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

TRANSPORTATION (99 journals)

Accident Analysis & Prevention     Partially Free   (Followers: 40)
AI & Society     Hybrid Journal   (Followers: 2)
Analytic Methods in Accident Research     Hybrid Journal  
Archives of Transport     Open Access   (Followers: 5)
Bitácora Urbano-Territorial     Open Access   (Followers: 2)
Botswana Journal of Technology     Full-text available via subscription  
Case Studies on Transport Policy     Hybrid Journal  
Cities in the 21st Century     Open Access   (Followers: 11)
Economics of Transportation     Partially Free   (Followers: 10)
Emission Control Science and Technology     Hybrid Journal  
EURO Journal of Transportation and Logistics     Hybrid Journal   (Followers: 4)
European Transport Research Review     Open Access   (Followers: 13)
Geosystem Engineering     Hybrid Journal   (Followers: 3)
IATSS Research     Open Access  
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 5)
IET Electrical Systems in Transportation     Hybrid Journal   (Followers: 6)
IET Intelligent Transport Systems     Hybrid Journal   (Followers: 5)
International Innovation – Transport     Open Access   (Followers: 4)
International Journal of Applied Logistics     Full-text available via subscription   (Followers: 5)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 4)
International Journal of Critical Infrastructure Protection     Hybrid Journal   (Followers: 6)
International Journal of e-Navigation and Maritime Economy     Open Access  
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 5)
International Journal of Electronic Transport     Hybrid Journal   (Followers: 2)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
International Journal of Intelligent Transportation Systems Research     Hybrid Journal   (Followers: 5)
International Journal of Micro-Nano Scale Transport     Full-text available via subscription   (Followers: 2)
International Journal of Mobile Communications     Hybrid Journal   (Followers: 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: 6)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 16)
International Journal of Transportation Science and Technology     Full-text available via subscription   (Followers: 5)
International Journal of Vehicle Systems Modelling and Testing     Hybrid Journal   (Followers: 4)
International Journal of Vehicular Technology     Open Access   (Followers: 2)
Journal of Advanced Transportation     Hybrid Journal   (Followers: 11)
Journal of Modern Transportation     Full-text available via subscription   (Followers: 1)
Journal of Navigation     Hybrid Journal   (Followers: 90)
Journal of Sport & Social Issues     Hybrid Journal   (Followers: 9)
Journal of Sustainable Mobility     Full-text available via subscription  
Journal of the Transportation Research Forum     Open Access   (Followers: 4)
Journal of Traffic and Transportation Engineering (English Edition)     Open Access  
Journal of Transport & Health     Hybrid Journal   (Followers: 3)
Journal of Transport and Land Use     Open Access   (Followers: 13)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 6)
Journal of Transport Geography     Hybrid Journal   (Followers: 17)
Journal of Transport History     Full-text available via subscription   (Followers: 11)
Journal of Transport Literature     Open Access  
Journal of Transportation Safety & Security     Hybrid Journal   (Followers: 9)
Journal of Transportation Security     Hybrid Journal   (Followers: 3)
Journal of Transportation Systems Engineering and Information Technology     Full-text available via subscription   (Followers: 15)
Journal of Transportation Technologies     Open Access   (Followers: 11)
Journal of Waterway Port Coastal and Ocean Engineering     Full-text available via subscription   (Followers: 7)
Les Dossiers du Grihl     Open Access  
Logistique & Management     Full-text available via subscription  
Mechatronics, Electrical Power, and Vehicular Technology     Open Access   (Followers: 1)
Mobility in History     Full-text available via subscription  
Modern Transportation     Open Access   (Followers: 2)
Nonlinear Dynamics     Hybrid Journal   (Followers: 5)
Open Journal of Safety Science and Technology     Open Access   (Followers: 5)
Pervasive and Mobile Computing     Hybrid Journal   (Followers: 9)
Proceedings of the Institution of Mechanical Engineers Part F: Journal of Rail and Rapid Transit     Hybrid Journal   (Followers: 7)
PS: Political Science & Politics     Full-text available via subscription   (Followers: 24)
Public Transport     Hybrid Journal   (Followers: 10)
Recherche Transports Sécurité     Hybrid Journal   (Followers: 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: 11)
Sport, Ethics and Philosophy     Hybrid Journal   (Followers: 2)
Streetnotes     Open Access   (Followers: 3)
Synthesis Lectures on Mobile and Pervasive Computing     Full-text available via subscription   (Followers: 2)
Tire Science and Technology     Full-text available via subscription   (Followers: 1)
Transactions on Transport Sciences     Open Access   (Followers: 4)
Transport     Hybrid Journal   (Followers: 8)
Transport and Telecommunication Journal     Open Access   (Followers: 2)
Transport in Porous Media     Hybrid Journal   (Followers: 1)
Transport Reviews: A Transnational Transdisciplinary Journal     Hybrid Journal   (Followers: 7)
Transportation     Hybrid Journal   (Followers: 20)
Transportation Geotechnics     Full-text available via subscription  
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 6)
Transportation Journal     Full-text available via subscription   (Followers: 5)
Transportation Letters : The International Journal of Transportation Research     Hybrid Journal  
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 26)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 24)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 16)
Transportation Research Procedia     Open Access  
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 32)
Transportation Science     Full-text available via subscription   (Followers: 14)
TRANSPORTES     Open Access   (Followers: 2)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 1)
Transportmetrica B : Transport Dynamics     Hybrid Journal  
Travel Behaviour and Society     Full-text available via subscription   (Followers: 1)
Travel Medicine and Infectious Disease     Hybrid Journal   (Followers: 1)
Urban, Planning and Transport Research     Open Access   (Followers: 3)
Vehicular Communications     Full-text available via subscription  
World Review of Intermodal Transportation Research     Hybrid Journal   (Followers: 3)
Транспортні системи та технології перевезень     Open Access  
Journal Cover   Transportation Research Part C: Emerging Technologies
  [SJR: 1.943]   [H-I: 55]   [16 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0968-090X
   Published by Elsevier Homepage  [2812 journals]
  • Simulation and optimization: A short review
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Michel Bierlaire
      This review discusses some issues related to the use of simulation in transportation analysis. Potential pitfalls are identified and discussed. An overview of some methods relevant to the use of an advanced simulation tool in an optimization context is also provided.


      PubDate: 2015-05-26T09:33:54Z
       
  • Editorial Board/Copyright Information
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55




      PubDate: 2015-05-26T09:33:54Z
       
  • Matthew memorial special issue (optimization) – Preface
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55




      PubDate: 2015-05-26T09:33:54Z
       
  • When is big data big enough? Implications of using GPS-based surveys
           for travel demand analysis
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Akshay Vij , K. Shankari
      A number of studies in the last decade have argued that Global Positioning Systems (GPS) based survey offer the potential to replace traditional travel diary surveys. GPS-based surveys impose lower respondent burden, offer greater spatiotemporal precision and incur fewer monetary costs. However, GPS-based surveys do not collect certain key inputs required for the estimation of travel demand models, such as the travel mode(s) taken or the trip purpose, relying instead on data-processing procedures to infer this information. This study assesses the impact that errors in inference can have on travel demand models estimated using data from GPS-based surveys and proposes ways in which these errors can be controlled for during both data collection and model estimation. We use simulated datasets to compare performance across different sample sizes, inference accuracies, model complexities and estimation methods. Findings from the simulated datasets are corroborated with real data collected from individuals living in the San Francisco Bay Area, United States. Results indicate that the benefits of using GPS-based surveys will vary significantly, depending upon the sample size of the data, the accuracy of the inference algorithm and the desired complexity of the travel demand model specification. In many cases, gains in the volume of data that can potentially be retrieved using GPS devices are found to be offset by the loss in quality caused by inaccuracies in inference. This study makes the argument that passively collected GPS-based surveys may never entirely replace surveys that require active interaction with study participants.


