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  Subjects -> TRANSPORTATION (Total: 161 journals)
    - AIR TRANSPORT (7 journals)
    - AUTOMOBILES (20 journals)
    - RAILROADS (4 journals)
    - ROADS AND TRAFFIC (4 journals)
    - SHIPS AND SHIPPING (27 journals)
    - TRANSPORTATION (99 journals)

TRANSPORTATION (99 journals)

Accident Analysis & Prevention     Partially Free   (Followers: 41)
AI & Society     Hybrid Journal   (Followers: 2)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 1)
Archives of Transport     Open Access   (Followers: 6)
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   (Followers: 1)
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: 6)
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: 6)
International Journal of Electronic Transport     Hybrid Journal   (Followers: 2)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 7)
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: 9)
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: 7)
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: 5)
International Journal of Vehicular Technology     Open Access   (Followers: 3)
Journal of Advanced Transportation     Hybrid Journal   (Followers: 11)
Journal of Mechatronics, Electrical Power, and Vehicular Technology     Open Access   (Followers: 1)
Journal of Modern Transportation     Full-text available via subscription   (Followers: 1)
Journal of Navigation     Hybrid Journal   (Followers: 96)
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: 4)
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: 4)
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  
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: 8)
PS: Political Science & Politics     Full-text available via subscription   (Followers: 24)
Public Transport     Hybrid Journal   (Followers: 10)
Recherche Transports Sécurité     Hybrid Journal   (Followers: 2)
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: 13)
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: 2)
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: 6)
Transportation Letters : The International Journal of Transportation Research     Hybrid Journal  
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 27)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 26)
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: 33)
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: 4)
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]   [26 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0191-2615
   Published by Elsevier Homepage  [2811 journals]
  • Estimating bike-share trips using station level data
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Cyrille Médard de Chardon , Geoffrey Caruso
      Bicycle sharing systems (BSS) have increased in number rapidly since 2007. The potential benefits of BSS, mainly sustainability, health and equity, have encouraged their adoption through support and promotion by mayors in Europe and North America alike. In most cases municipal governments desire their BSS to be successful and, with few exceptions, state them as being so. New technological improvements have dramatically simplified the use and enforcement of bicycle return, resulting in the widespread adoption of BSS. Unfortunately little evaluation of the effectiveness of differently distributed and managed BSS has taken place. Comparing BSS systems quantitatively is challenging due to the limited data made available. The metrics of success presented by municipalities are often too general or incomparable to others making relative evaluations of BSS success arduous. This paper presents multiple methodologies allowing the estimation of the number of daily trips, the most significant measure of BSS usage, based on data that is commonly available, the number of bicycles available at a station over time. Results provide model coefficients as well as trip count estimates for select cities. Of four spatial and temporal aggregate models the day level aggregation is found to be most effective for estimation. In addition to trip estimation this work provides a rigorous formalization of station level data and the ability to distinguish spatio-temporal rebalancing quantities as well as new characteristics of BSS station use.
      Graphical abstract image

      PubDate: 2015-06-25T02:29:12Z
       
  • Robust weekly aircraft maintenance routing problem and the extension to
           the tail assignment problem
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Zhe Liang , Yuan Feng , Xiaoning Zhang , Tao Wu , Wanpracha Art Chaovalitwongse
      In this paper, we study two closely related airline planning problems: the robust weekly aircraft maintenance routing problem (RWAMRP) and the tail assignment problem (TAP). In real life operations, the RWAMRP solution is used in tactical planning whereas the TAP solution is implemented in operational planning. The main objective of these two problems is to minimize the total expected propagated delay (EPD) of the aircraft routes. To formulate the RWAMRP, we propose a novel weekly line-of-flights (LOF) network model that can handle complex and nonlinear cost functions of EPD. Because the number of LOFs grows exponentially with the number of flights to be scheduled, we propose a two-stage column generation approach to efficiently solve large-scale real-life RWAMRPs. Because the EPD of an LOF is highly nonlinear and can be very time-consuming to accurately compute, we propose three lower bounds on the EPD to solve the pricing subproblem of the column generation. Our approach is tested on eight real-life test instances. The computational results show that the proposed approach provides very tight LP relaxation (within 0.6% of optimal solutions) and solves the test case with more than 6000 flights per week in less than three hours. We also investigate the solutions obtained by our approach over 500 simulated realizations. The simulation results demonstrate that, in all eight test instances, our solutions result in less EPDs than those obtained from traditional methods. We then extend our model and solution approach to solve realistically simulated TAP instances.


