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  • JOURNAL ARTICLE
    Trompet M, Anderson RJ, Graham DJ, 2018,

    Improved understanding of the relative quality of bus public transit using a balanced approach to performance data normalization☆

    , Transportation Research Part A: Policy and Practice, Vol: 114, Pages: 13-23, ISSN: 0965-8564

    © 2017 Elsevier Ltd In order for bus operators and/or their respective authorities to understand where service quality can improve, it is useful to systematically compare performance with organizations displaying similarities in types of services offered, operational characteristics and density of the service area. These similar characteristics enable peer organizations to benchmark performance once their operational data are normalized for differences in scale of operations. The most commonly used normalization factors for the demand side output are passenger boardings and passenger kilometres. For the supply side output these are vehicle kilometres and vehicle hours. Through twelve years of experience in the International Bus Benchmarking Group (IBBG) a better understanding of differences in service characteristics between ‘similar’ peers has been achieved, which highlight a challenge for the interpretation of normalized performance. It became clear that relative performance should often not be concluded from performance indicators normalized in a single dimension. Variety between peers in commercial speed, trip length, vehicle planning capacity, vehicle weight and network efficiency result in the need for a bi-dimensional or balanced approach to data normalization. This paper quantifies the variety within these operational characteristics and provides examples of the interpretation bias this may lead to. A framework is provided for use by bus organization management, policymakers and benchmarking practitioners that suggests applicable combinations of denominators for a balanced normalization process, leading to improved understanding of relative performance.

  • JOURNAL ARTICLE
    Barron A, Canavan S, Anderson R, Cohen Jet al., 2018,

    Operational Impacts of Platform Doors in Metros

    , Transportation Research Record, ISSN: 0361-1981

    © 2018, National Academy of Sciences: Transportation Research Board 2018. Platform doors are increasingly installed by metros, primarily to improve safety. However, they have the potential for both positive and negative operational impacts, mostly by affecting dwell times at stations. Using data from the CoMET and Nova international metro benchmarking consortia of 33 metro systems, this paper seeks to understand and quantify these operational impacts. Overall, platform doors have a net negative impact on dwell times, leading to between 4 and 15 s of extra time per station stop. This is due to the additional time required for the larger doors to open and close, slower passenger movements due to the additional distance between platforms and trains, and, most importantly, extended departure delays after both sets of doors are closed caused by the need to ensure safety (that no one is trapped in the gap between the two sets of doors). This is a particular problem in mainland China, where metros conduct manual safety checks that require drivers to step out of trains onto platforms. However, despite longer dwell times, platform doors have a net positive impact on metro operations, largely due to the many safety benefits that also reduce delays and thereby improve service performance. There are also potential benefits regarding energy and ventilation. To mitigate the negative impacts, metros should seek to refine procedures and improve technology to reduce dwell time delays caused by platform doors. Reducing or eliminating these extra delays are essential to delivering efficient service and maximum capacity, provided that safety can be assured.

  • JOURNAL ARTICLE
    Barzin S, D'Costa S, Graham DJ, 2018,

    A pseudo - panel approach to estimating dynamic effects of road infrastructure on firm performance in a developing country context

    , REGIONAL SCIENCE AND URBAN ECONOMICS, Vol: 70, Pages: 20-34, ISSN: 0166-0462
  • JOURNAL ARTICLE
    Melo PC, Graham DJ, 2018,

    Transport-induced agglomeration effects: Evidence for US metropolitan areas

    , REGIONAL SCIENCE POLICY AND PRACTICE, Vol: 10, Pages: 37-47, ISSN: 1757-7802
  • JOURNAL ARTICLE
    Hoercher D, Graham DJ, 2018,

    Demand imbalances and multi-period public transport supply

    , TRANSPORTATION RESEARCH PART B-METHODOLOGICAL, Vol: 108, Pages: 106-126, ISSN: 0191-2615
  • JOURNAL ARTICLE
    Horcher D, Graham DJ, Anderson RJ, 2018,

    The Economic Inefficiency of Travel Passes Under Crowding Externalities and Endogenous Capacity

    , JOURNAL OF TRANSPORT ECONOMICS AND POLICY, Vol: 52, Pages: 1-22, ISSN: 0022-5258
  • JOURNAL ARTICLE
    Canavan S, Graham DJ, Anderson RJ, Barron Aet al., 2018,

    Urban Metro Rail Demand: Evidence from Dynamic Generalized Method of Moments Estimates using Panel Data