      PubDate: 2015-05-26T09:33:54Z
       
  • Modelling the adoption intention and installation choice of an automotive
           after-market mild-solar-hybridization kit
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Stefano de Luca , Roberta Di Pace , Vincenzo Marano
      Despite the recent commercial success of hybrid, plug-in hybrid and electric vehicles their market share is still insufficient to produce either a significant impact on energy consumption on a global basis or a profitable automotive segment. In this context, the possibility of upgrading conventional vehicles to hybrid electric vehicles is gaining increasing interest. To this aim this paper investigated and modelled the intention to install an after-market hybridization solar-kit (HySolarKit) in order to ascertain the main behavioural determinants of the choice process and set up an operational model with which to estimate the market potential of such technology. In particular, two behavioural stages of the choice process were analysed and modelled: (i) the intention to adopt the HySolarKit; (ii) the choice to install the HySolarKit. Both issues were addressed through ad hoc stated preference surveys carried out in two different Italian cities, and through the specification and the calibration of discrete choice models based on the behavioural paradigm of random utility theory. Different modelling solutions (homoscedastic and heteroscedastic) were compared in terms of goodness-of-fit and sensitivity to level-of-service attributes. The results showed the technological potential of the HySolarKit, and that both behavioural stages may be effectively modelled through random utility theory. Estimation results allowed an interpretation of the main determinants of the investigated phenomena, making it possible to quantify the potential effects and the concerns towards such a green solution, and making it possible to draw up operative marketing strategies. In particular, the intention to adopt the kit mainly depends on socio-economic factors as well as activity-related and attitudinal attributes, whereas the probability of installing the kit is greatly affected, to the same extent, by installation cost, the charging cost and the weekly mileage driven.


      PubDate: 2015-05-26T09:33:54Z
       
  • Optimization of traffic forecasting: Intelligent surrogate modeling
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Eleni I. Vlahogianni
      Transportation modelers are frequently faced with several optimization challenges related to model selection and parameter optimization for forecasting. The concept of surrogate modeling is discussed in order to tackle some limitations related to the practice of developing short-term forecasting algorithms. An automated meta-modeling technique is presented that uses heterogeneous information from multiple types of statistical and computationally intelligent models, along with multi-objective evolutionary strategies to optimize the model and parameter selection. A number of different models from the family of Support Vector Machines, Radial Base Functions and Neural Networks are jointly considered and optimized with the aim to improve the short-term predictability of travel speed. Results are presented and discussed in both a univariate and multivariate framework.


      PubDate: 2015-05-26T09:33:54Z
       
  • Network Signal Setting Design: Meta-heuristic optimisation methods
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Giulio E. Cantarella , Stefano de Luca , Roberta Di Pace , Silvio Memoli
      This paper aims to investigate the application of meta-heuristic optimisation methods to Network Signal Setting Design. The adopted approaches are (i) three step optimisation, in which first the stage matrix (stage composition and sequence), the green timings at each single junction are optimised, then the node offsets are computed in three successive steps; (ii) two step optimisation, in which the stage matrix is defined at a first step, then the green timings and the node offsets are computed at a second step. In both approaches the stage matrix optimisation is carried out through explicit complete enumeration. In the first approach multi-criteria optimisation is followed for single junction signal setting design (green timings), whilst the coordination (node offsets) is approached through mono-criterion optimisation, as well as for the synchronisation (green timings and offsets) in the second approach. A new traffic flow model mixing CTM and PDM has been applied. This model allows to explicitly represent horizontal queuing phenomena as well as dispersion along a link. Some meta-heuristic algorithms (i.e. Genetic Algorithms, Hill Climbing and Simulated Annealing) are investigated in order to solve the two problems. The proposed strategies are applied to two different layouts (a two junction arterial vs. a four junction network) and their effectiveness is evaluated by comparing the obtained results with those from benchmark approaches implementing mono-criterion optimisation only.


      PubDate: 2015-05-26T09:33:54Z
       
  • Multi-criteria optimization of traffic signals: Mobility, safety, and
           environment
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Aleksandar Stevanovic , Jelka Stevanovic , Jaehyun So , Marija Ostojic
      Two-dimensional multi-objective optimizations have been used for decades for the problems in traffic engineering although only few times so far in the optimization of signal timings. While the other engineering and science disciplines have utilized visualization of 3-dimensional Pareto fronts in the optimization studies, we have not seen many of those concepts applied to traffic signal optimization problems. To bridge the gap in the existing knowledge this study presents a methodology where 3-dimensional Pareto Fronts of signal timings, which are expressed through mobility, (surrogate) safety, and environmental factors, are optimized by use of an evolutionary algorithm. The study uses a segment of 5 signalized intersections in West Valley City, Utah, to test signal timings which provide a balance between mobility, safety and environment. In addition, a set of previous developed signal timing scenarios, including some of the Connected Vehicle technologies such as GLOSA, were conducted to evaluate the quality of the 3-dimensional Pareto front solutions. The results show success of 3-dimensinal Pareto fronts moving towards optimality. The resulting signal timing plans do not show large differences between themselves but all improve on the signal timings from the field, significantly. The commonly used optimization of standard single-objective functions shows robust solutions. The new set of Connected Vehicle technologies also shows promising benefits, especially in the area of reducing inter-vehicular friction. The resulting timing plans from two optimization sets (constrained and unconstrained) show that environmental and safe signal timings coincide but somewhat contradict mobility. Further research is needed to apply similar concepts on a variety of networks and traffic conditions before generalizing findings.


      PubDate: 2015-05-26T09:33:54Z
       
  • Optimisation of dynamic motorway traffic via a parsimonious and
           decentralised approach
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Andy H.F. Chow
      This paper presents an optimisation framework for motorway management via ramp metering and variable speed limit. We start with presenting a centralised global optimal control problem aiming to minimise the total travel delay in a motorway system. Given the centralised global optimal control solutions, we propose a set of decentralised ramp metering and speed control strategies which operate on a novel parsimonious dynamic platform without needing an underlying traffic model. The control strategies are applied to a case on UK M25 motorway. The results show that the proposed set of decentralised control is able to deliver a performance that is close to the global optimal ones with significantly less computational and implementation effort. This study provides new insights to motorway management.


      PubDate: 2015-05-26T09:33:54Z
       
  • Two-class freeway traffic regulation to reduce congestion and emissions
           via nonlinear optimal control
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Cecilia Pasquale , Ioannis Papamichail , Claudio Roncoli , Simona Sacone , Silvia Siri , Markos Papageorgiou
      The objective of this paper is the regulation of freeway traffic by means of optimal control techniques. A first innovative aspect of the proposed approach is the adopted objective function in which, besides the reduction of traffic congestion (which is typically considered in traffic control schemes), the minimization of traffic emissions is also included. Moreover, a multi-class framework is defined in which two classes of vehicles (cars and trucks) are explicitly modelled, and specific control actions for each vehicle class are sought. This results in the formulation of a multi-objective optimal control problem which is described in the paper and for which a specific solution algorithm is developed and used. The algorithm exploits a specific version of the feasible direction algorithm whose effectiveness is demonstrated in the paper by means of simulation results.


      PubDate: 2015-05-26T09:33:54Z
       
  • Optimization-based assisted calibration of traffic simulation models
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): David K. Hale , Constantinos Antoniou , Mark Brackstone , Dimitra Michalaka , Ana T. Moreno , Kavita Parikh
      Use of traffic simulation has increased in recent decades; and this high-fidelity modelling, along with moving vehicle animation, has allowed transportation decisions to be made with better confidence. During this time, traffic engineers have been encouraged to embrace the process of calibration, in which steps are taken to reconcile simulated and field-observed performance. According to international surveys, experts, and conventional wisdom, existing (non-automated) methods of calibration have been difficult or inadequate. There has been extensive research on improved calibration methods, but many of these efforts have not produced the flexibility and practicality required by real-world engineers. With this in mind, a patent-pending (US 61/859,819) architecture for software-assisted calibration was developed to maximize practicality, flexibility, and ease-of-use. This architecture is called SASCO (i.e. Sensitivity Analysis, Self-Calibration, and Optimization). The original optimization method within SASCO was based on “directed brute force” (DBF) searching; performing exhaustive evaluation of alternatives in a discrete, user-defined search space. Simultaneous Perturbation Stochastic Approximation (SPSA) has also gained favor as an efficient method for optimizing computationally expensive, “black-box” traffic simulations, and was also implemented within SASCO. This paper uses synthetic and real-world case studies to assess the qualities of DBF and SPSA, so they can be applied in the right situations. SPSA was found to be the fastest method, which is important when calibrating numerous inputs, but DBF was more reliable. Additionally DBF was better than SPSA for sensitivity analysis, and for calibrating complex inputs. Regardless of which optimization method is selected, the SASCO architecture appears to offer a new and practice-ready level of calibration efficiency.