      PubDate: 2015-06-25T02:29:12Z
       
  • Accounting for stochastic variables in discrete choice models
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Federico Díaz , Víctor Cantillo , Julian Arellana , Juan de Dios Ortúzar
      The estimation of discrete choice models requires measuring the attributes describing the alternatives within each individual’s choice set. Even though some attributes are intrinsically stochastic (e.g. travel times) or are subject to non-negligible measurement errors (e.g. waiting times), they are usually assumed fixed and deterministic. Indeed, even an accurate measurement can be biased as it might differ from the original (experienced) value perceived by the individual. Experimental evidence suggests that discrepancies between the values measured by the modeller and experienced by the individuals can lead to incorrect parameter estimates. On the other hand, there is an important trade-off between data quality and collection costs. This paper explores the inclusion of stochastic variables in discrete choice models through an econometric analysis that allows identifying the most suitable specifications. Various model specifications were experimentally tested using synthetic data; comparisons included tests for unbiased parameter estimation and computation of marginal rates of substitution. Model specifications were also tested using a real case databank featuring two travel time measurements, associated with different levels of accuracy. Results show that in most cases an error components model can effectively deal with stochastic variables. A random coefficients model can only effectively deal with stochastic variables when their randomness is directly proportional to the value of the attribute. Another interesting result is the presence of confounding effects that are very difficult, if not impossible, to isolate when more flexible models are used to capture stochastic variations. Due the presence of confounding effects when estimating flexible models, the estimated parameters should be carefully analysed to avoid misinterpretations. Also, as in previous misspecification tests reported in the literature, the Multinomial Logit model proves to be quite robust for estimating marginal rates of substitution, especially when models are estimated with large samples.


      PubDate: 2015-06-25T02:29:12Z
       
  • Port investments on coastal and marine disasters prevention: Economic
           modeling and implications
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Yi-bin Xiao , Xiaowen Fu , Adolf K.Y. Ng , Anming Zhang
      Located along shorelines, seaports are highly vulnerable to coastal and marine natural disasters largely due to climate change. Damage caused by disasters can be prevented or alleviated if sufficient investments are made in a timely manner. However, despite a wide range of investment options and well-developed engineering expertise, port investment on disaster prevention remains a challenging task involving great complexities. This paper develops an integrated economic model for the analysis of disaster-prevention investments at a “landlord” port. It simultaneously considers the uncertainty of disaster occurrence and associated return of prevention investments, the information accumulation and related investment timing, and the benefit spillovers of investment among stakeholders. Our analysis shows that the timing of port investments depends on the probability of disasters. Immediate investment is optimal for disasters with very high probability, while investment should be postponed if such a probability is very low. Optimal timing for cases of intermediate probability cannot be determined analytically, as it is influenced by other factors such as discount rate, information accumulation and efficiency of investments. Positive spillovers between a port and its tenants lead to under-investment, which can be corrected by coordination between stakeholders. However, since there are risks of “overinvestment” (the marginal benefits of investments are zero ex post if there is no disaster), regulatory intervention is not always optimal when the regulator does not have a good understanding of disaster probability distribution. Therefore, scientific research would bring significant economic and strategic value to policy, planning and investment decisions.


