security     Hybrid Journal   (Followers: 8)
Journal of Transportation Security     Hybrid Journal   (Followers: 2)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 14)
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)
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: 5)
PS: Political Science & Politics     Full-text available via subscription   (Followers: 22)
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: 3)
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: 6)
Transportation     Hybrid Journal   (Followers: 18)
Transportation Geotechnics     Full-text available via subscription  
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 6)
Transportation Journal     Full-text available via subscription   (Followers: 5)
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 25)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 23)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 15)
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 29)
Transportation Science     Full-text available via subscription   (Followers: 14)
TRANSPORTES     Open Access   (Followers: 2)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 1)
Transportmetrica B : Transport Dynamics     Hybrid Journal  
Travel Behaviour and Society     Full-text available via subscription  
Travel Medicine and Infectious Disease     Hybrid Journal   (Followers: 2)
Urban, Planning and Transport Research     Open Access   (Followers: 3)
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]   [25 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0191-2615
   Published by Elsevier Homepage  [2588 journals]
  • Evaluation of a multimodal urban arterial: The passenger macroscopic
           fundamental diagram
    • Abstract: Publication date: Available online 19 March 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Nicolas Chiabaut
      This paper aims to extend the concept of macroscopic fundamental diagram (MFD) to combine different transportation modes. Especially, we propose a unified relationship that accounts for cars and buses because the classical MFD is not sufficient to capture the traffic flow interactions of a multimodal traffic. The concept of passenger macroscopic fundamental diagram (p-MFD) is introduced. With this new relationship, the efficiency of the global transport system, i.e. behaviors of cars and buses, can be assessed. Intuitively, the p-MFD shape strongly depends on the mode ratio. Thus, user equilibrium and system optimum are studied and compared. Finally, this relationship is used to design bus system characteristics and to identify the optimal domains of applications for different transit strategies.


      PubDate: 2015-03-20T15:13:22Z
       
  • 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: 2015-03-20T15:13:22Z
       
  • 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: 2015-03-20T15:13:22Z
       
  • 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: 2015-03-20T15:13:22Z
       
  • 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: 2015-03-20T15:13:22Z
       
  • Editorial Board
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73




      PubDate: 2015-03-16T07:11:18Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • A trial-and-error congestion pricing scheme for networks with elastic
           demand and link capacity constraints
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Bojian Zhou , Michiel Bliemer , Hai Yang , Jie He
      This paper proposes a combination of trial-and-error congestion pricing schemes that have been studied in the literature. It not only considers the minimization of the total system cost but also addresses the capacity constraints. A two-level iteration method is proposed for solving the hybrid problem, in which the approximate subgradient projection method is used for the outer level iteration phase, and the partial linearization method is used for the inner level iteration phase. We prove the convergence of the two-level iteration method, under the condition that the subproblem for the inner level iteration is only solved approximately, which makes the method efficient and practical. A numerical example is presented to illustrate the application of the two-level iteration method to the trial-and-error congestion pricing scheme.


      PubDate: 2015-03-04T01:30:39Z
       
  • Strategic considerations behind the network–regional airline tie ups
           – A theoretical and empirical study
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): David Gillen , Hamed Hasheminia , Changmin Jiang
      The paper examines the strategic vertical relationship between network and regional airlines. We develop a model to illustrate how network airlines can use the contractual relationship with regional airlines as an efficient tool to simultaneously drive out inefficient network airlines and also accommodate other cost efficient network airlines in any specific market. The model is tested on U.S. data using simultaneous and sequential choice models. We find that market size, cost differences between network airlines, as well as cost differences between network and regional airlines, are the chief determinants of the network airlines’ decisions on whether or not to serve a market with their own fleet, as well as how many regional airlines to contract with.


