Combining driver response with cyclical queue optimisation over selected corridors

A case study located in Auckland, New Zealand, was used to quantify the magnitude of savings that may result if the SCATS adaptive traffic control system contains an explicitly combined queue estimation and offset adjustment on a cycle‐by‐cycle basis. A validated SATURN traffic model was used to evaluate five scenarios that represent the short‐run and long‐run efficiency gains resulting from progressive signal adaption with an objective of queue minimisation on the main corridors. Optimisation was applied both area‐wide, and on selected arterial corridors, using a combined split/offset optimisation routine with responsive driver behaviour to achieve a network‐wide and corridor‐specific efficiency gain. The modelling heuristic evaluates the efficiency of both the Equisat and P₀ optimisation policies that would mimic a more progressive adaption of signals under SCATS. Results for the long‐run area‐wide optimisation can produce network‐wide travel‐time savings in the order of 20% and a reduction in transient queues of 28% if only selected corridors are optimised, with a 5% reduction in journey time over an average 8‐min journey. Copyright © 2016 John Wiley & Sons, Ltd.     

Real-time traffic estimation using data expansion

This paper presents a method for estimating missing real-time traffic volumes on a road network using both historical and real-time traffic data. The method was developed to address urban transportation networks where a non-negligible subset of the network links do not have real-time link volumes, and where that data is needed to populate other real-time traffic analytics. Computation is split between an offline calibration and a real-time estimation phase. The offline phase determines link-to-link splitting probabilities for traffic flow propagation that are subsequently used in real-time estimation. The real-time procedure uses current traffic data and is efficient enough to scale to full city-wide deployments. Simulation results on a medium-sized test network demonstrate the accuracy of the method and its robustness to missing data and variability in the data that is available. For traffic demands with a coefficient of variation as high as 40%, and a real-time feed in which as much as 60% of links lack data, we find the percentage root mean square error of link volume estimates ranges from 3.9% to 18.6%. We observe that the use of real-time data can reduce this error by as much as 20%.     

Transit investment and economic development

This paper describes the development of approaches to analysing the links between investment in transit and economic development. It indicates the need to bring together disparate approaches from urban economics and transportation economics to get a full understanding and uses recent results on agglomeration economies to present a more rigorous model of the wider economic benefits of transit investment. Although the evidence increasingly points towards identifiable benefits over and above those captured in conventional transport cost-benefit analysis, the chapter counsels against the assumption of simple rules.     

A statistical investigation of time-variant hull girder strength of aging ships and coating life

Risk- and reliability-based approaches are increasingly being applied in assisting inspection and maintenance planning. One of the keys to such approaches is properly predicting the hull girder strength (HG) of gradually degradated hull structures. The development has been limited by the lack of data on aging ships—validation of the developed methods has not been possible. To fill the gap of knowledge on hull strength of ships in service, this paper presents a database of as-gauged hull structures and a statistical study of the time-variant HG of tankers. The expanded data set was collected from 2195 as-gauged girth belts (transverse sections) of 211 single-hull tankers that were 12–32 years old. It was intended to (1) provide actual data on hull girder section modulus (HGSM) of tankers, (2) investigate the general trends of the change in the HG over ships’ service life, and (3) propose formulations for presenting time-variant HGSM and coating life.

The data set demonstrated a high variation of HGSM that changed over time. The mean value and standard deviation of HGSM loss were derived as functions of time. The probability density function (pdf) of coating life was also derived. Comparisons were made between previous studies on HG and the current data set. It was found that almost all previous studies showed much greater HG loss than what this database revealed. The refinement of existing calculations appears to be needed. The data set and statistical study were expected to form the basis for validating formulations of HG that are key components in risk- and reliability-based approaches.     

Engaging paratransit on public transport reform initiatives in South Africa: A critique of policy and an investigation of appropriate engagement approaches

A number of South African cities are planning integrated public transport networks that rely on the introduction of Bus Rapid Transit (BRT), in line with similar trends to expand or upgrade public transport services in emerging and industrialised urban transport markets around the globe. In addition, BRT in South Africa is being used as a mechanism to drive reform in the dominant yet highly fragmented paratransit sector, inspired by similar processes particularly in Latin American cities such as Bogotá, Mexico City, and Santiago de Chile. Thousands of paratransit operators would have to formalise their businesses, or merge into new or existing operator entities in order to participate in the new systems. There is, however, an absence of accessible business plans and regulatory regime proposals around which paratransit can be engaged to convince it to alter its current modus operandi. A large number of national, regional and local paratransit groupings have furthermore indicated their resistance to the planned networks on the grounds of insufficient consultation, an unclear future role in the system and employee redundancies. Should this deadlock not be resolved, it seems unlikely that the planned networks will be realised in the proposed timeframes, if indeed at all. This paper investigates the South African passenger transport policy framework that has contributed to the current deadlock, and explores appropriate approaches to engaging paratransit operators on a system of contracting, competition and ownership that recognises the sector’s aspirations and fragmented nature, yet contributes towards improved passenger transport services. It is the authors’ view that paratransit reform is a highly context-specific process, even at the sub-city level, and that this could prevent transferring paratransit regulatory and integration approaches across countries, and even cities in the same country, without adaptation to local conditions.     

氢燃料在铁道车辆的应用前景

以英国IC225车队为例,分析了氢燃料在铁道车辆上应用的技术要求,概述了氢燃料列车设计的可行性,并预测其在铁道车辆的应用前景.     

Active Railway Suspensions: Implementation Status and Technological Trends

The paper provides a comprehensive survey of active railway suspensions, covering both basic concepts and significant practical implications around the world. A critical review of technological opportunities, both current and future, is included, and the final section takes a speculative look at long term trends.     

城市环境中共享（街道）空间概念演变综述

通过综述城市设计与交通工程学科文献,从新西兰视角明确共享空间概念的起源和演变。综述过程包括研究公众期望变化背景下的公共道路空间的功能与使用以及如何与一些相互关联的街道设计方法(如交通稳静化和自适应道路)联系起来。这些方法从机动车时代初期就被用于最小化机动车影响。应用于城市活动中心的公共道路环境中的共享空间概念,正逐渐被城市规划师、交通工程师和管理部门所接受。共享空间不同于传统道路,它鼓励通过少量物理隔离使全体道路使用者合理地使用同一道路空间。为了以安全有效的方式实现共享空间,在设计上需要通过促进步行与骑行活动来降低机动车主导性,同时应将道路空间作为场所来利用而非仅仅出于其机动性与可达性目的。基于交通稳静化街道与共享空间在基础概念上的差异,认为共享空间由一些设计要素组成,若缺少这些要素,公共街道将难以对全体道路使用者发挥其真正的共享空间功能。     

Lights, camera and acoustics: Assessing macrobenthic communities at a dredged material disposal site off the North East coast of the UK

This study presents the results of a trial assessment based on a combination of sampling techniques at a dredged material disposal site located off the North East coast of the UK, over 2001 to 2004. The site was surveyed with a high-resolution sidescan sonar system producing a mosaic with 100% coverage of the survey area. Benthic communities and sediments were ground-truthed using a Hamon grab with a video camera. Additionally, the area was also sampled in 2003 with a Sediment Profile Imaging (SPI) camera, which complemented other techniques by providing in situ information on sediment quality, and biogenic activities. An assessment is made of the benefits of combining the results from conventional methods, principally using grab samples, with those from acoustic techniques and optical imaging devices to determine seafloor and macrobenthic conditions. This information has the potential to contribute to the enhancement of routine monitoring programmes within UK waters.