    , Transportation Research Record, ISSN: 0361-1981

    © National Academy of Sciences: Transportation Research Board 2018. This paper estimates elasticities of demand for metro services with respect to fares, income, quality of service, population and network length. Data for 32 world metro systems covering the period from 1996 to 2015 are analyzed within a dynamic panel data specification. Three key contributions are made. First, we collate a database for estimation that is more extensive than that used in previous studies. Second, the quality of the data we have available allows us to more accurately represent quality of service than has been possible previously. Lastly, we estimate and compare two different measures of demand. Our analysis finds a statistically significant negative fare elasticity of −0.25 in the long run for a passenger km specified model and −0.4 in the long run for a passenger journey specified model, and a positive long run income elasticity of 0.17 and 0.18 for the passenger km and passenger journey models respectively. Regarding quality of service, we find positive long run elasticities of 0.56 and 0.47 for the passenger km and passenger journey models respectively. Income levels, population, and the size of the network are also found to be statistically significant and positive in nature. The results suggest passenger km and passenger journeys will increase more in response to changes in service (here represented by increased capacity) than to changes in fares, with the difference in elasticities of service and fares being more pronounced for passenger km.

  • JOURNAL ARTICLE
    Horcher D, Graham DJ, Anderson RJ, 2018,

    The economics of seat provision in public transport

    , TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW, Vol: 109, Pages: 277-292, ISSN: 1366-5545
  • JOURNAL ARTICLE
    Sun R, Cheng Q, Xue D, Wang G, Ochieng WYet al., 2017,

    GNSS/Electronic Compass/Road Segment Information Fusion for Vehicle-to-Vehicle Collision Avoidance Application.

    , Sensors (Basel), Vol: 17

    The increasing number of vehicles in modern cities brings the problem of increasing crashes. One of the applications or services of Intelligent Transportation Systems (ITS) conceived to improve safety and reduce congestion is collision avoidance. This safety critical application requires sub-meter level vehicle state estimation accuracy with very high integrity, continuity and availability, to detect an impending collision and issue a warning or intervene in the case that the warning is not heeded. Because of the challenging city environment, to date there is no approved method capable of delivering this high level of performance in vehicle state estimation. In particular, the current Global Navigation Satellite System (GNSS) based collision avoidance systems have the major limitation that the real-time accuracy of dynamic state estimation deteriorates during abrupt acceleration and deceleration situations, compromising the integrity of collision avoidance. Therefore, to provide the Required Navigation Performance (RNP) for collision avoidance, this paper proposes a novel Particle Filter (PF) based model for the integration or fusion of real-time kinematic (RTK) GNSS position solutions with electronic compass and road segment data used in conjunction with an Autoregressive (AR) motion model. The real-time vehicle state estimates are used together with distance based collision avoidance algorithms to predict potential collisions. The algorithms are tested by simulation and in the field representing a low density urban environment. The results show that the proposed algorithm meets the horizontal positioning accuracy requirement for collision avoidance and is superior to positioning accuracy of GNSS only, traditional Constant Velocity (CV) and Constant Acceleration (CA) based motion models, with a significant improvement in the prediction accuracy of potential collision.

  • JOURNAL ARTICLE
    Ali BS, Ochieng WY, Zainudin R, 2017,

    An analysis and model for Automatic Dependent Surveillance Broadcast (ADS-B) continuity

    , GPS SOLUTIONS, Vol: 21, Pages: 1841-1854, ISSN: 1080-5370
  • JOURNAL ARTICLE
    Sun R, Cheng Q, Wang G, Ochieng WYet al., 2017,

    A Novel Online Data-Driven Algorithm for Detecting UAV Navigation Sensor Faults.

    , Sensors (Basel), Vol: 17

    The use of Unmanned Aerial Vehicles (UAVs) has increased significantly in recent years. On-board integrated navigation sensors are a key component of UAVs' flight control systems and are essential for flight safety. In order to ensure flight safety, timely and effective navigation sensor fault detection capability is required. In this paper, a novel data-driven Adaptive Neuron Fuzzy Inference System (ANFIS)-based approach is presented for the detection of on-board navigation sensor faults in UAVs. Contrary to the classic UAV sensor fault detection algorithms, based on predefined or modelled faults, the proposed algorithm combines an online data training mechanism with the ANFIS-based decision system. The main advantages of this algorithm are that it allows real-time model-free residual analysis from Kalman Filter (KF) estimates and the ANFIS to build a reliable fault detection system. In addition, it allows fast and accurate detection of faults, which makes it suitable for real-time applications. Experimental results have demonstrated the effectiveness of the proposed fault detection method in terms of accuracy and misdetection rate.