      PubDate: 2015-03-04T01:30:39Z
       
  • Profit-based maritime container assignment models for liner shipping
           networks
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Shuaian Wang , Zhiyuan Liu , Michael G.H. Bell
      We propose the problem of profit-based container assignment (P-CA), in which the container shipment demand is dependent on the freight rate, similar to the “elastic demand” in the literature on urban transportation networks. The problem involves determining the optimal freight rates, the number of containers to transport and how to transport the containers in a liner shipping network to maximize the total profit. We first consider a tactical-level P-CA with known demand functions that are estimated based on historical data and formulate it as a nonlinear optimization model. The tactical-level P-CA can be used for evaluating and improving the container liner shipping network. We then address the operational-level P-CA with unknown demand functions, which aims to design a mechanism that adjusts the freight rates to maximize the profit. A theoretically convergent trial-and-error approach, and a practical trial-and-error approach, are developed. A numerical example is reported to illustrate the application of the models and approaches.


      PubDate: 2015-03-04T01:30:39Z
       
  • Global optimization method for network design problem with stochastic user
           equilibrium
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Haoxiang Liu , David Z.W. Wang
      In this paper, we consider the continuous road network design problem with stochastic user equilibrium constraint that aims to optimize the network performance via road capacity expansion. The network flow pattern is subject to stochastic user equilibrium, specifically, the logit route choice model. The resulting formulation, a nonlinear nonconvex programming problem, is firstly transformed into a nonlinear program with only logarithmic functions as nonlinear terms, for which a tight linear programming relaxation is derived by using an outer-approximation technique. The linear programming relaxation is then embedded within a global optimization solution algorithm based on range reduction technique, and the proposed approach is proved to converge to a global optimum.


      PubDate: 2015-03-04T01:30:39Z
       
  • Optimal transit routing with partial online information
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Peng (Will) Chen , Yu (Marco) Nie
      This paper studies the routing strategy in a transit network with partial online information at stops. By partial online information, we mean that the arrival time of the incoming transit vehicles is available for a subset of the lines serving a stop. To cope with the partial information assumption, a new routing strategy is proposed and closed form formulae for computing expected waiting times and line boarding probabilities are derived. The proposed strategy unifies existing hyperpath-based transit route choice models that assume either no information or full information. Like many existing models, it ensures optimality when all information is available or the headway is exponentially distributed. The problem of determining the attractive set is discussed for each of the three information cases. In particular, a new heuristic algorithm is developed to generate the attractive set in the partial information case, which will always yield a solution no worse than that obtained without any information. The paper also reveals that, when information is available, an optimal hyperpath may contain cycles. Accordingly, the cause of such cycles is analyzed, and a sufficient condition that excludes cycles from optimal hyperpaths is proposed. Finally, numerical experiments are conducted to illustrate the impact of information availability on expected travel times and transit line load distributions. Among other findings, the results suggest that it is more useful to have information on faster lines than on slower lines.


      PubDate: 2015-03-04T01:30:39Z
       
  • A comparison of price-cap and light-handed airport regulation with demand
           uncertainty
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Hangjun Yang , Xiaowen Fu
      This study analytically compares the performance of ex ante price-cap airport regulation vs. ex post light-handed airport regulation in the presence of demand uncertainty. Our modeling results suggest that light-handed regulation is a promising method which may lead to higher welfare than price-cap regulation. However, neither regulation strictly dominates the other in terms of welfare, airport charge or service quality. The relative performance of alternative regulations depends on many market factors and the specification of penalty under light-handed regulation. Our analytical results also suggest that if service quality matters and if an airport is allowed to invest in a higher quality, average cost pricing may not be optimal due to possible sub-optimal choices of quality, and the overall performance of alternative regulatory regimes should be assessed with a comprehensive welfare analysis. Our investigation confirms that light-handed regulation is worth preserving subject to monitoring and continuous improvements.


      PubDate: 2015-03-04T01:30:39Z
       
  • Editorial Board
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72




      PubDate: 2015-03-04T01:30:39Z
       
  • A tailored branch-and-price approach for a joint tramp ship routing and
           bunkering problem
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Qiang Meng , Shuaian Wang , Chung-Yee Lee
      This paper deals with a practical tramp ship routing problem while taking into account different bunker prices at different ports, which is called the joint tramp ship routing and bunkering (JSRB) problem. Given a set of cargoes to be transported and a set of ports with different bunker prices, the proposed problem determines how to route ships to carry the cargoes and the amount of bunker to purchase at each port, in order to maximize the total profit. After building an integer linear programming model for the JSRB problem, we propose a tailored branch-and-price (B&P) solution approach. The B&P approach incorporates an efficient method for obtaining the optimal bunkering policy and a novel dominance rule for detecting inefficient routing options. The B&P approach is tested with randomly generated large-scale instances derived from real-world planning problems. All of the instances can be solved efficiently. Moreover, the proposed approach for the JSRB problem outperforms the conventional sequential planning approach and can incorporate the prediction of future cargo demand to avoid making myopic decisions.