      PubDate: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • Editorial Board
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78




      PubDate: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • The recoverable robust facility location problem
    • Abstract: Publication date: September 2015
      Source:Transportation Research Part B: Methodological, Volume 79
      Author(s): Eduardo Álvarez-Miranda , Elena Fernández , Ivana Ljubić
      This work deals with a facility location problem in which location and allocation (transportation) policy is defined in two stages such that a first-stage solution should be robust against the possible realizations (scenarios) of the input data that can only be revealed in a second stage. This solution should be robust enough so that it can be recovered promptly and at low cost in the second stage. In contrast to some related modeling approaches from the literature, this new recoverable robust model is more general in terms of the considered data uncertainty; it can address situations in which uncertainty may be present in any of the following four categories: provider-side uncertainty, receiver-side uncertainty, uncertainty in-between, and uncertainty with respect to the cost parameters. For this novel problem, a sophisticated branch-and-cut framework based on Benders decomposition is designed and complemented by several non-trivial enhancements, including scenario sorting, dual lifting, branching priorities, matheuristics and zero-half cuts. Two large sets of instances that incorporate spatial and demographic information of countries such as Germany and US (transportation) and Bangladesh and the Philippines (disaster management) are introduced. They are used to analyze in detail the characteristics of the proposed model and the obtained solutions as well as the effectiveness, behavior and limitations of the designed algorithm.


      PubDate: 2015-06-25T02:29:12Z
       
  • A generalized queuing model and its solution properties
    • Abstract: Publication date: September 2015
      Source:Transportation Research Part B: Methodological, Volume 79
      Author(s): Jia Li , H.M. Zhang
      Modeling queuing behavior is central to the analysis of transportation and other service systems. To date, several queuing models been developed, but analytical insights on their global properties are hard to obtain. This is because in most cases, queuing dynamics are formulated as differential or difference equations, with possible discontinuities in their solutions, making most conventional analytical tools inadequate. As a result, simulations are often used to study these models, and if not properly treated, negative flows could arise from the simulation near certain discontinuities. In this paper, we propose a continuous-time queuing model that captures generalized queuing dynamics, where bottleneck discharging capacity and demand can vary simultaneously. We provide insights on the global properties of this model, upon deriving its closed-form variational solutions. Rather than resorting to the usual Hamilton–Jacobi theory, our derivations are built on an intrinsic periodicity property of the general queuing dynamics combined with measure-theoretic analysis. This treatment allows us to obtain results with more complex boundary conditions and make further extensions. We demonstrate its applications and show its solution properties in queuing simulation and performance bounding. In particular, we provide graphical, iterative and linearized solution schemes, which are all devoid of the well-known negative flow issue associated with numerical solutions to the point queue model.


      PubDate: 2015-06-25T02:29:12Z
       
  • A new generalized heterogeneous data model (GHDM) to jointly model mixed
           types of dependent variables
    • Abstract: Publication date: September 2015
      Source:Transportation Research Part B: Methodological, Volume 79
      Author(s): Chandra R. Bhat
      This paper formulates a generalized heterogeneous data model (GHDM) that jointly handles mixed types of dependent variables—including multiple nominal outcomes, multiple ordinal variables, and multiple count variables, as well as multiple continuous variables—by representing the covariance relationships among them through a reduced number of latent factors. Sufficiency conditions for identification of the GHDM parameters are presented. The maximum approximate composite marginal likelihood (MACML) method is proposed to estimate this jointly mixed model system. This estimation method provides computational time advantages since the dimensionality of integration in the likelihood function is independent of the number of latent factors. The study undertakes a simulation experiment within the virtual context of integrating residential location choice and travel behavior to evaluate the ability of the MACML approach to recover parameters. The simulation results show that the MACML approach effectively recovers underlying parameters, and also that ignoring the multi-dimensional nature of the relationship among mixed types of dependent variables can lead not only to inconsistent parameter estimation, but also have important implications for policy analysis.


