全自动智能运输系统的分布式递阶控制方法

针对动态环境中的全自动智能运输系统的控制问题,提出一种适用于该系统的分布式递阶控制方法。该方法以大系统递阶控制理论为基础,采用3级结构,包含组织级、协调级和执行级。分布式递阶控制方法在不同层次上分别处理全自动智能运输系统的车辆调度、车辆协调及车辆行为控制问题。组织级响应实时变化的运输需求,并由此确定无人驾驶车辆的调度命令。协调级负责化解系统内车辆之间的潜在冲突。执行级负责无人驾驶车辆的行为控制。仿真试验研究结果表明,较之传统的定时发车方式,对于全自动智能运输系统,采用分布式递阶控制的系统控制方法能够缩短乘客的平均等车时间并提高车辆的使用效率。     

上海集装箱运输的现状与发展思考

在调查上海集装箱港航企业基础上,分类地统计了有关上海集装箱运输的数据。基于对上海集运产业的认识,结合本次调查所掌握的实际情况,对上海集运产业的发展提出了若干建议。在软件建设方面,尽快形成综合开发队伍,提高管理系统软件的开发层次和开发速度;加快电子单证、电子签名等的技术研究与立法工作;开发更为完善的生产作业指挥系统。在企业发展战略方面,着重从稳定货源、加强合作、着力开拓三方面进行了论述。     

基于探测车技术和多级模糊模式识别的道路交通状态评价方法

提出了一种新的多因素道路交通状态评价方法,利用探测技术获取的探测车平均速度、拥堵系数、停车时间比例、加速度噪声和平均速度梯度作为交通拥堵表征量,采用VISSIM仿真方法确定出交通拥堵表征量的阈值,并应用多级模糊模式识别方法实现道路交通状态的评价过程。仿真结果表明:利用探测车技术和多级模糊模式识别方法可以准确方便地实现道路交通拥堵状态的评价,并且能够反映出评估时段内道路交通状态的变化。     

面向高速公路交通调度的动态数据融合

在高速公路交通动态数据融合需求分析的基础上,采用环形线圈和微波检测器建立多检测器动态数据的现场试验站,通过多检测器组合方式构建数据检测方案;应用基于自适应加权和改进BP神经网络的数据融合方法,建立交通动态数据融合模型,研究高速公路同一时间、相同断面的多检测器的数据融合。现场试验与检测数据分析表明：基于改进BP神经网络融合方法所获得试验数据的平均相对误差较微波和环形线圈各自的精度提高了10％-20％。     

Transport and equity in Latin America: a critical review of socially oriented accessibility assessments*

ABSTRACT

A growing concern for mobility-related social inclusion and equity is evident from both academic research and planning best practices. Scholarly research promotes accessibility as the main aim of transport planning, assuming it as the evaluative approach that better conveys how mobility contributes to individuals' well-being and participation in social life. Accessibility can be crucial to address the socio-spatial inequalities that characterise manifold settings across the world. Amongst them, Latin American countries have been keen in tackling such imbalances through mobility-related interventions, as the renowned cases of Curitiba, Medellin and Bogotá show. The widespread interest in mobility as both a cause and effect of social disparities has generated an increasing stream of work that examines Latin American settings through the lenses of accessibility. This paper aims at critically reviewing the growing scholarly works that, providing accessibility-based evaluations, has examined issues of transport and equity in Latin America. Proposing a novel conceptual framework that considers the underlying ethical stance, components of accessibility and implications for planning and policy, this work examines what approaches, features and indicators are present in the current literature, as well as what settings have been taken into consideration by scholarly research. Moreover, the review has an explicit operational interest, to define what indicators are relevant or missing to assess accessibility in the light of social concerns, as well as to consider the current and potential implications that such research findings have on transport planning and policy. The review highlights how a growing but still limited body of work has examined transport and equity in Latin America, suggesting academic, technical and operational avenues to enhance theoretical and practical approaches to the issue.     

Transport models, philosophy and language

The aim of this paper is to encourage debate about the nature of transport modelling. It does so firstly by considering the underlying philosophies of science (apparently) adopted by transport modellers, over a period of more than 50 years, from the 1950s until the present day. The conclusion is that a new philosophy of science needs to be developed, which is more in tune with how transport modelling is actually carried out (as opposed to how early transport modellers thought it ought to be carried out). It is recommended that such a new philosophy perceives transport modelling as a linguistic activity within the overall context of transport planning, which is in turn considered as a communication process. The paper outlines three main approaches that could be taken in this respect, analysing transport models from metaphorical, narrative and aesthetic perspectives. Conclusions are drawn upon the possible future research directions that might follow from the analysis provided in the paper, emphasising the importance of bringing formal philosophical thinking into transport modelling research and practice.