      PubDate: 2015-03-04T01:30:39Z
       
  • Optimization of mid-block pedestrian crossing network with discrete
           demands
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Chunhui Yu , Wanjing Ma , Hong K. Lo , Xiaoguang Yang
      In many cases, pedestrian crossing demands are distributed discretely along an arterial segment. Demand origins, destinations and crosswalks comprise a pedestrian crossing network. An integrated model for optimizing the quantity, locations and signal settings of mid-block crosswalks simultaneously is proposed to best trade-off the operational performances between pedestrians and vehicles. Pedestrian behavior of choosing crosswalks is captured under a discrete demand distribution. Detour distance and delay at signalized crosswalks are formulated as a measure of pedestrian crossing cost. Maximum bandwidths are modeled in analytical expressions as a measure of vehicular cost. To solve the proposed model, the Non-dominated Sorting Genetic Algorithm II (NSGA II) based algorithm is designed and employed to obtain the Pareto frontier efficiently. From the numerical study, it is found that there exists an optimal number of mid-block crosswalks. Excess available crosswalks may make no contributions to improvement in pedestrian cost when the constraint of the minimum interval between crosswalks and vehicular cost are taken into account. Two-stage crosswalks are more favorable than one-stage ones for the benefits of both pedestrian and vehicles. The study results show promising properties of the proposed method to assist transportation engineers in properly designing mid-block crosswalks along a road segment.


      PubDate: 2015-03-04T01:30:39Z
       
  • On the fundamental diagram for freeway traffic: A novel calibration
           approach for single-regime models
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Xiaobo Qu , Shuaian Wang , Jin Zhang
      The speed-density or flow-density relationship has been considered as the foundation of traffic flow theory. Existing single-regime models calibrated by the least square method (LSM) could not fit the empirical data consistently well both in light-traffic/free-flow conditions and congested/jam conditions. In this paper, first, we point out that the inaccuracy of single-regime models is not caused solely by their functional forms, but also by the sample selection bias. Second, we apply a weighted least square method (WLSM) that addresses the sample selection bias problem. The calibration results for six well-known single-regime models using the WLSM fit the empirical data reasonably well both in light-traffic/free-flow conditions and congested/jam conditions. Third, we conduct a theoretical investigation that reveals the deficiency associated with the LSM is because the expected value of speed (or a function of it) is nonlinear with regard to the density (or a function of it).


      PubDate: 2015-03-04T01:30:39Z
       
  • Analysis of fixed-time control
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Ajith Muralidharan , Ramtin Pedarsani , Pravin Varaiya
      The paper presents an analysis of the traffic dynamics in a network of signalized intersections. The intersections are regulated by fixed-time (FT) controls, all with the same cycle length or period, T. The network is modeled as a queuing network. Vehicles arrive from outside the network at entry links in a deterministic periodic stream, also with period T. They take a fixed time to travel along each link, and at the end of the link they join a queue. There is a separate queue at each link for each movement or phase. Vehicles make turns at intersections in fixed proportions, and eventually leave the network, that is, a fraction r ( i , j ) of vehicles that leave queue i go to queue j and the fraction [ 1 - ∑ j r ( i , j ) ] leave the network. The storage capacity of the queues is infinite, so there is no spill back. The main contribution of the paper is to show that if the signal controls accommodate the demands then, starting in any initial condition, the network state converges to a unique periodic orbit. Thus, the effect of initial conditions disappears. More precisely, the state of the network at time t is the vector x ( t ) of all queue lengths, together with the position of vehicles traveling along the links. Suppose that the network is stable, that is, x ( t ) is bounded. Then (1) there exists a unique periodic trajectory x ∗ , with period T; (2) every trajectory converges to this periodic trajectory; (3) if vehicles do not follow loops, the convergence occurs in finite time. The periodic trajectory determines the performance of the entire network.