      PubDate: 2015-05-26T09:33:54Z
       
  • Weather impact on containership routing in closed seas: A
           chance-constraint optimization approach
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Konstantinos Kepaptsoglou , Grigorios Fountas , Matthew G. Karlaftis
      Weather conditions have a strong effect on the operation of vessels and unavoidably influence total time at sea and associated transportation costs. The velocity and direction of the wind in particular may considerably affect travel speed of vessels and therefore the reliability of scheduled maritime services. This paper considers weather effects in containership routing; a stochastic model is developed for determining optimal routes for a homogeneous fleet performing pick-ups and deliveries of containers between a hub and several spoke ports, while incorporating travel time uncertainties attributed to the weather. The problem is originally formulated as a chance-constrained variant of the vehicle routing problem with simultaneous pick-ups and deliveries and time constraints and solved using a genetic algorithm. The model is implemented to a network of island ports of the Aegean Sea. Results on the application of algorithm reveal that a small fleet is sufficient enough to serve network’s islands, under the influence of minor delays. A sensitivity analysis based on alternative scenarios in the problem’s parameters, leads to encouraging conclusions with respect to the efficiency and robustness of the algorithm.


      PubDate: 2015-05-26T09:33:54Z
       
  • Optimizing dial-a-ride services in Maryland: Benefits of computerized
           routing and scheduling
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Nikola Marković , Rahul Nair , Paul Schonfeld , Elise Miller-Hooks , Matthew Mohebbi
      This paper reports on a system developed to address the dial-a-ride problem and an implementation for Maryland where real-world practical constraints are considered in providing customized vehicle routing and scheduling for about 450 trip requests daily. The system, called Mobile Resource Management System (MRMS), allows for dispatch operators to quickly study different operational scenarios and, in a strategic setting, explore tradeoffs between level-of-service and various system characteristics, including fleet composition, fleet size and dispatch rules. Such insights play a key role in making long-term investment decisions or estimating cost of servicing contracts that have service level agreements. Test comparison of manual and MRMS-based routes indicated an estimated annual operational expense reduction of $0.82 million, or about 18% of the total annual expense. In addition to the cost benefits, improved quality of service and the reduction in total vehicle-kilometers traveled leading to environmental benefits are demonstrated.


      PubDate: 2015-05-26T09:33:54Z
       
  • A reliability-based optimization scheme for maintenance management in
           large-scale bridge networks
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Xiaofei Hu , Carlos Daganzo , Samer Madanat
      Incorporating network configurations in bridge management problems is computationally difficult. Because of the interdependencies among bridges in a network, they have to be analyzed together. Simulation-based numerical optimization techniques adopted in past research are limited to networks of moderate sizes. In this paper, a simple framework is developed to determine optimal maintenance plans for large networks with many bridges. The objective is to minimize disruption, specifically, the extra travel distance caused by potential bridge failures over a planning horizon and under a budget constraint. It is conjectured and then verified that the expected increase in vehicle-miles traveled due to failures can be approximated by the sum of expected increases due to individual failures. This allows the network-level problem to be decomposed into single-bridge problems and tackled efficiently. The computational effort increases linearly with the number of bridges.


      PubDate: 2015-05-26T09:33:54Z
       
  • An optimization method for sustainable traffic control in urban areas
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Eleni Papatzikou , Antony Stathopoulos
      The optimization of traffic signalization in urban areas is formulated as a problem of finding the cycle length, the green times and the offset of traffic signals that minimize an objective function of performance indices. Typical approaches to this optimization problem include the maximization of traffic throughput or the minimization of vehicles’ delays, number of stops, fuel consumption, etc. Dynamic Traffic Assignment (DTA) models are widely used for online and offline applications for efficient deployment of traffic control strategies and the evaluation of traffic management schemes and policies. We propose an optimization method for combining dynamic traffic assignment and network control by minimizing the risk of potential loss induced to travelers by exceeding their budgeted travel time as a result of deployed traffic signal settings, using the Conditional Value-at-Risk model. The proposed methodology can be easily implemented by researchers or practitioners to evaluate their alternative strategies and aid them to choose the alternative with less potential risk. The traffic signal optimization procedure is implemented in TRANSYT-7F and the dynamic propagation and route choice of vehicles is simulated with a mesoscopic dynamic traffic assignment tool (DTALite) with fixed temporal demand and network characteristics. The proposed approach is applied to a reference test network used by many researchers for verification purposes. Numerical experiments provide evidence of the advantages of this optimization method with respect to conventional optimization techniques. The overall benefit to the performance of the network is evaluated with a Conditional Value-at-Risk Analysis where the optimal solution is the one presenting the least risk for ‘guaranteed’ total travel times.


      PubDate: 2015-05-26T09:33:54Z
       
  • Optimality versus run time for isolated signalized intersections
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): David K. Hale , Byungkyu Brian Park , Aleksandar Stevanovic , Peng Su , Jiaqi Ma
      Simulation-based optimization of traffic signal timing has become pervasive and popular, in the field of traffic engineering. When the underlying simulation model is well-trusted and/or well-calibrated, it is only natural that typical engineers would want their signal timing optimized using the judgment of that same model. As such, it becomes important that the heuristic search methods typically used by these optimizations are capable of locating global optimum solutions, for a wide range of signal systems. However off-line and real-time solutions alike offer just a subset of the available search methods. The result is that many optimizations are likely converging prematurely on mediocre solutions. In response, this paper compares several search methods from the literature, in terms of both optimality (i.e., solution quality) and computer run times. Simulated annealing and genetic algorithm methods were equally effective in achieving near-global optimum solutions. Two selection methods (roulette wheel and tournament), commonly used within genetic algorithms, exhibited similar effectiveness. Tabu searching did not provide significant benefits. Trajectories of optimality versus run time (OVERT) were similar for each method, except some methods aborted early along the same trajectory. Hill-climbing searches always aborted early, even with a large number of step-sizes. Other methods only aborted early when applied with ineffective parameter settings (e.g. mutation rate, annealing schedule). These findings imply (1) today’s products encourage a sub-optimal “one size fits all” approach, (2) heuristic search methods and parameters should be carefully selected based on the system being optimized, (3) weaker searches abort early along the OVERT curve, and (4) improper choice of methods and/or parameters can reduce optimization benefits by 22–33%.


      PubDate: 2015-05-26T09:33:54Z
       
  • Optimal number and location of Bluetooth sensors considering stochastic
           travel time prediction
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Hyoshin Park , Ali Haghani
      Determining the optimal number and location of sensors is essential to effectively manage traffic on highways. Optimal solutions dealing with dynamic traffic patterns and relocation of sensors have received little attention. In this study, existing fixed sensors are used to estimate travel time prediction errors at candidate locations where we deploy portable sensors. Potential sampling error of each candidate location is also counted in selecting optimal locations. A two-stage stochastic formulation considers uncertainty of traffic conditions based on scenarios generated by principal component analysis and clustering analysis to uncover the underlying spatial correlations and temporal patterns. The first stage decision, determining the optimal number of sensors, is made before the deployment. The second stage, evaluating the expected travel time prediction errors, specifies sensor arrangements in each scenario. A dynamic model has predefined rearrangement stages. At each stage, sensor locations are modified as the pattern of travel time error changes over time, considering sensor acquisition and relocation expenses. The deterministic and stochastic solutions serve as a lower bound and an upper bound for the dynamic solution. Higher relocation expense leads to more sensors being used, while higher sensor costs leads to fewer sensors being used with more frequent relocations.


