An exact modelling of the uniform control traffic delay in undersaturated signalized intersections

The average delay experienced by vehicles at a signalized intersection defines the level of service (LOS) at which the intersection operates. A major challenge in this regard is the ability to accurately estimate all the components underlying the overall control delay, including the uniform, incremental and initial queue delays. This paper tackles this challenging task by proposing a novel exact model of the uniform control delay component with a view to enhancing the accuracy of the existing approximate models, notably, the one reported in the Highway Capacity Manual 2010. Both graphical and analytical proofs are employed to derive exact closed‐form expressions for the uniform control delay at undersaturated signalized intersections. The high degree of accuracy of the proposed models is analysed through extensive simulations to demonstrate their abilities to exactly characterize the performance of real‐life intersections in terms of the resulting vehicle delay. Unlike the existing widely adopted uniform delay models, which tend to overestimate the LOS of real‐life intersections, the delay models introduced in this paper have the merit of exactly capturing such a LOS. Copyright © 2016 John Wiley & Sons, Ltd.     

Understanding connectivity to international markets: a systematic review

Improving freight connectivity is increasingly a topic at the centre of the international trade and transport policy agendas. An examination of available documents and studies in both the policy-making and the academic fields shows that the concept of freight connectivity has often been defined in different ways, and thus has taken a variety of meanings. This poses the question on what connectivity is and what are its determinants in the context of international trade. We are not aware of any studies that have analysed, in a systematic way, the different perspectives and determinants of freight connectivity so as to increase access to international markets. This paper seeks to fill this gap by performing a systematic literature review that spans disciplines such as Transport Engineering, Transport and International Economics, and Supply Chain Management. The outcome of this examination is a multidisciplinary framework that hopefully will help stakeholders to understand freight connectivity to international markets better, as well as guide future research and analysis in policy-making.     

A new efficient EDI system for container cargo logistics

There have been many efforts to develop a logistics information system in the Korean logistics industry. In spite of these efforts, there are many points which need improvement in the Logistics Information System, of which function is the electronic data communication without added value. This paper aims to describe some of the main problems and the successful factors which are being found in the evolution of the present EDI systems for clearing import/export container cargoes, with special reference to Singapore, Korea, and Japan. Following this, leaving legal issues aside, to suggest workable guidelines for designing a new efficient EDI system for container cargo logistics. As a result of the review, the following successful factors are drawn: (a) the planning, requirement analysis and design of EDI are critical, as it provides a framework for its implementation; (b) as the data of customs clearance are an integral part of a logistics EDI system, the inclusion of customs in the system design is essential; (c) the sharing system of cargo data as the framework of the logistics EDI is efficient for data interchange; (d) the EDI software for the user has been developed and provided by an EDI network operating company; and (e) to facilitate communication between trading partners and the transport sector, it is necessary to adopt a global message standard, such as EDIFACT.     

Extending stated choice analysis to recognise agent-specific attribute endogeneity in bilateral group negotiation and choice: a think piece

This paper is a think piece on variations in the structure of stated preference studies when modelling the joint preferences of interacting agents who have the power to influence the attribute levels on offer. The approach proposed is an extension of standard stated choice methods, known as ‘stated endogenous attribute level’ (SEAL) analysis. It allows for interactive agents to adjust attribute levels off a base stated choice specification that are within their control, in an effort to reach agreement in an experimental setting. This accomplishes three goals: (1) the ability to place respondents in an environment that more closely matches interactive settings in which some attribute levels are endogenous to a specific agent, should the modeller wish to capture such behaviour; (2) the improved ability of the modeller to capture the behaviour in such settings, including a greater wealth of information on the related interaction processes, rather than simply outcomes; and (3) the expansion of the set of situations that the modeller can investigate using experimental data.