      PubDate: 2015-03-04T01:30:39Z
       
  • Bid price optimization for truckload carriers in simultaneous
           transportation procurement auctions
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Gültekin Kuyzu , Çağla Gül Akyol , Özlem Ergun , Martin Savelsbergh
      We study simultaneous transportation procurement auctions from a truckload carrier’s perspective. We formulate a stochastic bid price optimization model aimed at maximizing the carrier’s expected profit. The model accounts for synergies among lanes and competing carriers’ bid patterns. We develop an iterative coordinate search algorithm to find high-quality solutions. The benefits of employing the bid price optimization technology are demonstrated through computational experiments involving a simulated marketplace.


      PubDate: 2015-03-04T01:30:39Z
       
  • Method for investigating intradriver heterogeneity using vehicle
           trajectory data: A Dynamic Time Warping approach
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Jeffrey Taylor , Xuesong Zhou , Nagui M. Rouphail , Richard J. Porter
      After first extending Newell’s car-following model to incorporate time-dependent parameters, this paper describes the Dynamic Time Warping (DTW) algorithm and its application for calibrating this microscopic simulation model by synthesizing driver trajectory data. Using the unique capabilities of the DTW algorithm, this paper attempts to examine driver heterogeneity in car-following behavior, as well as the driver’s heterogeneous situation-dependent behavior within a trip, based on the calibrated time-varying response times and critical jam spacing. The standard DTW algorithm is enhanced to address a number of estimation challenges in this specific application, and a numerical experiment is presented with vehicle trajectory data extracted from the Next Generation Simulation (NGSIM) project for demonstration purposes. The DTW algorithm is shown to be a reasonable method for processing large vehicle trajectory datasets, but requires significant data reduction to produce reasonable results when working with high resolution vehicle trajectory data. Additionally, singularities present an interesting match solution set to potentially help identify changing driver behavior; however, they must be avoided to reduce analysis complexity.


      PubDate: 2015-03-04T01:30:39Z
       
  • GHG-emission models for assessing the eco-friendliness of road and rail
           freight transports
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Thomas Kirschstein , Frank Meisel
      Intermodal rail/road transportation is an instrument of green logistics, which may help reducing transport related greenhouse gas (GHG) emissions. In order to assess the environmental impact of road and rail transports, researchers have formulated very detailed microscopic models, which determine vehicle emissions precisely based on a vast number of parameters. They also developed macroscopic models, which estimate emissions more roughly from few parameters that are considered most influential. One of the goals of this paper is to develop mesoscopic models that combine the preciseness of micro-models while requiring only little more information than macro-models. We propose emission models designed for transport planning purposes which are simple to calibrate by transport managers. Despite their compactness, our models are able to reflect the influence of various traffic conditions on a transport’s total emissions. Furthermore, contrasting most papers considering either the road or the rail mode, we provide models on a common basis for both modes of transportation. We validate our models using popular micro- and macroscopic models and we apply them to artificial and real world transport scenarios to identify under which circumstances intermodal transports actually effect lower emissions. We find that travel speed and country-specific energy emission factors influence the eco-friendliness of intermodal transports most severely. Hence, the particular route chosen for a transnational intermodal transport is an important but so far neglected option for eco-friendly transportation.


      PubDate: 2015-03-04T01:30:39Z
       
  • Pricing of parking games with atomic players
    • Abstract: Publication date: March 2015
      Source:Transportation Research Part B: Methodological, Volume 73
      Author(s): Fang He , Yafeng Yin , Zhibin Chen , Jing Zhou
      This paper considers a parking competition game where a finite number of vehicles from different origins compete for the same number of parking spaces located at various places in a downtown area to minimize their own parking costs. If one vehicle reaches a desired vacant parking space before another vehicle, it will occupy the space and the other vehicle would have to search elsewhere. We first present a system of nonlinear equations to describe the equilibrium assignment of parking spaces to vehicles, and then discuss optimal pricing schemes that steer such parking competition to a system optimum assignment of parking spaces. These schemes are characterized by a union of polyhedrons. Given that the equilibrium state of parking competition is not unique, we further introduce a valid price vector to ensure that the parking competition outcome will always be system optimum. A sufficient condition is provided for the existence of such a valid price vector. Lastly, we seek for a robust price vector that yields the best worst-case outcome of the parking competition.


