Morning commute problem considering route choice, user heterogeneity and alternative system optima

This paper extends the bottleneck model to study congestion behavior of morning commute and its implications to transportation economics. The proposed model considers simultaneous route and departure time choices of heterogenous users who are distinguished by their valuation of travel time and punctual arrival. Moreover, two dynamic system optima are considered: one minimizes system cost in the unit of monetary value (i.e., the conventional system optimum, or SO) and the other minimizes system cost in the unit of travel time (i.e., the time-based SO, or TSO). Analytical solutions of no-toll equilibrium, SO and TSO are provided and the welfare effects of the corresponding dynamic congestion pricing options are examined, with and without route choice. The analyses suggest that TSO provides a Pareto-improving solution to the social inequity issue associated with SO. Although a TSO toll is generally discriminatory, anonymous TSO tolls do exist under certain circumstances. Unlike in the case with homogenous users, an SO toll generally alters users’ route choices by tolling the poorer users off the more desirable road, which worsens social inequity. Numerical examples are presented to verify analytical results.     

Developing sustainable transport for the next generation: The need for a multi-sector approach

While some countries have made progress in encouraging more sustainable transport and travel patterns, there are limits as to how far this can be taken simply by looking at the decarbonisation of transport systems, since most travel is a derived demand and hence is strongly influenced by decisions taken by public and private sector agencies in different sectors. The paper first identifies some of the major non-transport sector influences on different aspects of travel behaviour. It then looks in more detail at changing patterns of grocery shopping over the last half century, and how these changes have been associated with new non-transport technologies and accompanying developments in business and social practices. Next, a simple visual spreadsheet tool is presented, that has been used by agencies to explore the main cross sector impacts (both positive and negative) of their major location and operating decisions. Finally, the paper proposes three ways in which cross sector synergies can be encouraged: (i) by giving each sector or major organisation responsibility for all CO₂ emissions associated with its activities, including those generated by the travel of its staff, customers, suppliers, etc.; (ii) by making major policy making within government a cross sector activity; and (iii) by developing a common, cross sector appraisal methodology for assessing the full range of impacts of policy proposals.     

嵌岩桩竖向承载力的探讨

针对规范中嵌岩桩竖向承载力的计算方法,所存在的问题和不合理之处,提出了用灰色预测系统理论对嵌岩桩单桩承载力的预测。根据灰色系统理论,建立了桩基工程GM(1,1)模型,结合桩基试桩实践,所得预测结果与实际结果吻合较好,经过精度检验,证明精度较高,为桩基工程承载力预测提供了一种可靠的理论方法。     

Applying social marginal costs pricing to the road sector

This chapter, following the results of the case studies analyzed in the Enact project, will identify and analyze the implications of the possible application of SMCP in PPP’s in the road sector. The main issues analyzed include SMCP revenue formation and its ability to finance the PPP. The paper will focus on market and competition issues like: 1) the problems due to mispriced substitutes; 2) the interdependencies between the tolls and the capacity of different road infrastructures when these are competing for the same demand; 3) since short run social marginal costs do not repay for the investments costs (except in special cases), in the case tolls should cover also the investment costs this will lead to totally different pricing schemes between roads in a same area, with problem of demand shift toward cheaper existing infrastructures, therefore increasing the problem of cost recovery. The incentives caused by the introduction of prices based on SMC’s are also investigated.     

Applying social marginal cost pricing in rail PPPs: Present state, drawbacks and ways forward

The application of social marginal cost pricing (SMCP) in PPP's in the railway sector faces several challenges. We examine in detail the practical applicability of SMCP in railway PPPs from the perspectives of cost accounting and effectiveness of SMCP towards the allocative efficiency goal, addressing the likely drawbacks in conciliating the welfare objectives of SMCP with the objectives of project financing (cost recovery) and value for money that justify the realization of PPP's. To this end, we combine theoretical analysis with the observation of empirical results of a case study. We split the analysis per type of private service provision, which can be for service operation or infrastructure management. For infrastructure management, we recommend splitting the operator remuneration and the track access charges. For service operation, we argue that the correct decision on source of funding of the service operator should depend on the characteristics of the contract.     

How can the maritime industry meet Sustainable Development Goals? An analysis of sustainability reports from the social entrepreneurship perspective

Sustainability Development Goals (SDGs) are a comprehensive agenda agreed upon globally that aims to stimulate actions towards economic, environmental and social sustainability. Being one of the key stakeholders, the international maritime industry plays an important role in contributing to global sustainability. By applying the concept of social entrepreneurship (SE), this study aims to examine (1) the basic and extended responsibilities (SDG 1–SDG 16) and (2) the potential collaborations within the value chain (SDG 17) concerning SDG implementation in maritime industry. To achieve these, we conduct a content analysis of sustainability reports published by container shipping liners and terminal operators from 2016 to 2019. More specifically, manual text classification is adopted to categorise the text content of sustainability reports based on 17 SDGs, and automatic text mining is employed to further identify the key roles of maritime industry related to each SDG. A unified framework is proposed, which points to varied motives and levels of comprehensiveness of the sustainability efforts by the maritime industry. This framework reveals the theoretic process of maritime industry's transitional involvement in sustainability from the SE perspective. It also creates managerial implications regarding the resource allocation strategies by maritime industry in meeting SDGs.     

Social networks,social influence and activity-travel behaviour: a review of models and empirical evidence

ABSTRACT

The study of social networks in activity-travel research has recently gained momentum because social activities and social influence were relatively poorly explained in activity-based models of travel demand. Over the last decade, many scholars have shown interest in identifying personal social networks that constitute an important source of explanation of activity-travel behaviour. This paper seeks to review two research streams: social networks and activity-travel behaviour, and social influence and travel decisions. We classify models, summarise empirical findings and discuss important issues that require further research.     

试论老舍小说对社会意识的关注

文章通过对老舍小说文本的研究,发现老舍先生通过比较或陈述的方法在自己的作品中或多或少地表现了他对社会意识的关注。老舍的小说所关注的社会意识主要体现在全社会整一的＂官本位＂思想、愚民教育下的＂顺民＂意识、国民精神和国民人格等方面。