A continuum model for the dispersion of traffic on two-lane roads

A continuum model for two-lane traffic flow is developed using the theory of kinematic waves in which the wavespeeds in the two lanes are assumed constant but unequal. The transient behaviour is found exactly using Riemann's method of characteristics and an asymptotic model of the long time flow is described. It is shown, that for large times, the traffic concentration moves with a weighted mean wavespeed of the two lanes and disperses about this mean speed as a result of interlane concentration differences generated by the relative wavespeeds. The dispersion can be described by a virtual coefficient of diffusion proportional to the square of the differences of the two wavespeeds and inversely proportional to the rate of lane changing. The technique is extended to describe three-lane traffic flow and to include the dependence of wavespeed upon concentration.     

A Cooperative Intelligent Transport Systems (C‐ITS)‐based lane‐changing advisory for weaving sections

Weaving sections, a common design of motorways, require extensive lane‐change manoeuvres. Numerous studies have found that drivers tend to make their lane changes as soon as they enter the weaving section, as the traffic volume increases. Congestion builds up as a result of this high lane‐changing concentration. Importantly, such congestion also limits the use of existing infrastructure, the weaving section downstream. This behaviour thus affects both safety and operational aspects. The potential tool for managing motorways effectively and efficiently is cooperative intelligent transport systems (C‐ITS). This research investigates a lane‐change distribution advisory application based on C‐ITS for weaving vehicles in weaving sections. The objective of this research is to alleviate the lane‐changing concentration problem by coordinating weaving vehicles to ensure that such lane‐changing activities are evenly distributed over the existing weaving length. This is achieved by sending individual messages to drivers based on their location to advise them when to start their lane change. The research applied a microscopic simulation in aimsun to evaluate the proposed strategy's effectiveness in a one‐sided ramp weave. The proposed strategy was evaluated using different weaving advisory proportions, traffic demands and penetration rates. The evaluation revealed that the proposed lane‐changing advisory has the potential to significantly improve delay. Copyright © 2016 John Wiley & Sons, Ltd.     

Transfer demand prediction for timed transfer coordination in public transport operational control

Timed transfer coordination in public transit reduces passenger transfer time by providing seamless interconnected transfers. The problem arises when a Receiving Vehicle (RV) arrives to the transfer stop before a Feeding Vehicle (FV) carrying transferring passengers. Timed transfer coordination in operational control dynamically decides whether a RV is held at the transfer stop to allow transfers, or departs as scheduled. While transfer demand is essential for implementing timed transfer coordination, this variable is generally not available in public transit because of the lack of passenger transfer plans. The problem of acquiring this variable in real‐time has also received limited attention in the related literature. This paper proposes a new method to dynamically predict the transfer demand. We anticipate the transferring probability from each individual passenger by examining historical travel itineraries. Three different types of models (simple analytical, statistical, and computation intelligence model) are developed to forecast the number of transferring passengers. Numerical experiments using observed Automatic Vehicle Location and Automatic Fare Collection data from South East Queensland, Australia show the accuracy and applicability of the proposed models in timed transfer coordination. Copyright © 2017 John Wiley & Sons, Ltd.     

Queue discharge patterns at signalized intersections with green signal countdown device and long cycle length

Two apparent features that prevail at signalized intersections in China are green signal countdown device and long cycle lengths. The objective of this study is to investigate the impacts of green signal countdown device and long cycle length on queue discharge patterns and to discuss its implications on capacity estimation in the context of China's traffic. At five typical large intersections in Shanghai and Tianjin, 11 through lanes were observed, and 9251 saturation headways were obtained as valid samples. Statistical analyses indicate that the discharge process of queuing vehicles can be divided into three distinct stages according to the discharge flow rate: a start‐up stage, a steady stage, and a rush stage. The average time for queuing vehicles to reach a stationary saturation flow rate, that is, the start‐up stage, was found to be approximately 20–30 seconds; the rush stage usually occurs during the phase transition period. The finding is contrary to the conventional assumption that the discharge rate reaches a maximum value after the fourth vehicle is discharged and then remains constant during the green time until the queue is completely dissolved. The capacity estimation errors that might arise from the conventional methods are discussed through a comparative study and a sensitivity analysis that are based on the identified queue discharge patterns. In addition, a piecewise linear regression method was proposed in order to reduce such errors. The proposed method can be used for capacity estimation at signalized intersections with the identified queue discharge patterns. Copyright © 2017 John Wiley & Sons, Ltd.     