      PubDate: 2015-03-04T01:30:39Z
       
  • Approximation methods for large-scale spatial queueing systems
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Burak Boyacı , Nikolas Geroliminis
      Different than the conventional queueing systems, in spatial queueing systems (SQS) the service rate for each customer-server pairs differs and the server that intervenes for a specific customer is not known a priori, depending on the availability of servers at the moment a request was made. These features make the SQS computationally expensive (almost intractable for large scale) but at the same time more suitable for real-life problems with high reliability expectations. Emergency response and on-demand transportation systems are two similar systems that can be modeled with the SQS. In this research, we aim to solve facility location problems as SQS with stochastic demand and service time. The stochasticity concerned here is temporal and spatial, that emerges from the uncertainty in the demand and service time. In order to tackle this problem Larson (1974)’s 2 n hypercube queueing model (HQM) is extended to 3 n HQM. In this model, there are two different possible service types for each server: (i) service for locations in the proximity of a server (area of responsibility) and (ii) service for other locations where the first responsible server is busy during this event. In addition, to decrease the dimension of the problem, which is intractable due to their size, a new 3 n aggregate hypercube queueing model (AHQM) is developed that treats group of servers (bins) in a similar manner by considering interactions among bins. An efficient graph partitioning algorithm is proposed to cluster servers in groups with an objective to minimize the interactions among groups. Both exact and approximate approaches are integrated inside two optimization methods (i.e. variable neighborhood search and simulated annealing) to find server locations that improve system performance. Computational experiments showed that both models are applicable to use inside optimization algorithms to find good server locations and to improve system performance measures of SQS.


      PubDate: 2015-03-04T01:30:39Z
       
  • Would competition between air transport and high-speed rail benefit
           environment and social welfare?
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Tiziana D’Alfonso , Changmin Jiang , Valentina Bracaglia
      We develop a duopoly model to analyze the impact of air transport and high-speed rail (HSR) competition on the environment and social welfare. We show that the introduction of HSR may have a net negative effect on the environment, since it may result in additional demand, i.e., there is a trade-off between the substitution effect and the traffic generation effect. Furthermore, if environmental externalities are taken into account when assessing social welfare, the surplus measure may be higher when only air transport serves the market than when the two modes compete. When the airline and the HSR operator decide frequencies, the airline reduces the aircraft size in order to keep load factors high while offering lower frequency and carrying fewer passengers. In these circumstances, the introduction of HSR may be beneficial to the environment on a per seat basis only if the market size is large enough. When the HSR operator decides speed, it has incentive to keep it at the maximum level in order to reduce travel time. When the increase in the emissions of HSR due to the increase in the speed of the train is sufficiently high, the overall level of emissions grows after the introduction of HSR. Therefore, there can be a trade-off between the attractiveness of the service due to reduced travel time and the effects on the environment.


      PubDate: 2015-03-04T01:30:39Z
       
  • A Lagrangian heuristic framework for a real-life integrated planning
           problem of railway transportation resources
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Stéphane Dauzère-Pérès , David De Almeida , Olivier Guyon , Faten Benhizia
      Train path (infrastructure), rolling stock and crew scheduling are three critical planning decisions in railway transportation. These resources are usually planned separately in a sequential process that typically starts from planning (1) train paths and goes further on to (2) rolling stock and (3) train drivers. Such a sequential approach helps to handle the complexity of the planning process and simplify the underlying mathematical models. However, it generates solutions with higher costs because the decisions taken at one step can drastically reduce the set of feasible solutions in the following steps. In this paper, we propose a Lagrangian heuristic framework to solve an integrated problem which globally and simultaneously considers the planning of two railway resources: Rolling stock units and train drivers. Based on a mixed integer linear programming formulation, this approach has two important characteristics in an industrial context: (i) It can tackle real-life integrated planning problems and (ii) the Lagrangian dual is solved by calling two proprietary software modules available at SNCF. Various relaxation schemes are analyzed. Moreover, coupling constraints are rewritten to improve the heuristic effectiveness. Numerical experiments on real-life instances illustrate the effectiveness of the Lagrangian heuristic, and the impact of various parameters is analyzed. Compared to a sequential approach, it leads to cost reductions and generates good solutions in a reasonable CPU time.