  • JOURNAL ARTICLE
    Qin F, Sun R, Ochieng WY, Feng S, Han K, Wang Yet al., 2017,

    Integrated GNSS/DR/road segment information system for variable road user charging

    , TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES, Vol: 82, Pages: 261-272, ISSN: 0968-090X
  • CONFERENCE PAPER
    Achurra Gonzalez PE, Angeloudis P, Hu S, Zavitsas K, Graham DJet al.,

    Modelling the impact of infrastructure developments on the resilience of intermodal container transport networks: One-Belt-One-Road Case study

    , 7th International Conference on Logistics and Maritime Systems
  • JOURNAL ARTICLE
    Bu J, Sun R, Bai H, Xu R, Xie F, Zhang Y, Ochieng WYet al., 2017,

    Integrated method for the UAV navigation sensor anomaly detection

    , IET Radar, Sonar and Navigation, Vol: 11, Pages: 847-853, ISSN: 1751-8784

    © 2016, The Institution of Engineering and Technology. The rapid development of unmanned aerial vehicles (UAVs) has made great progress for its widespread uses in military and civilian applications in recent years. On-board integrated navigation sensors are essential for UAV flight control systems in that they must operate with robustness and reliability. To achieve this, timely and effectively anomaly detection capabilities for the estimated UAV status from the integrated navigation sensors are required to ensure the UAV flight safety. Extraction of the anomaly information from the real-time navigation sensors and designing a robust and reliable anomaly detection algorithm are major issues for the UAV navigation sensor anomaly detection. This study introduces a novel integrated algorithm for detecting UAV on-board navigation sensor anomaly, by combining particle filter (PF) estimated state residuals with fuzzy inference system (FIS) decision system. The residual information is obtained based on the difference between the collected Global Positioning System measurements and high accuracy PF estimates. The indicators derived from the PF residuals are further made as inputs for the FIS system to output the different anomaly levels. The simulation and filed test results have demonstrated the effectiveness and efficiency of the proposed anomaly detection method in terms of timeliness, recall and precision.

  • REPORT
    Mundy D, Trompet M, Cohen J, Graham Det al., 2017,

    The Identification and Management of Bus Priority Schemes; A Study of International Experiences and Best Practices

    Priority measures for bus services can deliver significant benefits both for passengers and the operator. For example, green light priority or the conversion of road space to dedicated bus lanes can deliver journey time (variability/predictability) benefits thereby improving both quality of service and operational efficiency. This study investigates how bus priority schemes are identified, selected and managed in 14 different cities across Asia, Australia, Europe and North America. The study reviews the decision making processes, including associated input from bus operators, involved in identifying necessary bus schemes. The study provides examples of succesful and unsuccessful bus priority schemes and methods of bus priority enforcement are explored to establish interesting and successful ways to ensure bus priority measures can be effective. This report may be useful to different stakeholders experiencing difficulties with bus priority selection, implementation and management, such as city/ borough governments, road authorities, bus operators, passenger groups, police, and other organisations.

  • JOURNAL ARTICLE
    Zhang X, Zhan X, Feng S, Ochieng Wet al., 2017,

    An Analytical Model for BDS B1 Spreading Code Self-Interference Evaluation Considering NH Code Effects

    , SENSORS, Vol: 17, ISSN: 1424-8220
  • JOURNAL ARTICLE
    Li H, Graham DJ, Liu P, 2017,

    Safety effects of the London cycle superhighways on cycle collisions

    , ACCIDENT ANALYSIS AND PREVENTION, Vol: 99, Pages: 90-101, ISSN: 0001-4575
  • JOURNAL ARTICLE
    Sidiropoulos S, Han K, Majumdar A, Ochieng WYet al., 2017,

    Robust identification of air traffic flow patterns in Metroplex terminal areas under demand uncertainty

    , TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES, Vol: 75, Pages: 212-227, ISSN: 0968-090X
  • CONFERENCE PAPER
    Achurra Gonzalez PE, Angeloudis P, Zavitsas K, Niknejad SA, Graham DJet al.,

    A Quantitative Framework for Assessment of Network Vulnerability in Liner Shipping Networks

    , Transportation Research Board 96th Annual Meeting
  • JOURNAL ARTICLE
    Ali BS, Schuster W, Ochieng WY, 2017,

    Evaluation of the Capability of Automatic Dependent Surveillance Broadcast to Meet the Requirements of Future Airborne Surveillance Applications