Spreading distinctive insignia benefits from mobile service: evidence from a mobile application of transportation

ABSTRACT

Mobile commerce (m-commerce) faces a growing array of client devices for which applications are designed. Applications developed for general consumer use must be compatible with a wide range of devices. This research investigates how perceived usefulness and enjoyment affect intention to use a mobile application service (T-Express). In this study, we formulate a commitment model from the perspective of the social identity and technology acceptance perspective. Empirical data were collected by conducting a field survey of users of T-Express from Taiwan High Speed Rail Corporation (THSRC) stations in Taiwan. The main findings of the study are that wireless technology provides great value to businesses when it allows consumers to access real-time data to make timely decisions that either decrease costs or increase revenues; and to achieve a higher intention to use mobile applications, there should be a clear communication process between mobile application and passenger. Our findings indicate that one of the more overt illustrations of the power of packaging symbolism involves package design strategies that serve to provide a radical new upscale positioning for the THSRC brand.     

Safe design of personal rapid transit systems

The safety of personal rapid transit systems involves careful attention to all features of the design such as the use of a hierarchy of fault-tolerant redundant control systems, bi-stable fail-safe switching, back-up power supplies, vehicle and passenger protection, and attention to the interaction of people with the system. Safety, together with reliability and adequate capacity, must be achieved while making the system economically attractive, hence techniques to achieve these goals at minimum life-cycle cost are primary in PRT design. Building on theory of safe, reliable, environmentally acceptable, and cost-effective design of PRT systems developed during the 1970′s, in 1981 the author and his colleagues initiated design of a new PRT system, now called Taxi 2000. The paper describes the relevant features of Taxi 2000 and principles of safe design incorporated into it.     

What transportation modeling needs from a GIS: a conceptual framework

Both the geographic information system (GIS) and transportation modeling environments have seen continually developing analytic concepts and techniques. However, these developments have seldom resulted in the integration of GISs and transportation models. This paper explores the potential inherent in merging of these environments through a systematic investigation of the fundamental basis of integration. To do this, the traditional four step transportation modeling process is extended to include input and output steps. We then define functional components for GIS data handling — data management, manipulation, and analysis. The steps of modeling are matched against the list of GIS data handling functions within a matrix‐based framework. GIS functions that enhance a land‐use based urban transportation modeling process are then categorized. Conclusions are drawn and directions for future developments are discussed.     

Longitudinal control of a vehicle

Generally applicable formulae for the gain constants in a proportional plus integral controller required for stable control of the speed of any vehicle in terms of natural frequency, damping ratio, vehicle mass, and thruster time constant are derived. An example, based on a simulation of the controller and vehicle, is given. The theory shows that only speed and position feedback are needed. Acceleration feedback is unnecessary.     

The shape of MaaS: The potential for MaaS Lite

Mobility as a Service (MaaS) is about improving mobility for people. Since Gothenburg piloted the first multi-modal Mobility as a Service (MaaS) scheme from 2012, there have been many further attempts at introducing connected and bundled services globally, invariably provided as a mobile app and a single, simple ticketing interface. As in any emerging paradigm, the varying flavour, or ‘shapes’ of MaaS that are piloted reflect the search for a sustainable business model and connectivity between transport operators at varying levels that includes risk reallocation and data sharing. The varying levels of success of MaaS and Mobility on Demand (MOD) lead the authors to propose MaaS Lite, which reflects an incremental approach to MaaS based on a simpler organisational arrangement that does not depend upon the introduction of a Mobility Operator as a new player. MaaS Lite also recognises that most trips are not complex at all, often based on one or two connected mechanised modes that meets highly local needs, including FMLM service connectivity.Overall, MaaS is not a ‘one size fits all’ solution for all regions but the benefits of the highly targeted MaaS Lite could realise early public benefits as a first step in the development of a multi-phased ‘services road map’ that evolves towards the implementation of multi-modal, region-wide operationally integrated MaaS. Case studies in Hong Kong and Brisbane demonstrate the merits of MaaS Lite in these two contrasting environments having different regulatory regimes, population densities and levels of private car ownership.