      PubDate: 2015-03-04T01:30:39Z
       
  • Dynamic stride length adaptation according to utility and personal space
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Isabella von Sivers , Gerta Köster
      Pedestrians adjust both speed and stride length when they navigate difficult situations such as tight corners or dense crowds. They try to avoid collisions and to preserve their personal space. State-of-the-art pedestrian motion models automatically reduce speed in dense crowds simply because there is no space where the pedestrians could go. The stride length and its correct adaptation, however, are rarely considered. This leads to artefacts that impact macroscopic observation parameters such as densities in front of bottlenecks and, through this, flow. Hence modelling stride adaptation is important to increase the predictive power of pedestrian models. To achieve this we reformulate the problem as an optimisation problem on a disk around the pedestrian. Each pedestrian seeks the position that is most attractive in a sense of balanced goals between the search for targets, the need for individual space and the need to keep a distance from obstacles. The need for space is modelled according to findings from psychology defining zones around a person that, when invaded, cause unease. The result is a fully automatic adjustment that allows calibration through meaningful social parameters and that gives visually natural results with an excellent fit to measured experimental data.


      PubDate: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • Continuous formulations and analytical properties of the link transmission
           model
    • Abstract: Publication date: April 2015
      Source:Transportation Research Part B: Methodological, Volume 74
      Author(s): Wen-Long Jin
      The link transmission model (LTM) has great potential for simulating traffic flow in large-scale networks since it is much more efficient and accurate than the Cell Transmission Model (CTM). However, there lack general continuous formulations of LTM, and there has been no systematic study on its analytical properties such as stationary states and stability of network traffic flow. In this study we attempt to fill the gaps. First we apply the Hopf–Lax formula to derive Newell’s simplified kinematic wave model with given boundary cumulative flows and the triangular fundamental diagram. We then apply the Hopf–Lax formula to define link demand and supply functions, as well as link queue and vacancy functions, and present two continuous formulations of LTM, by incorporating boundary demands and supplies as well as invariant macroscopic junction models. With continuous LTM, we define and solve the stationary states in a road network. We also apply LTM to directly derive a Poincaré map to analyze the stability of stationary states in a diverge-merge network. Finally we present an example to show that LTM is not well-defined with non-invariant junction models. We can see that Newell’s model and continuous LTM complement each other and provide an alternative formulation of the network kinematic wave theory. This study paves the way for further extensions, analyses, and applications of LTM in the future.


      PubDate: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • A case study on the coordination of last trains for the Beijing subway
           network
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Liujiang Kang , Jianjun Wu , Huijun Sun , Xiaoning Zhu , Ziyou Gao
      Passengers may make several transfers between different lines to reach their destinations in urban railway transit networks. Coordination of last trains in feeding lines and connecting lines at transfer stations is especially important because it is the last chance for many travellers to transfer. In this paper, a mathematical method is used to reveal the relationships between passenger transfer connection time (PTCT) and passenger transfer waiting time (PTWT). A last-train network transfer model (LNTM) is established to maximize passenger transfer connection headways (PTCH), which reflect last-train connections and transfer waiting time. Additionally, a genetic algorithm (GA) is developed based upon this LNTM model and used to test a numerical example to verify its effectiveness. Finally, the Beijing subway network is taken as a case study. The results of the numerical example show that the model improves five connections and reduces to zero the number of cases when a feeder train arrives within one headway’s time after the connecting train departed.