      PubDate: 2015-06-25T02:29:12Z
       
  • Formulation, existence, and computation of boundedly rational dynamic user
           equilibrium with fixed or endogenous user tolerance
    • Abstract: Publication date: September 2015
      Source:Transportation Research Part B: Methodological, Volume 79
      Author(s): Ke Han , W.Y. Szeto , Terry L. Friesz
      This paper analyzes dynamic user equilibrium (DUE) that incorporates the notion of boundedly rational (BR) user behavior in the selection of departure times and routes. Intrinsically, the boundedly rational dynamic user equilibrium (BR-DUE) model we present assumes that travelers do not always seek the least costly route-and-departure-time choice. Rather, their perception of travel cost is affected by an indifference band describing travelers’ tolerance of the difference between their experienced travel costs and the minimum travel cost. An extension of the BR-DUE problem is the so-called variable tolerance dynamic user equilibrium (VT-BR-DUE) wherein endogenously determined tolerances may depend not only on paths, but also on the established path departure rates. This paper presents a unified approach for modeling both BR-DUE and VT-BR-DUE, which makes significant contributions to the model formulation, analysis of existence, solution characterization, and numerical computation of such problems. The VT-BR-DUE problem, together with the BR-DUE problem as a special case, is formulated as a variational inequality. We provide a very general existence result for VT-BR-DUE and BR-DUE that relies on assumptions weaker than those required for normal DUE models. Moreover, a characterization of the solution set is provided based on rigorous topological analysis. Finally, three computational algorithms with convergence results are proposed based on the VI and DVI formulations. Numerical studies are conducted to assess the proposed algorithms in terms of solution quality, convergence, and computational efficiency.


      PubDate: 2015-06-25T02:29:12Z
       
  • Some insights into a sequential resource allocation mechanism for en route
           air traffic management
    • Abstract: Publication date: September 2015
      Source:Transportation Research Part B: Methodological, Volume 79
      Author(s): Amy Kim , Mark Hansen
      This paper presents a game theoretic model of a sequential capacity allocation process in a congestible transportation system. In this particular application, we investigate the governing principles at work in how airlines will time their requests for en route resources under capacity shortfalls and uncertain conditions, when flights are not able to take their preferred route at their preferred departure time slot due to the shortfalls. We examine a sequential “First Submitted First Assigned” (FSFA) capacity allocation process within an en route air traffic flow management (ATFM) program such as the Collaborative Trajectory Options Program (CTOP), which is a Federal Aviation Administration initiative that aims to manage en route capacity constraints brought on by inclement weather and capacity/demand imbalances. In the FSFA process, flights are assigned the best available routes and slots available at the time flight operators submit their preference requests during the planning period, in a sequential manner. Because flight operators compete with one another for resources, in such an allocation process they would be expected to make their requests as early as possible. However, because weather and traffic conditions – and therefore, the values of resources – can change significantly, flight operators may prefer to request resources later in the process rather than earlier. We use a game theoretic setup to understand how flight operators might tradeoff these conflicts and choose an optimal time to submit their preferences for their flights, as submission times are competitive responses by flight operators looking to maximize their benefits. We first develop a loss function that captures the expected utility of submitting preferences under uncertainty about operating conditions. Then, a conceptual model of the FSFA process is constructed using a simultaneous incomplete information game, where flight operators compete for the “prizes” of having submitted their inputs before others. A numerical study is performed in which it is demonstrated that preference submission times are heavily influenced by the general uncertainty surrounding weather and operational conditions of the ATFM program, and each flight operator’s internal ability to handle this uncertainty. A key finding is that, in many of the scenarios presented, an optimal strategy for a flight operator is to submit their preferences at the very beginning of the planning period. If air traffic managers could expect to receive more submissions at the beginning of the planning period, they could more easily coordinate the ATFM program with other ATFM programs taking place or scheduled to take place, and they would have more opportunity to call another FSFA allocation route before the ATFM program begins, should conditions change enough to warrant this. Outputs of the model may provide some general insights to flight operators in planning submission strategies within competitive allocation processes such as FSFA. Also, this work may have a broader application to other sequential resource allocation strategies within congestible and controlled transportation systems.


      PubDate: 2015-06-25T02:29:12Z
       
  • Statistical approach for activity-based model calibration based on plate
           scanning and traffic counts data
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Treerapot Siripirote , Agachai Sumalee , H.W. Ho , William H.K. Lam
      Traditionally, activity-based models (ABM) are estimated from travel diary survey data. The estimated results can be biased due to low-sampling size and inaccurate travel diary data. For an accurate calibration of ABM parameters, a maximum-likelihood method that uses multiple sources of roadside observations (link counts and/or plate scanning data) is proposed. Plate scanning information (sensor path information) consists of sequences of times and partial paths that the scanned vehicles are observed over the preinstalled plate scanning locations. Statistical performances of the proposed method are evaluated on a test network using Monte Carlo technique for simulating the link flows and sensor path information. Multiday observations are simulated and derived from the true ABM parameters adopted in the choice models of activity pattern, time of the day, destination and mode. By assuming different number of plate scanning locations and identification rates, impacts of data quantity and data quality on ABM calibration are studied. The results illustrate the efficiency of the proposed model in using plate scanning information for ABM calibration and its potential for large and complex network applications.