      PubDate: 2015-05-26T09:33:54Z
       
  • Sensor location problems in path-differentiated congestion pricing
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Mahmood Zangui , Yafeng Yin , Siriphong Lawphongpanich
      Path-differentiated congestion pricing is a tolling scheme that imposes tolls on paths instead of individual links. One way to implement this scheme is to deploy automated vehicle identification sensors, such as toll tag readers or license plate scanners, on roads in a network. These sensors collect vehicles’ location information to identify their paths and charge them accordingly. In this paper, we investigate how to optimally locate these sensors for the purpose of implementing path-differentiated pricing. We consider three relevant problems. The first is to locate a minimum number of sensors to implement a given path-differentiated scheme. The second is to design an optimal path-differentiated pricing scheme for a given set of sensors. The last problem is to find a path differentiated scheme to induce a given target link-flow distribution while requiring a minimum number of sensors.


      PubDate: 2015-05-26T09:33:54Z
       
  • c-SPSA: Cluster-wise simultaneous perturbation stochastic approximation
           algorithm and its application to dynamic origin–destination matrix
           estimation
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Athina Tympakianaki , Haris N. Koutsopoulos , Erik Jenelius
      The simultaneous perturbation stochastic approximation (SPSA) algorithm has been used in the literature for the solution of the dynamic origin–destination (OD) estimation problem. Its main advantage is that it allows quite general formulations of the problem that can include a wide range of sensor measurements. While SPSA is relatively simple to implement, its performance depends on a set of parameters that need to be properly determined. As a result, especially in cases where the gradient of the objective function changes quickly, SPSA may not be as stable and even diverge. A modification of the SPSA algorithm, referred to as c-SPSA, is proposed which applies the simultaneous perturbation approximation of the gradient within a small number of carefully constructed “homogeneous” clusters one at a time, as opposed to all elements at once. The paper establishes the theoretical properties of the new algorithm with an upper bound for the bias of the gradient estimate and shows that it is lower than the corresponding SPSA bias. It also proposes a systematic approach, based on the k-means algorithm, to identify appropriate clusters. The performance of c-SPSA, with alternative implementation strategies, is evaluated in the context of estimating OD flows in an actual urban network. The results demonstrate the efficiency of the proposed c-SPSA algorithm in finding better OD estimates and achieve faster convergence and more robust performance compared to SPSA with fewer overall number of function evaluations.


      PubDate: 2015-05-26T09:33:54Z
       
  • Transit stop inspection and maintenance scheduling: A GPU accelerated
           metaheuristics approach
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Nikolaos Ath. Kallioras , Konstantinos Kepaptsoglou , Nikos D. Lagaros
      Bus stops are integral elements of a transit system and as such, their efficient inspection and maintenance is required, for proper and attractive transit operations. Nevertheless, spatial dispersion and the extensive number of bus stops, even for mid-size transit systems, complicates scheduling of inspection and maintenance tasks. In this context, the problem of scheduling transit stop inspection and maintenance activities (TSIMP) by a two-stage optimization approach, is formulated and discussed. In particular, the first stage involves districting of the bus stop locations into areas of responsibility for different inspection and maintenance crews (IMCs), while in the second stage, determination of the sequence of bus stops to be visited by an IMC is modelled as a vehicle routing problem. Given the complexity of proposed optimization models, advanced versions of different metaheuristic algorithms (Harmony Search and Ant Colony Optimization) are exploited and assessed as possible options for solving these models. Furthermore, two variants of ACO are implemented herein; one implemented into a CPU parallel computing environment along with an accelerated one by means of general-purpose graphics processing unit (GPGPU) computing. The model and algorithms are applied to the Athens (Greece) bus system, whose extensive number of transit stops (over 7500) offers a real-world test bed for assessing the potential of the proposed modelling approach and solution algorithms. As it was shown for the test example examined, both algorithms managed to achieve optimized solutions for the problem at hand while there were fund robust with respect to their algorithmic parameters. Furthermore, the use of graphics processing units (GPU) managed to reduce of computational time required.


      PubDate: 2015-05-26T09:33:54Z
       
  • Generalized Maximum Benefit Multiple Chinese Postman Problem
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Ali Shafahi , Ali Haghani
      This research is focused on a generalization on the Max Benefit Chinese Postman Problem and the multiple vehicle variant of the Chinese Postman Problem. We call this generalization, the Generalized Maximum Benefit k-Chinese Postman Problem (GB k-CPP). We present a novel Mixed Integer Programming (MIP) formulation for the GB k-CPP. Four different cases of the model are discussed. The first case, performs arc-routing with profits and assumes that the origin and destination for each vehicle is the same for each cycle and is given by the user. The next case relaxes the assumption that the origin and destination for each vehicle should be the same and allows the users to select possible origins/destinations for vehicles. Case three gets the origin for each vehicle as input and produces a solution based on finding the best destination for each vehicle. The last case, that is very general, allows the optimization model to select possibly different locations for vehicle origin and destination, during each cycle. The different cases are applied to a security patrolling case conducted on the network of University of Maryland at College Park campus and the results are compared.


      PubDate: 2015-05-26T09:33:54Z
       
  • A dynamic closed-loop vehicle routing problem with uncertainty and
           incompatible goods
    • Abstract: Publication date: June 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 55
      Author(s): Zhi-Hua Hu , Jiuh-Biing Sheu , Lei Zhao , Chung-Cheng Lu
      This study investigates a dynamic closed-loop vehicle routing problem (VRP) with uncertain pickup and deterministic delivery of incompatible goods, which is an extension of the VRP with simultaneous pickup and delivery (VRPSPD) in closed-loop logistics, where the incompatibility between goods of pickup and delivery is considered. The problem involves minimizing transportation cost, incompatibility and number of customers visited twice. A solution method based on variable neighborhood search (VNS) is developed for solving the VRPSPD. The pickup uncertainty is handled in two stages: first, a priori routes are generated by solving a VRPSPD whose pickup demands are estimated; second, the a priori routes are simulated by dynamically satisfying the pickup demand under incompatibility, and the second-round routes are generated to meet the unmet demands. The effects of considering the incompatibility are examined by experiments. A case of centralized tableware disinfection and logistics services in China’s catering industry is used for demonstration. Disinfected tableware for delivery and used tableware for pickup are incompatible because of potential cross-contamination. The experimental results quantitatively provide insights for managers who must solve the dynamic closed-loop VRP with uncertain pickup and incompatible goods. The proposed method also proves competitive for the VRPSPD.


      PubDate: 2015-05-26T09:33:54Z
       
  • The concept and impact analysis of a flexible mobility on demand system
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Bilge Atasoy , Takuro Ikeda , Xiang Song , Moshe E. Ben-Akiva
      This paper introduces an innovative transportation concept called Flexible Mobility on Demand (FMOD), which provides personalized services to passengers. FMOD is a demand responsive system in which a list of travel options is provided in real-time to each passenger request. The system provides passengers with flexibility to choose from a menu that is optimized in an assortment optimization framework. For operators, there is flexibility in terms of vehicle allocation to different service types: taxi, shared-taxi and mini-bus. The allocation of the available fleet to these three services is carried out dynamically so that vehicles can change roles during the day. The FMOD system is built based on a choice model and consumer surplus is taken into account in order to improve passenger satisfaction. Furthermore, profits of the operators are expected to increase since the system adapts to changing demand patterns. In this paper, we introduce the concept of FMOD and present preliminary simulation results. It is shown that the dynamic allocation of the vehicles to different services provides significant benefits over static allocation. Furthermore, it is observed that the trade-off between consumer surplus and operator’s profit is critical. The optimization model is adapted in order to take into account this trade-off by controlling the level of passenger satisfaction. It is shown that with such control mechanisms FMOD provides improved results in terms of both profit and consumer surplus.