      PubDate: 2015-03-04T01:30:39Z
       
  • Segment-based alteration for container liner shipping network design
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Shuaian Wang , Zhiyuan Liu , Qiang Meng
      Container liner shipping companies only partially alter their shipping networks to cope with the changing demand, rather than entirely redesign and change the network. In view of the practice, this paper proposes an optimal container liner shipping network alteration problem based on an interesting idea of segment, which is a sequence of legs from a head port to a tail port that are visited by the same type of ship more than once in the existing shipping network. In segment-based network alteration, the segments are intact and each port is visited by the same type of ship and from the same previous ports. As a result, the designed network needs minimum modification before implementation. A mixed-integer linear programming model with a polynomial number of variables is developed for the proposed segmented-based liner shipping network alternation problem. The developed model is applied to an Asia–Europe–Oceania liner shipping network with a total of 46 ports and 11 ship routes. Results demonstrate that the problem could be solved efficiently and the optimized network reduces the total cost of the initial network considerably.


      PubDate: 2015-03-04T01:30:39Z
       
  • Compromising system and user interests in shelter location and evacuation
           planning
    • Abstract: Publication date: February 2015
      Source:Transportation Research Part B: Methodological, Volume 72
      Author(s): Vedat Bayram , Barbaros Ç. Tansel , Hande Yaman
      Traffic management during an evacuation and the decision of where to locate the shelters are of critical importance to the performance of an evacuation plan. From the evacuation management authority’s point of view, the desirable goal is to minimize the total evacuation time by computing a system optimum (SO). However, evacuees may not be willing to take long routes enforced on them by a SO solution; but they may consent to taking routes with lengths not longer than the shortest path to the nearest shelter site by more than a tolerable factor. We develop a model that optimally locates shelters and assigns evacuees to the nearest shelter sites by assigning them to shortest paths, shortest and nearest with a given degree of tolerance, so that the total evacuation time is minimized. As the travel time on a road segment is often modeled as a nonlinear function of the flow on the segment, the resulting model is a nonlinear mixed integer programming model. We develop a solution method that can handle practical size problems using second order cone programming techniques. Using our model, we investigate the importance of the number and locations of shelter sites and the trade-off between efficiency and fairness.


      PubDate: 2015-03-04T01:30:39Z
       
  • Editorial Board
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71




      PubDate: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • 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: 2015-03-04T01:30:39Z
       
  • Microscopic driving theory with oscillatory congested states: Model and
           empirical verification
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Junfang Tian , Martin Treiber , Shoufeng Ma , Bin Jia , Wenyi Zhang
      The essential distinction between the Fundamental Diagram Approach (FDA) and Kerner’s three-phase theory (KTPT) is the existence of a unique gap–speed (or flow–density) relationship in the former class. In order to verify this relationship, empirical data are analyzed with the following findings: (1) linear relationship between the actual space gap and speed can be identified when the speed difference between vehicles approximates zero; (2) vehicles accelerate or decelerate around the desired space gap most of the time. To explain these phenomena, we propose that, in congested traffic flow, the space gap between two vehicles will oscillate around the desired space gap in the deterministic limit. This assumption is formulated in terms of a cellular automaton. In contrast to FDA and KTPT, the new model does not have any congested steady-state solution. Simulations under periodic and open boundary conditions reproduce the empirical findings of KTPT. Calibrating and validating the model to detector data produces results that are better than that of previous studies.