Safety Evaluation for Freeway Exit Ramp Based on Speed Consistency

Speed differential has direct relationship with road safety. Conventional speed consistency measures draw sample data from independent population that follows a normal distribution. These methods may fall into ecological fallacy and overestimate the safety level of road elements. After deducing the relationship between the difference in operating speed ΔV₈₅ and85(ΔV), the 85^th percentile value of individual speed reduction, this paper recommends 85(ΔV) and speed reduction rate 85(ΔV)R is used to evaluate ramp safety. Point speeds of individual vehicle at freeway diverge area, upper ramp, and lower ramp are collected by radar guns. Safety performance of 37 exit ramps are appraised using three different measures, namely, ΔV₈₅, 85(ΔV), and 85(ΔV)R. The results show that 85(ΔV) is 1.42 to 2.02 times of ΔV₈₅, and that the evaluation result of 85(ΔV)R is between the other two. The measure 85(ΔV)R considers not only individual speed but also the base speed on upstream element, which avoid the pitfalls of ecological fallacy and overestimation possessed by conventional measures. It is a safer and reasonable measure that should be adopted in practice.     

Workshop 3B: Governance,ownership and competition issues in deregulated (free market) public transport: Lessons that can be learnt from developed and developing economies

The past emphasis in this conference series has been on the best ways to deregulate regulated public transport markets. This workshop reverses this process by examining the best ways to regulate deregulated public transport markets. A hierarchy of regulatory needs is identified and three hybrid models examined, based loosely on experience from Great Britain, New Zealand and Sweden. It is argued that deregulated public transport markets are a global phenomenon but regulatory measures should reflect local requirements. The resultant process of glocalisation might result in regulatory measures that focus on the rules of law and their enforcement in emerging public transport markets (such as urban transport in Sub Saharan Africa and for the soon to be competitive inter urban market in Germany) but that focus on guidance for network integration and incentivisation for welfare maximisation in more mature public transport markets (as in Great Britain, New Zealand and Sweden).     

Sample size requirements for stated choice experiments

Stated choice (SC) experiments represent the dominant data paradigm in the study of behavioral responses of individuals, households as well as other organizations, yet in the past little has been known about the sample size requirements for models estimated from such data. Traditional orthogonal designs and existing sampling theories does not adequately address the issue and hence researchers have had to resort to simple rules of thumb or ignore the issue and collect samples of arbitrary size, hoping that the sample is sufficiently large enough to produce reliable parameter estimates, or are forced to make assumptions about the data that are unlikely to hold in practice. In this paper, we demonstrate how a recently proposed sample size computation can be used to generate so-called S-efficient designs using prior parameter values to estimate panel mixed multinomial logit models. Sample size requirements for such designs in SC studies are investigated. In a numerical case study is shown that a D-efficient and even more an S-efficient design require a (much) smaller sample size than a random orthogonal design in order to estimate all parameters at the level of statistical significance. Furthermore, it is shown that wide level range has a significant positive influence on the efficiency of the design and therefore on the reliability of the parameter estimates.     

Choosing Public Transport—Incorporating Richer Behavioural Elements in Modal Choice Models

The development of behaviourally richer representations of the role of well-established and increasingly important influences on modal choice, such as trip time reliability and accounting for risk attitude and process rules, has moved forward at a fast pace in the context of automobile travel. In the public transport setting, such contributions have, with rare exception, not been considered. In this paper, we discuss and empirically illustrate the merits of advanced modelling developments aimed at improving our understanding of public transport choice, namely the inclusion of reliability in extended expected utility theoretic forms, to recognize risk attitude and perceptual conditioning, the consideration of passenger crowding and its inclusion in linear additive models, and the role of multiple heuristics in representing attribute processing as a way of conditioning modal choice. We illustrate the mechanics of introducing these behaviourally appealing extensions using a modal choice data set collected in Sydney.     

A computationally efficient two-stage method for short-term traffic prediction on urban roads

Abstract

Short-term traffic prediction plays an important role in intelligent transport systems. This paper presents a novel two-stage prediction structure using the technique of Singular Spectrum Analysis (SSA) as a data smoothing stage to improve the prediction accuracy. Moreover, a novel prediction method named Grey System Model (GM) is introduced to reduce the dependency on method training and parameter optimisation. To demonstrate the effects of these improvements, this paper compares the prediction accuracies of SSA and non-SSA model structures using both a GM and a more conventional Seasonal Auto-Regressive Integrated Moving Average (SARIMA) prediction model. These methods were calibrated and evaluated using traffic flow data from a corridor in Central London under both normal and incident traffic conditions. The prediction accuracy comparisons show that the SSA method as a data smoothing step before the application of machine learning or statistical prediction methods can improve the final traffic prediction accuracy. In addition, the results indicate that the relatively novel GM method outperforms SARIMA under both normal and incident traffic conditions on urban roads.