      PubDate: 2015-05-21T09:27:42Z
       
  • A novel three-step procedure to forecast the inspection volume
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): J.J. Ruiz-Aguilar , I.J. Turias , M.J. Jiménez-Come
      The inspection process of freight traffic at Border Inspection Posts (BIPs) generates significant time delays and congestion within the transport system. The use of forecasting methods to anticipate these situations could be a good solution. Traditional methodologies for time series prediction usually consist on: applying single techniques, combining these techniques with some others such as clustering techniques or hybridizing single prediction techniques. A novel methodology based on a three-step procedure is proposed in this paper in order to better predict the number of inspections at BIPs, integrating a clustering technique and a hybrid prediction model. Specifically, the seasonal auto-regressive integrated moving averages (SARIMA) is used first to predict the data. Then, self-organizing maps (SOM) decomposes the time series into smaller regions with similar statistical properties. Finally, Artificial Neural Networks (ANNs) are applied in each homogeneous regions to forecast the inspections volume, testing different hybrid approaches based on the inputs of the model. The experimental results show that the performance of inspection prediction can be enhanced by using the novel three-stage procedure, providing relevant information for resource planning and turning into a powerful decision-making tool, not only at the inspection process of seaports or airports, but also in the field of time series prediction.
      Graphical abstract image

      PubDate: 2015-05-21T09:27:42Z
       
  • How comfortable are your cycling tracks? A new method for objective
           bicycle vibration measurement
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Michal Bíl , Richard Andrášik , Jan Kubeček
      Cycling comfort consists of several factors. Their relevant values are important in the process of bicycle facility planning. Poor surface pavement quality manifests itself in terms of vibrations of a bicycle. This strongly influences the perception of a cycle track, general cycling comfort and the route choice as well. We introduce dynamic comfort index (DCI) which is capable of objectively describing the vibration properties of surface pavement on a track. The DCI is derived from data gathered when riding a bicycle equipped with a GPS device and an accelerometer. The most common types of devices were selected to make the DCI widely applicable. We tested DCI values on various bicycles and surface pavements. DCI values on individual cycling tracks were compared with the subjective feelings of 43 cyclists via questionnaires. A strong correlation (−0.94) was obtained between the objectively measured DCI values and the subjectively assessed evaluations. This makes the DCI approach transferable to any other environment. This method has been applied to an entire road network within the historical center of the city of Olomouc (Czech Republic). It can further be used by bicycle track administrators to monitor surface quality, by planners to obtain relevant surface pavement values, and by individual cyclists for optimal route choice.


      PubDate: 2015-05-21T09:27:42Z
       
  • The fleet renewal problem with regional emission limitations: Case study
           from Roll-on/Roll-off shipping
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Øyvind S. Patricksson , Kjetil Fagerholt , Jørgen G. Rakke
      In this paper, the maritime fleet renewal problem (MFRP) is extended to include regional limitations in the form of emission control areas. The motivation for including this aspect is that strengthening of emission regulations in such areas is expected to be challenging for deep sea shipping in the years to come. In the proposed model, various means to cope with these stricter emission regulations are evaluated for new vessels, and the possibility of upgrading existing vessels with new emission reduction technology is introduced. We consider future fuel prices to be important for the problem, and have chosen to treat them as uncertain, and thus, a stochastic programming model is chosen. A fleet renewal problem faced by the liner shipping operator Wallenius Wilhelmsen Logistics, concerning whether to use low sulphur fuel or have an exhaust gas scrubber system installed to comply with sulphur regulation in emission control areas from 2015, is used as a case study. Furthermore, tests show that the savings from including the aspect of emission control areas in the MFRP are substantial.


      PubDate: 2015-05-21T09:27:42Z
       
  • Assessing the viability of enabling a round-trip carsharing system to
           accept one-way trips: Application to Logan Airport in Boston
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Diana Jorge , Cynthia Barnhart , Gonçalo Homem de Almeida Correia
      Although one-way carsharing is suitable for more trip purposes than round-trip carsharing, many companies in the world operate only in the round-trip market. In this paper, we develop a method that optimizes the design of a one-way carsharing service between selected origin–destination pairs of an existing round-trip carsharing system. The goal is to supplement the established round-trip services with new one-way services and increase profitability. We develop an integer programming model to select the set of new one-way services and apply it to the case study of Boston, USA, considering only trips with one endpoint at a station in the round-trip Zipcar service network and the other endpoint at Logan Airport. The airport was chosen as a necessary endpoint for a one-way service because it is a very significant trip generator for which the round-trip carsharing is not suitable. Results show that these supplemental one-way services could be profitable. Enabling relocation operations between the existing round-trip stations and the Airport greatly improves the demand effectively satisfied, leads to an acceptable airport station size (in terms of the number of parking spots required), and is profitable; however, these benefits come with the need to manage relocation operations.


      PubDate: 2015-05-21T09:27:42Z
       
  • Optimal competitive freight network design as hierarchical variational
           inequalities programming problems
    • Abstract: Publication date: Available online 13 May 2015
      Source:Transportation Research Part C: Emerging Technologies
      Author(s): Loukas Dimitriou
      Freight networks are a case of systems that multiple participants are composing interrelations along the complete supply chain. Their interrelations correspond to alternative behavior, namely, cooperation, non-cooperation and competition, while they are large-scale spatially distributed systems combining multiple means of transportation and the infrastructure and equipment typically utilized for servicing demand, results to a complex system integration. In this paper, the case of the optimal design of freight networks is investigated, aiming to highlight the particularities emerging in this case of transportation facilities strategic and/or operational planning and the multiple game-theoretic and equilibrium problems that are structured in cascade and in hierarchies. The application that is investigated here focuses in the design of a significant ‘player’ of the freight supply chain, namely container terminals, while the proposed framework will aim on analyzing investment strategies built on integrated demand–supply models and the optimal network design format. The approach will build on the multilevel Mathematical Programming with Equilibrium Constraints (MPECs) formulation, but is further extended to cope with the properties introduced by the ‘designers’ (infrastructure authorities), shippers and carriers competition in all levels of MPECs. Since container terminals are typically competing each other, the nomenclature used here for formulating appropriate MPECs problems are based on hierarchies of Variational Inequalities (VI) problems, able to capture the alternative relationships emerging in realistic freight supply chains. The proposed formulations of the competitive network design case is addressed by a novel approach of co-evolutionary agents, which can be regarded as new in equilibrium estimation. Finally, the results are compared with alternative network design cases, namely the centralized cooperative and exchanging design. Under this analysis it is able to highlight the differences among alternative design cases, but moreover an estimation of the ‘price of anarchy’ in transportation systems design is offered, an element of both theoretical as well as practical relevance.


      PubDate: 2015-05-17T09:24:12Z
       
  • Flow-based accessibility measurement: The Place Rank approach
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Guihua Wang , Yuanguang Zhong , Chung-Piaw Teo , Qizhang Liu
      In this paper, we empirically test the viability of a flow-based approach as an alternative to transport accessibility measurement. To track where commuters travel from and to (but not commute times), we use transactional smartcard data from residents in Singapore to construct the (daily) spatial network of trips generated. We use the Place Rank method to demonstrate the viability of the flow-based approach to study accessibility. We compute the Place Rank of each of 44 planning areas in Singapore. Interestingly, even though the spatial network is constructed using only origin–destination information, we find that the travel time of the trips out of each planning area generally decreases as the area’s Place Rank increases. The same is also the case for in-vehicle time, number of transfers in the network and transfer time. This shows that a flow-based approach can be used to measure the notion of accessibility, which is traditionally assessed using travel time information in the system. We also compare Place Rank with other indicators, namely, bus stop density, eigenvector centrality, clustering coefficient and typographical coefficient to evaluate an area’s accessibility. The results show that these indicators are not as effective as the Place Rank method.


      PubDate: 2015-05-07T22:56:08Z
       
  • Efficiency of a highway use reservation system for morning commute
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Wei Liu , Hai Yang , Yafeng Yin
      This paper examines the design and efficiency of a highway use reservation system where commuters need reservations to access a highway facility at specific times. We show that, by accommodating reservation requests to the level that the highway capacity allows, traffic congestion can be relieved. Generally, a more differentiated design of the reservation system yields a higher reduction of travel cost and thus achieves a higher efficiency. The efficiency bound of the system is established. We also show that braking or tactical waiting behaviors of drivers would cause a loss of efficiency, which thus need be proactively accommodated. Given that user heterogeneity cause further loss of efficiency, we explore how two specific types of user heterogeneity affect the system efficiency. Auction-based reservation is then proposed to mitigate the efficiency loss.