      PubDate: 2015-03-04T01:30:39Z
       
  • The load-dependent vehicle routing problem and its pick-up and delivery
           extension
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Emmanouil E. Zachariadis , Christos D. Tarantilis , Chris T. Kiranoudis
      The present paper examines a Vehicle Routing Problem (VRP) of major practical importance which is referred to as the Load-Dependent VRP (LDVRP). LDVRP is applicable for transportation activities where the weight of the transported cargo accounts for a significant part of the vehicle gross weight. Contrary to the basic VRP which calls for the minimization of the distance travelled, the LDVRP objective is aimed at minimizing the total product of the distance travelled and the gross weight carried along this distance. Thus, it is capable of producing sensible routing plans which take into account the variation of the cargo weight along the vehicle trips. The LDVRP objective is closely related to the total energy requirements of the vehicle fleet, making it a credible alternative when the environmental aspects of transportation activities are examined and optimized. A novel LDVRP extension which considers simultaneous pick-up and delivery service is introduced, formulated and solved for the first time. To deal with large-scale instances of the examined problems, we propose a local-search algorithm. Towards an efficient implementation, the local-search algorithm employs a computational scheme which calculates the complex weighted-distance objective changes in constant time. Solution results are presented for both problems on a variety of well-known test cases demonstrating the effectiveness of the proposed solution approach. The structure of the obtained LDVRP and VRP solutions is compared in pursuit of interesting conclusions on the relative suitability of the two routing models, when the decision maker must deal with the weighted distance objective. In addition, results of a branch-and-cut procedure for small-scale instances of the LDVRP with simultaneous pick-ups and deliveries are reported. Finally, extensive computational experiments have been performed to explore the managerial implications of three key problem characteristics, namely the deviation of customer demands, the cargo to tare weight ratio, as well as the size of the available vehicle fleet.


      PubDate: 2015-03-04T01:30:39Z
       
  • The kinematic wave model with finite decelerations: A social force
           car-following model approximation
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Rafael Delpiano , Jorge Laval , Juan Enrique Coeymans , Juan Carlos Herrera
      This paper derives a five-parameter social force car-following model that converges to the kinematic wave model with triangular fundamental diagram. Analytical solutions for vehicle trajectories are found for the lead-vehicle problem, which exhibit clockwise and counter-clockwise hysteresis depending on the model’s parameters and the lead vehicle trajectory. When coupled with a stochastic vehicle dynamics module, the model is able to reproduce periods and amplitudes of stop-and-go waves, as reported in the field. The model’s stability conditions are analysed and its trajectories are compared to real data.


      PubDate: 2015-03-04T01:30:39Z
       
  • Bidirectional pedestrian fundamental diagram
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Gunnar Flötteröd , Gregor Lämmel
      This article presents a new model of stationary bidirectional pedestrian flow. Starting out from microscopic first principles, a bidirectional fundamental diagram (FD) is derived that defines direction-specific flow rates as functions of direction-specific densities. The FD yields non-negative and bounded flows and guarantees that the instantaneous density changes that would result from these flows stay bounded between zero and jam density. In its minimal configuration, it uses just as many parameters as a unidirectional triangular FD: maximum walking speed, jam density, a collision avoidance parameter (from which the backward wave speed can be derived). A one-on-one mapping between the parameters guiding uni- and bidirectional pedestrian flows is proposed and both conceptually and empirically justified. Generalizations of the FD that maintain its desirable properties turn out to be straightforward by making its parameters density-dependent. The FD performs very well in comparisons against simulated and real data.


      PubDate: 2015-03-04T01:30:39Z
       
  • Entropy weighted average method for the determination of a single
           representative path flow solution for the static user equilibrium traffic
           assignment problem
    • Abstract: Publication date: January 2015
      Source:Transportation Research Part B: Methodological, Volume 71
      Author(s): Amit Kumar , Srinivas Peeta
      The formulation of the static user equilibrium traffic assignment problem (UETAP) under some simplifying assumptions has a unique solution in terms of link flows but not in terms of path flows. Large variations are possible in the path flows obtained using different UETAP solution algorithms. Many transportation planning and management applications entail the need for path flows. This raises the issue of generating a meaningful path flow solution in practice. Past studies have sought to determine a single path flow solution using the maximum entropy concept. This study proposes an alternate approach to determine a single path flow solution that represents the entropy weighted average of the UETAP path flow solution space. It has the minimum expected Euclidean distance from all other path flow solution vectors of the UETAP. The mathematical model of the proposed entropy weighted average method is derived and its solution stability is proved. The model is easy to interpret and generalizes the proportionality condition of Bar-Gera and Boyce (1999). Results of numerical experiments using networks of different sizes suggest that the path flow solutions for the UETAP using the proposed method are about identical to those obtained using the maximum entropy approach. The entropy weighted average method requires low computational effort and is easier to implement, and can therefore serve as a potential alternative to the maximum entropy approach in practice.


      PubDate: 2015-03-04T01:30:39Z
       
 
 
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