      PubDate: 2015-06-25T02:29:12Z
       
  • Airline competition and market frequency: A comparison of the s-curve and
           schedule delay models
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Mark Hansen , Yi Liu
      We compare two common ways of incorporating service frequency into models of airline competition. One is based on the so called s-curve, in which, all else equal, market shares are determined by frequency shares. The other is based on schedule delay—the time difference between when travelers wish to travel and when flights are available. We develop competition models that differ only with regard to which of the above approaches is used to capture the effect of frequency. The demand side of both models is an approximation of a nested logit model which yields endogenous travel demand by including not traveling in the choice set. We find symmetric competitive equilibrium for both models analytically, and compare their predictions concerning market frequency with empirical evidence. In contrast to the s-curve model, the schedule delay model depicts a more plausible relationship between market share and frequency share and accurately predicts observed patterns of supply side behavior. Moreover, the predictions from both models are largely the same if we employ numerical versions of the model that capture real-world aspects of competition. We also find that, for either model, the relationship between airline frequency and market traffic is the same whether frequency is determined by competitive equilibrium, social optimality, or social optimality with a break-even constraint.


      PubDate: 2015-06-25T02:29:12Z
       
  • Transit technology investment and selection under urban population
           volatility: A real option perspective
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Zhi-Chun Li , Qian-Wen Guo , William H.K. Lam , S.C. Wong
      This paper addresses transit technology investment issues under urban population volatility using a real option approach. Two important problems are investigated: which transit technology should be selected and when should it be introduced. A real option model is proposed to incorporate explicitly the effects of transit technology investment on urban spatial structure in terms of households’ residential location choices and housing market. The trigger population thresholds for investing in a transit technology project and for shifting from a transit technology to another are explored analytically. Comparative static analyses of the urban system and transit technology investment are also carried out. It was found that (i) transit technology investment can induce urban sprawl; (ii) ignoring the effects of transit technology investment on urban spatial equilibrium can lead to a late investment; and (iii) there is a significant difference in the trigger population thresholds for transit technology shift estimated by the net present value approach and the real option approach.


      PubDate: 2015-06-25T02:29:12Z
       
  • Introducing non-normality of latent psychological constructs in choice
           modeling with an application to bicyclist route choice
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Chandra R. Bhat , Subodh K. Dubey , Kai Nagel
      In the current paper, we propose the use of a multivariate skew-normal (MSN) distribution function for the latent psychological constructs within the context of an integrated choice and latent variable (ICLV) model system. The multivariate skew-normal (MSN) distribution that we use is tractable, parsimonious in parameters that regulate the distribution and its skewness, and includes the normal distribution as a special interior point case (this allows for testing with the traditional ICLV model). Our procedure to accommodate non-normality in the psychological constructs exploits the latent factor structure of the ICLV model, and is a flexible, yet very efficient approach (through dimension-reduction) to accommodate a multivariate non-normal structure across all indicator and outcome variables in a multivariate system through the specification of a much lower-dimensional multivariate skew-normal distribution for the structural errors. Taste variations (i.e., heterogeneity in sensitivity to response variables) can also be introduced efficiently and in a non-normal fashion through interactions of explanatory variables with the latent variables. The resulting model we develop is suitable for estimation using Bhat’s (2011) maximum approximate composite marginal likelihood (MACML) inference approach. The proposed model is applied to model bicyclists’ route choice behavior using a web-based survey of Texas bicyclists. The results reveal evidence for non-normality in the latent constructs. From a substantive point of view, the results suggest that the most unattractive features of a bicycle route are long travel times (for commuters), heavy motorized traffic volume, absence of a continuous bicycle facility, and high parking occupancy rates and long lengths of parking zones along the route.