      PubDate: 2015-05-04T08:16:09Z
       
  • Application of Lagrangian relaxation approach to α-reliable path
           finding in stochastic networks with correlated link travel times
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Weiliang Zeng , Tomio Miwa , Yukiko Wakita , Takayuki Morikawa
      This study investigates the important problem of determining a reliable path in a stochastic network with correlated link travel times. First, the distribution of path travel time is quantified by using trip records from GPS probe vehicles. Second, the spatial correlation of link travel time is explicitly considered by using a correlation coefficient matrix, which is incorporated into the α-reliable path problem by Cholesky decomposition. Third, the Lagrangian relaxation based framework is used to handle the α-reliable path problem, by which the intractable problem with a non-linear and non-additive structure can be decomposed into several easy-to-solve problems. Finally, the path-finding performance of this approach is tested on a real-world network. The results show that 15 iterations of calculation can yield a small relative gap between upper and lower bounds of the optimal solution and the average running time is about 5s for most OD settings. The applicability of α-reliable path finding is validated by a case study.
      Graphical abstract image

      PubDate: 2015-05-04T08:16:09Z
       
  • Air cargo operations: Literature review and comparison with practices
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Bo Feng , Yanzhi Li , Zuo-Jun Max Shen
      This study reviews the literature on air cargo operations and compares theoretical studies with the practical problems of airlines, freight forwarders, and terminal service providers. In particular, we review studies in which mathematical models were used to identify the essential characteristics of air cargo operations, such as the intrinsic differences from passenger operations, and to explore the service processes in air cargo operations. The typical models used in previous studies are summarized. We then highlight the insightful findings from an industrial interview and present the gaps between previous research and practical realities. We finally discuss the new research opportunities of air cargo operations according to the gaps.


      PubDate: 2015-04-29T11:00:38Z
       
  • Coordinated cruise control for high-speed train movements based on a
           multi-agent model
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Shukai Li , Lixing Yang , Ziyou Gao
      This paper investigates the coordinated cruise control strategy for multiple high-speed trains’ movement. The motion of an ordered set of high-speed trains running on a railway line is modeled by a multi-agent system, in which each train communicates with its neighboring trains to adjust its speed. By using the potential fields and LaSalles invariance principle, we design a new coordinated cruise control strategy for each train based on the neighboring trains’ information, under which each train can track the desired speed, and the headway distances between any two neighboring trains are stabilized in a safety range. Numerical examples are given to illustrate the effectiveness of the proposed methods.


      PubDate: 2015-04-29T11:00:38Z
       
  • Automated classification based on video data at intersections with heavy
           pedestrian and bicycle traffic: Methodology and application
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Sohail Zangenehpour , Luis F. Miranda-Moreno , Nicolas Saunier
      Pedestrians and cyclists are amongst the most vulnerable road users. Pedestrian and cyclist collisions involving motor-vehicles result in high injury and fatality rates for these two modes. Data for pedestrian and cyclist activity at intersections such as volumes, speeds, and space–time trajectories are essential in the field of transportation in general, and road safety in particular. However, automated data collection for these two road user types remains a challenge. Due to the constant change of orientation and appearance of pedestrians and cyclists, detecting and tracking them using video sensors is a difficult task. This is perhaps one of the main reasons why automated data collection methods are more advanced for motorized traffic. This paper presents a method based on Histogram of Oriented Gradients to extract features of an image box containing the tracked object and Support Vector Machine to classify moving objects in crowded traffic scenes. Moving objects are classified into three categories: pedestrians, cyclists, and motor vehicles. The proposed methodology is composed of three steps: (i) detecting and tracking each moving object in video data, (ii) classifying each object according to its appearance in each frame, and (iii) computing the probability of belonging to each class based on both object appearance and speed. For the last step, Bayes’ rule is used to fuse appearance and speed in order to predict the object class. Using video datasets collected in different intersections, the methodology was built and tested. The developed methodology achieved an overall classification accuracy of greater than 88%. However, the classification accuracy varies across modes and is highest for vehicles and lower for pedestrians and cyclists. The applicability of the proposed methodology is illustrated using a simple case study to analyze cyclist–vehicle conflicts at intersections with and without bicycle facilities.


      PubDate: 2015-04-24T18:38:57Z
       
  • Highway voting system: Embracing a possible paradigm shift in traffic data
           acquisition
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Wei-Hua Lin , Hong K. Lo
      The integration of internet and mobile phones has opened the door to a new wave of utilizing private vehicles as probes not only for performance evaluation but for traffic control as well, gradually replacing the role of traffic surveillance systems as the dominant source of traffic data. To prepare for such a paradigm shift, one needs to overcome some key institutional barriers, in particular, the privacy issue. A Highway Voting System (HVS) is proposed to address this issue in which drivers provide link- and/or path-based vehicle data to the traffic management system in the form of “votes” in order to receive favorable service from traffic control. The proposed HVS offers a platform that links data from individual vehicles directly with traffic control. In the system, traffic control responds to voting vehicles in a way similar to the current system responding to prioritized vehicles and providing the requested services accordingly. We show in the paper that the proposed “voting” system can effectively resolve the privacy issue which often hampers traffic engineers from getting detailed data from drivers. Strategies to entice drivers into “voting” so as to increase the market penetration level under all traffic conditions are discussed. Though the focus of the paper is on addressing the institutional issues associated with data acquisition from individual vehicles, other research topics associated with the proposed system are identified. Two examples are given to demonstrate the impact of the proposed system on algorithm development and traffic control.


      PubDate: 2015-04-24T18:38:57Z
       
  • Location privacy preferences: A survey-based analysis of consumer
           awareness, trade-off and decision-making
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Caitlin D. Cottrill , Piyushimita “Vonu” Thakuriah
      With the advent and rapid dissemination of location-sensing information technology, the issue of location information privacy is receiving growing attention. Perhaps of greatest concern is ensuring that potential users of mobile Information and Communications Technologies (e.g., Location-Based Services and Intelligent Transportation Systems) are comfortable with the levels of privacy protection afforded them, as well as with the benefits they will receive in return for providing private location information. This paper explores the concepts of privacy risks, benefits, willingness to trade, and compensation in relationship to mobile and locational technologies using a stated preference survey to ascertain areas of interest in determining the trade-offs that consumers will be willing to make in return for mobility enhancements. Analysis of the survey leads to findings that while respondents believe that sharing data in the mobile environment may pose privacy risks, they do not generally take steps necessary to address these risks; that privacy preferences are impacted by a range of factors, including both personal and contextual considerations (such as factors arising from their specific situation at the time of information seeking); and that willingness to trade private location data is dependent upon a number of factors related to context, personal characteristics, expected benefits and degree of trust in the collecting organization.


      PubDate: 2015-04-24T18:38:57Z
       
  • Orchestration of driving simulator scenarios based on dynamic actor
           preparation and automated action planning
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Zhitao Xiong , Johan Olstam
      In driving simulation, a scenario includes definitions of the road environment, the traffic situation, simulated vehicles’ interactions with the participant’s vehicle and measurements that need to be collected. The scenarios need to be designed in such a way that the research questions to be studied can be answered, which commonly imply exposing the participant for a couple of predefined specific situations that has to be both realistic and repeatable. This article presents an integrated algorithm based on Dynamic Actor Preparation and Automated Action Planning to control autonomous simulated vehicles in the simulation in order to generate predefined situations. This algorithm is thus able to plan driving actions for autonomous vehicles based on specific tasks with relevant contextual information as well as handling longitudinal transportation of simulated vehicles based on the contextual information in an automated manner. The conducted experiment shows that the algorithm is able to guarantee repeatability under autonomous traffic flow. The presented algorithm can benefit not only the driving simulation community, but also relevant areas, such as autonomous vehicle and in-vehicle device design by providing them with an algorithm for target pursue and driving task accomplishment, which can be used to design a human-vehicle cooperation system in the coming era of autonomous driving.