The provision of home to school transport in Northern Ireland

The provision of home to school transport is an important element of transport policy in local communities. This paper examines the provision of home to school transport in Northern Ireland. It reviews the nature of demand and provision, and the costs involved in providing the current system of home to school transport compared to other parts of the UK. In addition it also discusses issues surrounding the use of the statutory walking distance, safety on buses including the provision of ‘3 for 2’, standing on buses and seatbelts in Northern Ireland.     

Improvement in the estimation and back-extrapolation of CO2 emissions from the Irish road transport sector using a bottom-up data modelling approach

Road transport is a major source of CO₂ emissions in Ireland and accounts for almost 96% of the total CO₂ emissions from the transport sector. Following the recent adopted UNFCCC reporting guidelines on annual inventories [24/CP.19], this study applied the 2006 IPCC Guidelines for National Greenhouse Gas Inventories (2006 IPCC GLs) tier 3 approach to estimate CO₂ emissions from road transport at the vehicle category level, for the first time in Ireland. For this, disaggregated datasets were prepared based on year of vehicle registration and mileage since registration of the vehicle. Such an approach provided a more realistic national scenario in comparison to the use of average mileage degradation in emission calculations. This investigation comprised a recalculation of previous emissions estimates (1990–2012) and an estimation of CO₂ emissions in 2013 using a previously unavailable level of data disaggregation for vehicle mileage as well as using vehicle class specific data and an improved bottom-up estimation methodology in COPERT. Historic vehicle fleet data were restructured, annual mileage data were estimated in relation to the fleet data and back extrapolated using a regression approach.The results showed that the mileage degradation was not only subject to fuel technology, engine size, and age but also the emissions class and vehicle category. It was also observed that the disaggregated level of data provided a different CO₂ emissions split among the vehicle categories than that of previous estimations which were based on an aggregated level of data. Previous emissions inventories (1990–2012) were shown to have underestimated the share from diesel fuelled passenger cars by more than 56% in 2012. Diesel fuelled passenger cars were also found to account for the majority of CO₂ emissions from road transport activities in Ireland in 2013. The level and trend assessment showed that emissions from Euro-II and Euro-III classed vehicles especially for passenger cars, which have a significant contribution to the total emission in 2013 have caused an increase in fleet level emissions in Ireland. In addition, the results also showed that the emissions share from Light Duty Vehicles and Heavy Duty Vehicles were overestimated by previous investigations. This paper highlights the importance of the resolution of data used in emissions inventory preparation which may impact upon future projections and policy formulation. The findings of this investigation are also discussed in relation their implications for road transport policy, including carbon taxation and future policy options aimed at achieving EU emissions target in 2020.     

Speed limit laws in America: The role of geography, mobility and ideology

Speed limits had been centralized at the federal level since 1974, until decisions were devolved to the states in 1995. However, the centralization debate has reemerged in recent years. This paper conducts the first econometric analysis of the determinants of speed limit laws and State reactions after the repeal. By using mobility, geographic and political variables, our results suggest that geography - which reflects private mobility needs and social preferences -, is one of the main factors influencing speed limit laws, together with political ideology. Furthermore, we identify the presence of regional and time diffusion effects. By presenting first evidence on policy determinants, we provide a better understanding of the formulation of the heterogeneity of speed limits in US and offer implications for the debate on centralization and decentralization of transport policy.     

Efficiency measurement in public transport: Are findings specification sensitive?

The need to measure transit system performance along with its various dimensions such as efficiency and effectiveness has led to the development of a wide array of approaches and vast literature. However, depending upon the specific approach used to examine performance, different conclusions are oftentimes reached. Using data from 15 European transit systems for a ten year time period (1990-2000), this paper discusses three important transit performance questions; (i) Do different efficiency assessment methodologies produce similar results? (ii) How are the two basic dimensions of transit performance, namely efficiency and effectiveness, related? and (iii) Are findings regarding organizational regimes (public operations, contracting and so on) sensitive to the methodological specifications employed? Results clearly indicate that efficiency scores and associated recommendations are sensitive to the models used, while efficiency and effectiveness are - albeit weakly - negatively related; these two findings can have far reaching policy implications.