      PubDate: 2015-06-25T02:29:12Z
       
  • Scheduling heterogeneous train traffic on double tracks with efficient
           dispatching rules
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Xiaoming Xu , Keping Li , Lixing Yang
      To further improve the utilization rate of railway tracks and reduce train delays, this paper focuses on developing a high-efficiency train routing and timetabling approach for double-track railway corridors in condition that trains are allowable to travel on reverse direction tracks. We first design an improved switchable policy which is rooted in the approaches by Mu and Dessouky (2013), with the analysis of possible delays caused by different path choices. Then, three novel integrated train routing and timetabling approaches are proposed on the basis of a discrete event model and different dispatching rules, including no switchable policy (No-SP), Mu and Dessouky (2013)’s switchable policy (Original-SP) and improved switchable policy (Improved-SP). To demonstrate the performance of the proposed approaches, the heterogeneous trains on Beijing–Shanghai high speed railway are scheduled by aforementioned approaches. The case studies indicate that in comparison to No-SP and Original-SP approaches, respectively, the Improved-SP approach can reduce the total delay of trains up to 44.44% and 73.53% within a short computational time. Moreover, all of the performance criteria of the Improved-SP approach are usually better than those of other two approaches.


      PubDate: 2015-06-25T02:29:12Z
       
  • Data dependent input control for origin–destination demand
           estimation using observability analysis
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Yudi Yang , Yueyue Fan
      In this paper, we address the observability issue of static O–D estimation based on link counts. Unlike most classic observability analyses that relied only on network topological relationships, our analysis incorporates the actual values of input parameters, thus including network operational relations as well. We first analyze possible mathematical properties of an O–D estimation problem with different data input. We then propose a modeling approach based on mixed-integer program for selecting model input that ensures observability and estimation quality. Through establishing a stronger connection between observability analysis and the corresponding estimation problem, the proposed method aims to improve estimation quality while reducing reliance on erroneous data.


      PubDate: 2015-06-25T02:29:12Z
       
  • Joint service capacity planning and dynamic container routing in shipping
           network with uncertain demands
    • Abstract: Publication date: August 2015
      Source:Transportation Research Part B: Methodological, Volume 78
      Author(s): Jing-Xin Dong , Chung-Yee Lee , Dong-Ping Song
      Service capacity planning is a key tactic decision in container shipping, which has a significant impact on daily operations of shipping company. On the other hand, operational decisions such as demand fulfilment and shipment routing will impact on service capacity requirements and utilisation, particularly in the presence of demand uncertainty. This article proposes a two stage stochastic programming model with recourse to deal with the problem of joint service capacity planning and dynamic container routing in liner shipping. The first stage of the model concerns how to determine the optimal service capacity, and the second focuses on the optimal routing of shipments in stochastic and dynamic environments under a given service capacity plan. Initially, SAA (Sample Average Approximation) is employed to solve the model. Noting the computational complexity of the problem, Progressive Hedging Algorithm (PHA) is employed to decompose the SAA model into a number of scenario-based models so that reasonably large scale problems can be solved. To handle larger scale problems, we develop a new solution procedure termed as APHA (Adapted Progressive Hedging Algorithm) that further decomposes the scenario-based model into job (customer order) based models with measurable error bounds. Numerical experiments are conducted to illustrate the effectiveness of the proposed APHA in solving the problems under consideration.


      PubDate: 2015-06-25T02:29:12Z
       
  • Editorial Board
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part B: Methodological, Volume 77




      PubDate: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • 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: 2015-06-25T02:29:12Z
       
  • Robust transit network design with stochastic demand considering
           development density
    • Abstract: Publication date: Available online 16 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Kun An , Hong K. Lo
      This paper analyzes the influence of urban development density on transit network design with stochastic demand by considering two types of services, rapid transit services, such as rail, and flexible services, such as dial-a-ride shuttles. Rapid transit services operate on fixed routes and dedicated lanes, and with fixed schedules, whereas dial-a-ride services can make use of the existing road network, hence are much more economical to implement. It is obvious that the urban development densities to financially sustain these two service types are different. This study integrates these two service networks into one multi-modal network and then determines the optimal combination of these two service types under user equilibrium (UE) flows for a given urban density. Then we investigate the minimum or critical urban density required to financially sustain the rapid transit line(s). The approach of robust optimization is used to address the stochastic demands as captured in a polyhedral uncertainty set, which is then reformulated by its dual problem and incorporated accordingly. The UE principle is represented by a set of variational inequality (VI) constraints. Eventually, the whole problem is linearized and formulated as a mixed-integer linear program. A cutting constraint algorithm is adopted to address the computational difficulty arising from the VI constraints. The paper studies the implications of three different population distribution patterns, two CBD locations, and produces the resultant sequences of adding more rapid transit services as the population density increases.