      PubDate: 2015-04-24T18:38:57Z
       
  • Effect of speed limits in degradable transport networks
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Chen-Yang Yan , Rui Jiang , Zi-You Gao , Hu Shao
      This paper studies how link-specific speed limits influence the performance of degradable transport networks, in which the capacity of each link is a degradable random variable. The distribution and cumulative distribution of link travel time have been presented with the effect of speed limits taken into account. The mean and variance of link and route travel time are formulated. Three link states have been classified, and their physical meanings have been discussed. The relationship between critical capacity, travel time and speed limit has been elaborated. We have proposed a Speed Limit- and Reliability-based User Equilibrium (SLRUE), adopting travel time budget as the principle of travelers’ route choice. A heuristic method employing the method of successive averages is developed to solve the SLRUE in degradable networks. Through numerical studies, we find that for some networks both the mean and standard deviation of the total travel time could be reduced simultaneously by imposing some speed limits. The speed limit design problem has been studied, and it is found that imposing speed limits cannot always reduce the total travel time budget of a network.


      PubDate: 2015-04-24T18:38:57Z
       
  • Vehicle detection grammars with partial occlusion handling for traffic
           surveillance
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Bin Tian , Ming Tang , Fei-Yue Wang
      Traffic surveillance is an important topic in intelligent transportation systems (ITS). Robust vehicle detection is one challenging problem for complex traffic surveillance. In this paper, we propose an efficient vehicle detection method by designing vehicle detection grammars and handling partial occlusion. The grammar model is implemented by novel detection grammars, including structure, deformation and pairwise SVM grammars. First, the vehicle is divided into its constitute parts, called semantic parts, which can represent the vehicle effectively. To increase the robustness of part detection, the semantic parts are represented by their detection score maps. The semantic parts are further divided into sub-parts automatically. The two-layer division of the vehicle is modeled into a grammar model. Then, the grammar model is trained by a designed training procedure to get ideal grammar parameters, including appearance models and grammar productions. After that, vehicle detection is executed by a designed detection procedure with respect to the grammar model. Finally, the issue of vehicle occlusion is handled by designing and training specific grammars. The strategy adopted by our method is first to divide the vehicle into the semantic parts and sub-parts, then to train the grammar productions for semantic parts and sub-parts by introducing novel pairwise SVM grammars and finally to detect the vehicle by applying the trained grammars. Experiments in practical urban scenarios are carried out for complex traffic surveillance. It can be shown that our method adapts to partial occlusion and various challenging cases.


      PubDate: 2015-04-24T18:38:57Z
       
  • An integrated solution for lane level irregular driving detection on
           highways
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Rui Sun , Washington Yotto Ochieng , Shaojun Feng
      Global Navigation Satellite Systems (GNSS) has been widely used in the provision of Intelligent Transportation System (ITS) services. Current meter level system availability can fulfill the road level applications, such as route guide, fleet management and traffic control. However, meter level of system performance is not sufficient for the advanced safety applications. These lane level safety applications requires centimeter/decimeter positioning accuracy, with high integrity, continuity and availability include lane control, collision avoidance and intelligent speed assistance, etc. Detecting lane level irregular driving behavior is the basic requirement for these safety related ITS applications. The two major issues involved in the lane level irregular driving identification are accessing to high accuracy positioning and vehicle dynamic parameters and extraction of erratic driving behaviour from this and other related information. This paper proposes an integrated solution for the lane level irregular driving detection. Access to high accuracy positioning is enabled by GNSS and Inertial Navigation System (INS) integration using filtering with precise vehicle motion models and lane information. The detection of different types of irregular driving behaviour is based on the application of a Fuzzy Inference System (FIS). The evaluation of the designed integrated systems in the field test shows that 0.5m accuracy positioning source is required for lane level irregular driving detection algorithm and the designed system can detect irregular driving styles.


      PubDate: 2015-04-24T18:38:57Z
       
  • Electric vehicles in multi-vehicle households
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Michael A. Tamor , Miloš Milačić
      The suitability of an electric vehicle of a given range to serve in place of a given conventional vehicle is not limited by the daily travel over distances within that that range, but rather by the occasional inconvenience of finding alternative transport for longer trips. While the frequency of this inconvenience can be computed from usage data, the willingness of individual users to accept that replacement depends on details of available transportation alternatives and their willingness to use them. The latter can be difficult to assess. Fortunately, 65% of US households have access to the most convenient alternative possible: a second car. In this paper we describe an analysis of prospective EV acceptance and travel electrification in two-car households in the Puget Sound region. We find that EVs with 60miles of useful range could be acceptable (i.e. incur inconvenience no more than three days each year) to nearly 90% of two-car households and electrify nearly 55% of travel in those households (32% of all travel). This compares to 120miles range required to achieve the same fraction of electrified travel via one-for-one replacement of individual vehicles. Even though only one third of personal vehicles in the US may be replaced in this paradigm, the ‘EV as a second-car’ concept is attractive in that a significant fraction of travel can be electrified by vehicles with modest electric range and virtually no dependence on public charging infrastructure.


      PubDate: 2015-04-24T18:38:57Z
       
  • Analyzing passenger train arrival delays with support vector regression
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Nikola Marković , Sanjin Milinković , Konstantin S. Tikhonov , Paul Schonfeld
      We propose machine learning models that capture the relation between passenger train arrival delays and various characteristics of a railway system. Such models can be used at the tactical level to evaluate effects of various changes in a railway system on train delays. We present the first application of support vector regression in the analysis of train delays and compare its performance with the artificial neural networks which have been commonly used for such problems. Statistical comparison of the two models indicates that the support vector regression outperforms the artificial neural networks. Data for this analysis are collected from Serbian Railways and include expert opinions about the influence of infrastructure along different routes on train arrival delays.


      PubDate: 2015-04-24T18:38:57Z
       
  • Categorizing bicycling environments using GPS-based public bicycle speed
           data
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Shinhye Joo , Cheol Oh , Eunbi Jeong , Gunwoo Lee
      A promising alternative transportation mode to address growing transportation and environmental issues is bicycle transportation, which is human-powered and emission-free. To increase the use of bicycles, it is fundamental to provide bicycle-friendly environments. The scientific assessment of a bicyclist’s perception of roadway environment, safety and comfort is of great interest. This study developed a methodology for categorizing bicycling environments defined by the bicyclist’s perceived level of safety and comfort. Second-by-second bicycle speed data were collected using global positioning systems (GPS) on public bicycles. A set of features representing the level of bicycling environments was extracted from the GPS-based bicycle speed and acceleration data. These data were used as inputs for the proposed categorization algorithm. A support vector machine (SVM), which is a well-known heuristic classifier, was adopted in this study. A promising rate of 81.6% for correct classification demonstrated the technical feasibility of the proposed algorithm. In addition, a framework for bicycle traffic monitoring based on data and outcomes derived from this study was discussed, which is a novel feature for traffic surveillance and monitoring.


      PubDate: 2015-04-24T18:38:57Z
       
  • Marginal cost congestion pricing based on the network fundamental diagram
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): M.D. Simoni , A.J. Pel , R.A. Waraich , S.P. Hoogendoorn
      Congestion pricing schemes have been traditionally derived based on analytical representations of travel demand and traffic flows, such as in bottleneck models. A major limitation of these models, especially when applied to urban networks, is the inconsistency with traffic dynamics and related phenomena such as hysteresis and the capacity drop. In this study we propose a new method to derive time-varying tolling schemes using the concept of the Network Fundamental Diagram (NFD). The adopted method is based on marginal cost pricing, while it also enables to account realistically for the dynamics of large and heterogeneous traffic networks. We derive two alternative cordon tolls using network-aggregated traffic flow conditions: a step toll that neglects the spatial distribution of traffic by simply associating the marginal costs of any decrease in production within the NFD to the surplus of traffic; and a step toll that explicitly accounts for how network performance is also influenced by the spatial variance in a 3D-NFD. This pricing framework is implemented in the agent-based simulation model MATSim and applied to a case study of the city of Zurich. The tolling schemes are compared with a uniform toll, and they highlight how the inhomogeneous distribution of traffic may compromise the effectiveness of cordon tolls.


