The threat of global climate change has caused the international community to pay close attention to atmospheric levels of greenhouse gases such as carbon dioxide. Transportation sector carbon dioxide emissions efficiency (TSCDEE) is a key indicator used to prioritize sustainable development in the transportation sector. In this paper, the epsilon-based measure data envelopment analysis model with undesirable outputs is applied to estimate TSCDEE for 30 provinces in China from 2010 to 2016. We also analyze influencing factors using the spatial Durbin model. Research shows that the overall TSCDEE of the Chinese provinces studied was 0.618, indicating that most regions are still in need of improvements. The provinces with the highest TSCDEE are located in developed coastal regions of China. This study shows that factors such as transportation structure, traffic infrastructure level, and technological progress have prominent positive effects on TSCDEE, while both urbanization level and urban population density exert significantly negative effects on TSCDEE. The findings should have a far-reaching impact on the sustainable development of global transportation.

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The energy-saving renovation of an existing building is a critical strategy in achieving a longterm energy goal in the Chinese context. However, in China, building energy renovation projects are subjected to quality failures resulting in energy wastage, a decrease in the energy efficiency of the project, an increase in project cost, and thus negatively affecting the overall performance of the renovation projects. In order to avoid them happening in the future, it is essential to find and analyse the causes of quality failures in energy-saving renovation projects. Therefore, using a four-step process, this research aims to deepen the understanding of the causes of quality failures in energy-saving renovation projects of the existing residential buildings. The first and second steps are to identify and analyse the quality failures and their causes. The deeper insights from a quality management perspective are explored in the third step. The fourth step is to investigate how the actors and their interactions affect and cause quality failures during the renovation policy implementation process. This research mainly concludes the causes of quality failures in the building energy renovation projects. It is important to state that most of the quality failures can be avoided at the management level. Some external causes originated at a policy level and outside the project. The findings of this research would be valuable for policy-makers and project coordinators both for predicting and avoiding quality failures and for developing proper action and policy interventions to ensure successful building energy renovations in the future.@en

To be successful, energy renovation construction programs in northern China require both proper understanding of the causes of quality failures and effective strategies for renovating existing residential buildings for energy savings. However, surprisingly, although in recent years more attention has been focused on studying quality failures and reducing their causes, such failures still frequently occur in building energy renovation projects. In practice, the causes are not isolated, but rather, stem from complex correlations that impede high-quality performance. Due to their neglect of the causal relationships among these factors in quality failures, project coordinators have been unsuccessful in managing the quality of construction projects. Considering a network of different causes, this work reports on efforts to identify and manage the causes of quality failures in construction processes. A new understanding of the nature of these causes was achieved by considering four sources of data: literature review, opinions of experts, interpretive structural modeling (ISM), and focus groups. Our analysis shows that not only do many causes directly influence construction quality in building energy renovation projects, but also these causes interact with each other. It is noteworthy that external causes remain associated with all internal causes. Drivers of these causes are lack of experienced project managers, unauthorized changes in design documents, incomplete building information in projects, and poor onsite coordination; eliminating them enables solutions to a number of other internal causes. Finally, solutions are proposed to improve the current situation. These solutions fall into the categories of people, materials and equipment, design, and organization, based on the quality management process. The findings of this work provide valuable information for helping both policy makers and practitioners adopt effective policies and measures to manage the construction quality of building energy renovation projects.

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Building energy renovations can effectively improve the environmental performance and energy sustainability of existing buildings. From 2007 onwards, the Chinese government has promoted energy-saving renovations of existing urban residential buildings. Nevertheless, various quality failures happen during the construction period in energy-saving renovation projects of residential buildings. Yet, the causes and their characters remain largely unknown. Through a literature review, this paper investigates the causes of quality failures. Validated through experts’ interviews, a total of 18 causes were identified in building energy renovation projects. These causes were analyzed from two main aspects: the importance of a cause (related to impact and frequency), and the level of effort required to address a cause (related to origin and scale), using both a questionnaire survey and a focus group. The results indicate that the critical causes of quality failures are working under high-cost and high-time pressure, adverse natural conditions, fraud of construction companies, incomplete construction site survey, poor checking procedures of supervisors, poor operational skilled workers, inadequate equipment performance, lack of experienced project managers, and incomplete building information in projects. The causes were classified as external and internal causes of building energy renovation projects. The outcome of this paper should aid policy makers and project coordinators to focus on critical causes of quality failures, and to develop effective actions and policy interventions to achieve successful renovation projects with high-quality performance@en

Building energy renovations contribute significantly to energy sustainability and environmental protection. These advantages have increased the importance of renovating existing residential buildings in many countries. In China, the government has supported the energy-saving renovation of existing urban residential buildings since 2007. However, quality failures, which do not meet the technical requirements, occur during construction processes in building energy renovation projects. Although quality failures are regarded as a crucial problem in building energy renovation projects, the identification of quality failures and their sources, likelihood, impacts, and causes remain mostly unknown. This paper investigates the nature of quality failures in building energy renovation projects. A total of 25 quality failures were first identified through five cases, and interviews with six experienced construction professionals in China. A questionnaire survey was further conducted to evaluate the frequency of quality failures. The results show the nature of quality failures that arise during construction and their sources, occurrence frequency, causes, and impacts. The research reveals that quality failures are caused by defaults by workers; inadequate checking procedures; incomplete construction site surveys; inaccurate design work; fraud of construction companies; and inefficient cooperation between different departments. Above all, the behaviors of the main actors are responsible for poor construction quality. Additionally, emphasis on quality control during the renovation preparation stage is critical to ensure that quality failures are reduced in numbers and severity.@en