      PubDate: 2015-06-25T02:29:12Z
       
  • A mechanism design based approach to solving parking slot assignment in
           the information era
    • Abstract: Publication date: Available online 11 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Bo Zou , Nabin Kafle , Ouri Wolfson , Jie (Jane) Lin
      This paper proposes a mechanism design based approach for public parking slot assignment in an environment empowered by recent advances in parking sensing, infrastructure-to-vehicle, and vehicle-to-infrastructure communications. An important part of the parking slot assignment deals with eliciting truthful private information from drivers while maximizing social welfare. We consider both static and dynamic mechanisms and provide theoretic proofs that, by using coupled slot allocation and payment rules, drivers will be incentivized to participate in the assignment process and truthfully report their private information. The parking manager will benefit by generating non-negative revenue from each assigned driver. Our numerical analysis provides further insights into the implementation of the dynamic mechanisms.


      PubDate: 2015-06-25T02:29:12Z
       
  • Modeling absolute and relative cost differences in stochastic user
           equilibrium problem
    • Abstract: Publication date: Available online 10 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Xiangdong Xu , Anthony Chen , Songyot Kitthamkesorn , Hai Yang , Hong K. Lo
      This paper aims to develop a hybrid closed-form route choice model and the corresponding stochastic user equilibrium (SUE) to alleviate the drawbacks of both Logit and Weibit models by simultaneously considering absolute cost difference and relative cost difference in travelers’ route choice decisions. The model development is based on an observation that the issues of absolute and relative cost differences are analogous to the negative exponential and power impedance functions of the trip distribution gravity model. Some theoretical properties of the hybrid model are also examined, such as the probability relationship among the three models, independence from irrelevant alternatives, and direct and indirect elasticities. To consider the congestion effect, we provide a unified modeling framework to formulate the Logit, Weibit and hybrid SUE models with the same entropy maximization objective but with different total cost constraint specifications representing the modelers’ knowledge of the system. With this, there are two ways to interpret the dual variable associated with the cost constraint: shadow price representing the marginal change in the entropy level to a marginal change in the total cost, and dispersion/shape parameter representing the travelers’ perceptions of travel costs. To further consider the route overlapping effect, a path-size factor is incorporated into the hybrid SUE model. Numerical examples are also provided to illustrate the capability of the hybrid model in handling both absolute and relative cost differences as well as the route overlapping problem in travelers’ route choice decisions.


      PubDate: 2015-06-25T02:29:12Z
       
  • On the existence of stationary states in general road networks
    • Abstract: Publication date: Available online 6 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Wen-Long Jin
      Our daily driving experience and empirical observations suggest that traffic patterns in a road network are relatively stationary during peak periods. In numerous transportation network studies, there has been an implicit conjecture that stationary states exist in a network when origin demands, route choice proportions, and destination supplies are constant. In this study, we first rigorously formulate the conjecture within the framework of a network kinematic wave theory with an invariant junction model. After defining stationary states, we derive a system of algebraic equations in 3-tuples of stationary link flow-rates, demands, and supplies. We then introduce a new definition of junction critical demand levels based on effective demands and supplies. With a map in critical demand levels, we show that its fixed points and, therefore, stationary states exist with the help of Brouwer’s fixed point theorem. For two simple road networks, we show that the map is well-defined and can be used to solve stationary states with a brute-force method. Finally we summarize the study and present some future extensions and applications.