      PubDate: 2015-04-24T18:38:57Z
       
  • Real-time estimation of lane-based queue lengths at isolated signalized
           junctions
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Seunghyeon Lee , S.C. Wong , Y.C. Li
      In this study, we develop a real-time estimation approach for lane-based queue lengths. Our aim is to determine the numbers of queued vehicles in each lane, based on detector information at isolated signalized junctions. The challenges involved in this task are to identify whether there is a residual queue at the start time of each cycle and to determine the proportions of lane-to-lane traffic volumes in each lane. Discriminant models are developed based on time occupancy rates and impulse memories, as calculated by the detector and signal information from a set of upstream and downstream detectors. To determine the proportions of total traffic volume in each lane, the downstream arrivals for each cycle are estimated by using the Kalman filter, which is based on upstream arrivals and downstream discharges collected during the previous cycle. Both the computer simulations and the case study of real-world traffic show that the proposed method is robust and accurate for the estimation of lane-based queue lengths in real time under a wide range of traffic conditions. Calibrated discriminant models play a significant role in determining whether there are residual queued vehicles in each lane at the start time of each cycle. In addition, downstream arrivals estimated by the Kalman filter enhance the accuracy of the estimates by minimizing any error terms caused by lane-changing behavior.


      PubDate: 2015-04-24T18:38:57Z
       
  • Does it pay to reveal safety information? The effect of safety
           information on flight choice
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Aliza Fleischer , Anat Tchetchik , Tomer Toledo
      The case of flights safety lends itself as a natural case study for choice under of information asymmetry that involves dread risk and emotional factors. Specifically it allows one to experiment how the releasing of information will affect consumer choice. Previous studies, which followed the deregulation of commercial aviation, raised concerns about the corresponding potential for a marked deterioration in airline safety. Measures to prevent that decline were subsequently proposed. Specifically, it was argued that the public sector should establish and release flight safety indicators in addition to accidents’ statistics, which are currently available. It was argued that such safety indicators will also enable airlines to diversify their safety offerings. Underlying this argument are the assumptions that consumers’ flight safety preferences vary and that, provided with safety information, consumers will use it when making decisions. The present work, however, refutes the first assumption and sheds light on the second. It further investigates whether and how consumers react to and interpret safety information when choosing a flight, while accounting explicitly for a psychological trait. Employing an advanced experimental design and econometric approach, we find that: 1. When formal flight safety ratings are supplied, individuals abandoned their priors and rely on the information provided. 2. When it comes to “bad death” probabilities, people are not sensitive to the different shades of safety, and instead, they simply discern flights as either safe or unsafe. 3. Under a certain conditions disclosed information can alleviated fear and change the decision making of airline passengers.


      PubDate: 2015-04-24T18:38:57Z
       
  • Vehicular Ad-Hoc Networks sampling protocols for traffic monitoring and
           incident detection in Intelligent Transportation Systems
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Andrea Baiocchi , Francesca Cuomo , Mario De Felice , Gaetano Fusco
      Vehicular Ad-Hoc Networks (VANETs) are an emerging technology soon to be brought to everyday life. Many Intelligent Transport Systems (ITS) services that are nowadays performed with expensive infrastructure, like reliable traffic monitoring and car accident detection, can be enhanced and even entirely provided through this technology. In this paper, we propose and assess how to use VANETs for collecting vehicular traffic measurements. We provide two VANET sampling protocols, named SAME and TOME, and we design and implement an application for one of them, to perform real time incident detection. The proposed framework is validated through simulations of both vehicular micro-mobility and communications on the 68km highway that surrounds Rome, Italy. Vehicular traffic is generated based on a large real GPS traces set measured on the same highway, involving about ten thousand vehicles over many days. We show that the sampling monitoring protocol, SAME, collects data in few seconds with relative errors less than 10%, whereas the exhaustive protocol TOME allows almost fully accurate estimates within few tens of seconds. We also investigate the effect of a limited deployment of the VANET technology on board of vehicles. Both traffic monitoring and incident detection are shown to still be feasible with just 50% of equipped vehicles.


      PubDate: 2015-04-24T18:38:57Z
       
  • Empirical analysis of free-floating carsharing usage: The Munich and
           Berlin case
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Stefan Schmöller , Simone Weikl , Johannes Müller , Klaus Bogenberger
      Carsharing has become an important addition to existing mobility services over the last years. Today, several different systems are operating in many big cities. For an efficient and economic operation of any carsharing system, the identification of customer demand is essential. This demand is investigated within the presented research by analyzing booking data of a German free-floating carsharing system. The objectives of this paper are to describe carsharing usage and to identify factors that have an influence on the demand for carsharing. Therefore, the booking data are analyzed for temporal aspects, showing recurring patterns of varying lengths. The spatial distribution of bookings is investigated using a geographic information system and indicates a relationship between city structure and areas with high demand for carsharing. The temporal and spatial facets are then combined by applying a cluster analysis to identify groups of days with similar spatial booking patterns and show asymmetries in the spatiotemporal distribution of vehicle supply and demand. Influences on demand can be either short-term or long-term. The paper shows that changes in the weather conditions are a short-term influence as users of free-floating carsharing react to those. Furthermore, the application of a linear regression analysis reveals that socio-demographic data are suitable for making long-term demand predictions since booking numbers show quite a strong correlation with socio-demography, even in a simple model.


      PubDate: 2015-04-24T18:38:57Z
       
  • A continuous-flow-intersection-lite design and traffic control for
           oversaturated bottleneck intersections
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): Weili Sun , Xinkai Wu , Yunpeng Wang , Guizhen Yu
      Oversaturation has become a severe problem for urban intersections, especially the bottleneck intersections that cause queue spillover and network gridlock. Further improvement of oversaturated arterial traffic using traditional mitigation strategies, which aim to improve intersection capacity by merely adjusting signal control parameters, becomes challenging since exiting strategies may (or already) have reached their “theoretical” limits of optimum. Under such circumstance, several novel unconventional intersection designs, including the well-recognized continuous flow intersection (CFI) design, are originated to improve the capacity at bottleneck intersections. However, the requirement of installing extra sub-intersections in a CFI design would increase vehicular stops and, more critically, is unacceptable in tight urban areas with closed spaced intersections. To address these issues, this research proposes a simplified continuous flow intersection (called CFI-Lite) design that is ideal for arterials with short links. It benefits from the CFI concept to enable simultaneous move of left-turn and through traffic at bottleneck intersections, but does not need installation of sub-intersections. Instead, the upstream intersection is utilized to allocate left-turn traffic to the displaced left-turn lane. It is found that the CFI-Lite design performs superiorly to the conventional design and regular CFI design in terms of bottleneck capacity. Pareto capacity improvement for every traffic stream in an arterial system can be achieved under effortless conditions. Case study using data collected at Foothill Blvd in Los Angeles, CA, shows that the new design is beneficial in more than 90% of the 408 studied cycles. The testing also shows that the average improvements of green bandwidths for the synchronized phases are significant.


      PubDate: 2015-04-24T18:38:57Z
       
  • A heuristic model of bounded route choice in urban areas
    • Abstract: Publication date: July 2015
      Source:Transportation Research Part C: Emerging Technologies, Volume 56
      Author(s): E.J. Manley , S.W. Orr , T. Cheng
      There is substantial evidence to indicate that route choice in urban areas is complex cognitive process, conducted under uncertainty and formed on partial perspectives. Yet, conventional route choice models continue make simplistic assumptions around the nature of human cognitive ability, memory and preference. In this paper, a novel framework for route choice in urban areas is introduced, aiming to more accurately reflect the uncertain, bounded nature of route choice decision making. Two main advances are introduced. The first involves the definition of a hierarchical model of space representing the relationship between urban features and human cognition, combining findings from both the extensive previous literature on spatial cognition and a large route choice dataset. The second advance involves the development of heuristic rules for route choice decisions, building upon the hierarchical model of urban space. The heuristics describe the process by which quick, ‘good enough’ decisions are made when individuals are faced with uncertainty. This element of the model is once more constructed and parameterised according to findings from prior research and the trends identified within a large routing dataset. The paper outlines the implementation of the framework within a real-world context, validating the results against observed behaviours. Conclusions are offered as to the extension and improvement of this approach, outlining its potential as an alternative to other route choice modelling frameworks.


      PubDate: 2015-04-19T12:07:04Z
       
 
 
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