    , Journal of Navigation, Vol: 70, Pages: 49-66, ISSN: 0373-4633

    © 2016 The Royal Institute of Navigation. Automatic Dependent Surveillance Broadcast (ADS-B) Out supports various ground applications including Air Traffic Control (ATC) surveillance in radar airspace, non-radar airspace and on the airport surface. In addition, the capability of aircraft to receive ADS-B Out messages from other aircraft within their coverage (ADS-B In) enables enhanced airborne surveillance applications. The requirements of the application vary depending on its safety-criticality. More stringent applications will require higher levels of performance. It is therefore critical that the ADS-B system performance is measured against the most stringent application it is designed for. This paper reviews the various enhanced airborne surveillance applications and the required ADS-B information to support them. It identifies the ADS-B based applications required for Air Traffic Management (ATM) modernisation under the SESAR/NextGen programs. It discusses existing ADS-B Out versions and their capabilities. A mapping exercise is undertaken to assess the credibility of the ADS-B system performance to support the functionalities and requirements of the various enhanced airborne surveillance applications and establish those that require further research and development, highlighting some of the key challenges.

  • JOURNAL ARTICLE
    Shang W, Han K, Ochieng W, Angeloudis Pet al., 2017,

    Agent-based day-to-day traffic network model with information percolation

    , TRANSPORTMETRICA A-TRANSPORT SCIENCE, Vol: 13, Pages: 38-66, ISSN: 2324-9935
  • JOURNAL ARTICLE
    Melo PC, Graham DJ, Levinson D, Aarabi Set al., 2017,

    Agglomeration, accessibility and productivity: Evidence for large metropolitan areas in the US

    , URBAN STUDIES, Vol: 54, Pages: 179-195, ISSN: 0042-0980
  • JOURNAL ARTICLE
    Mohammad SI, Graham DJ, Melo PC, 2017,

    The effect of the Dubai Metro on the value of residential and commercial properties

    , JOURNAL OF TRANSPORT AND LAND USE, Vol: 10, Pages: 263-290, ISSN: 1938-7849
  • JOURNAL ARTICLE
    Piner D, Condry B, 2017,

    International best practices in managing unplanned disruption to suburban rail services

    , WORLD CONFERENCE ON TRANSPORT RESEARCH - WCTR 2016, Vol: 25, ISSN: 2352-1465
  • JOURNAL ARTICLE
    Morse L, Trompet M, Barron A, Graham DJet al., 2017,

    Development of a Key Performance Indicator System to Benchmark Relative Paratransit Performance

    , TRANSPORTATION RESEARCH RECORD, Pages: 1-8, ISSN: 0361-1981
  • JOURNAL ARTICLE
    Sun R, Xie F, Xue D, Zhang Y, Ochieng WYet al., 2017,

    A Novel Rear-End Collision Detection Algorithm Based on GNSS Fusion and ANFIS

    , Journal of Advanced Transportation, Vol: 2017, ISSN: 0197-6729

    © 2017 Rui Sun et al. Rear-end collisions are one of the most common types of accidents on roads. Global Satellite Navigation Systems (GNSS) have recently become sufficiently flexible and cost-effective in order to have great potential for use in rear-end collision avoidance systems (CAS). Nevertheless, there are two main issues associated with current vehicle rear-end CAS: (1) achieving relative vehicle positioning and dynamic parameters with sufficiently high accuracy and (2) a reliable method to extract the car-following status from such information. This paper introduces a novel integrated algorithm for rear-end collision detection. Access to high accuracy positioning is enabled by GNSS, electronic compass, and lane information fusion with Cubature Kalman Filter (CKF). The judgment of the car-following status is based on the application of the Adaptive Neurofuzzy Inference System (ANFIS). The field test results show that the designed algorithm could effectively detect rear-end collisions with an accuracy of 99.61% and a false alarm rate of 5.26% in the 10 Hz output rate.

  • JOURNAL ARTICLE
    Hoercher D, Graham DJ, Anderson RJ, 2017,

    Crowding cost estimation with large scale smart card and vehicle location data

    , TRANSPORTATION RESEARCH PART B-METHODOLOGICAL, Vol: 95, Pages: 105-125, ISSN: 0191-2615
  • JOURNAL ARTICLE
    Li H, Graham DJ, 2016,

    Heterogeneous treatment effects of speed cameras on road safety

    , ACCIDENT ANALYSIS AND PREVENTION, Vol: 97, Pages: 153-161, ISSN: 0001-4575
  • JOURNAL ARTICLE
    Brage-Ardao R, Graham DJ, Anderson RJ, 2016,

    Determinants of rolling stock maintenance cost in metros

    , PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT, Vol: 230, Pages: 1487-1495, ISSN: 0954-4097
  • JOURNAL ARTICLE
    Sun R, Han K, Hu J, Wang Y, Hu M, Ochieng WYet al., 2016,

    Integrated solution for anomalous driving detection based on BeiDou/GPS/IMU measurements

    , TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES, Vol: 69, Pages: 193-207, ISSN: 0968-090X

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