      PubDate: 2015-06-25T02:29:12Z
       
  • A branch-and-cut algorithm for a realistic dial-a-ride problem
    • Abstract: Publication date: Available online 6 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Mengyang Liu , Zhixing Luo , Andrew Lim
      In this paper we study a realistic dial-a-ride problem which simultaneously considers multiple trips, heterogeneous vehicles, multiple request types, configurable vehicle capacity and manpower planning. All of these features originate from practical applications in recent years. To formulate the problem, we propose two mathematical models that use different methods to deal with requests associated with the depot. To further strengthen the models, we propose eight families of valid inequalities, and based on them, we propose a branch-and-cut algorithm to solve the problem. The branch-and-cut algorithm was extensively tested on a set of instances generated according to the data of a real world application. The computational results showed that seven families of inequalities can improve the lower bounds substantially and the branch-and-cut algorithm can solve instances with up to 22 requests within 4h.


      PubDate: 2015-06-25T02:29:12Z
       
  • A real-time bus dispatching policy to minimize passenger wait on a high
           frequency route
    • Abstract: Publication date: Available online 5 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Simon J. Berrebi , Kari E. Watkins , Jorge A. Laval
      One of the greatest problems facing transit agencies that operate high-frequency routes is maintaining stable headways and avoiding bus bunching. In this work, a real-time holding mechanism is proposed to dispatch buses on a loop-shaped route using real-time information. Holds are applied at one or several control points to minimize passenger waiting time while maintaining the highest possible frequency, i.e. using no buffer time. The bus dispatching problem is formulated as a stochastic decision process. The optimality equations are derived and the optimal holding policy is found by backward induction. A control method that requires much less information and that closely approximates the optimal dispatching policy is found. A simulation assuming stochastic operating conditions and unstable headway dynamics is performed to assess the expected average waiting time of passengers at stations. The proposed control strategy is found to provide lower passenger waiting time and better resiliency than methods used in practice and recommended in the literature.
      Graphical abstract image

      PubDate: 2015-06-25T02:29:12Z
       
  • Commuters’ preferences for fast and reliable travel: A
           semi-parametric estimation approach
    • Abstract: Publication date: Available online 4 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Paul R. Koster , Hans R.A. Koster
      We employ a semi-parametric estimation approach to analyse observed and unobserved heterogeneity in the value of savings in travel time and schedule delay. Our econometric approach allows for the estimation of unobserved and observed heterogeneity in preferences in a flexible way, meaning that we do not put any structure on how individual characteristics (such as income and age) relate to the value of savings in travel time and schedule delay. Using data from a stated choice experiment, we illustrate the estimation approach and find that there is substantial heterogeneity in the value of savings in travel time and schedule delay. For our data, we find that unobserved heterogeneity is more important than heterogeneity related to individual characteristics.


      PubDate: 2015-06-25T02:29:12Z
       
  • A modified Cell Transmission Model with realistic queue discharge features
           at signalized intersections
    • Abstract: Publication date: Available online 3 June 2015
      Source:Transportation Research Part B: Methodological
      Author(s): Anupam Srivastava , Wen-Long Jin , Jean-Patrick Lebacque
      Modeling realistic discharge flow-rate and headway features at signalized intersections is critical to the design of traffic signals, since they play a critical role in determining the startup lost times and intersection capacity. Traditional queue discharge models are either microscopic or stochastic, and macroscopic traffic flow models for signalized intersections are based on overly simplistic assumptions. They are incapable of modeling traffic dynamics at signalized intersections as well as capturing realistic queue discharge features. In this study we propose a modified Cell Transmission Model (CTM) by substituting the traditional demand function, which is constant under over-saturated conditions, with a linearly decreasing function. The new demand function is defined through a combination of conventional macroscopic parameters, including critical density, free-flow speed, jam density, and an additional parameter, jam demand. Analytically we show that the new model reproduces observed features in the discharge flow-rate and headway. We further present a new definition of lost times at the macroscopic level based on the modified CTM. Calibration with observations in existing studies, as well as new observations, further suggest that the model can reasonably capture all traffic queue discharge features. We also discuss solutions to the new model under various Riemann problem scenarios and show that they produce realistic results while offering observable improvements in the modeling of traffic dynamics under certain scenarios.


      PubDate: 2015-06-25T02:29:12Z
       
  • Editorial Board
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part B: Methodological, Volume 76




      PubDate: 2015-06-25T02:29:12Z
       
 
 
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