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Population aging is happening in many places, such as on the Chinese mainland and in Hong Kong. Hong Kong, with the second-highest percentage of older adults in Asia, is among the world's fastest-aging societies. Moreover, the city has very high transit patronage: transit trips constitute approximately 90% of all trips. Given the significance of transit in Hong Kong, improving transit services for older adults is of substantial importance. In light of this, based on the data of transit satisfaction (or perception) collected by a questionnaire survey in March 2015 (N=613), this study adopts the entropy weight method to determine the importance weights of an array of transit service quality attributes (e.g., seat availability and travel stability). Then, it performs an index-based importance-satisfaction (I-S) analysis using the outcome of the previous step as a basis to determine priorities for transit service improvement. The results show that in the view of older adults, three service quality attributes in need of improvement are seat availability, waiting conditions, and service frequency. Accordingly, the paper puts forward policy implications for further implementation. [ABSTRACT FROM AUTHOR]

This study aims to determine how tourists perceive the quality of a walking system in a traffic-free destination. We conducted a questionnaire survey on tourist satisfaction with attributes and overall performance of the walking system at Kulangsu (China) in October 2017 and February 2018. We developed an ordered probit model to evaluate the relative importance of each attribute by employing the pooled cross-sectional data. Results show that the attributes that need an enhancement in the view of tourists are the level of crowding and cleanliness. The two attributes have not been pointed out in previous literature. Accordingly, policy implications are proposed. The findings enhance our understanding of tourist satisfaction with the walking system. [ABSTRACT FROM AUTHOR]

Numerous cities are undergoing the ageing of populations. Developing a transport system that incorporates mobility needs, preferences, and demands of elderly people is crucial to such a demographic shift. Understanding the travel behavior and characteristics of elderly people is the first and foremost step towards this goal. In stark contrast with Western car-dominant places, numerous East Asian modern cities (e.g., Hong Kong, Beijing, and Shanghai) have high levels of public transportation use. Experience gained from existing studies in the West cannot be applied to Hong Kong, a typical transit-dependent city. In light of this, based on the 2011 Travel Characteristic Survey data and Poisson and negative binomial regression models, this study identifies factors that significantly affect the number of daily trips taken by (or trip frequency of) elderly people in Hong Kong. The paper finds that both socio-demographic (e.g., age and housing type) and built environment characteristics significantly affect the trip number of elderly people. Interestingly, it is determined that car availability does not play a significant role in the trip generation process, but public transportation accessibility truly matters. This outcome remarkably differs from findings in Western car-dominant cities. Moreover, to discern whether the elderly are a homogenous group, this study estimates separate models for the young elderly (aged between 60 and 74) and the very old (aged 75 or above). It is observed that the effect of public transportation accessibility on elderly mobility varies among elderly subgroups: public transportation accessibility significantly affects the trip frequency of the young elderly, but not that of the very old. Finally, a multitude of policy measures with the aim of upgrading elderly mobility is proposed. [ABSTRACT FROM AUTHOR]

The escalating prevalence of extreme heat events has intensified scholarly interest in understanding the nexus between urban built environments and extreme heat. This study focuses on the central urban areas of Chengdu and Chongqing, sizable Chinese cities that share a common building climate zone but are divergent in topography and landform (i.e., plain versus mountainous). Leveraging spatial regression, XGBoost, and Shapley additive explanation techniques, we scrutinize the spatial effects, relative importance, and interactive impacts of two-dimensional and three-dimensional (2D/3D) built environments on land surface temperature (LST). The results indicate that: (1) 2D/3D variables exert significant effects on LST, with the cooling effect of the 3D green view index outweighing that of the 2D normalized difference vegetation index (NDVI). (2) The overall relative importance of 3D variables on LST is greater than that of 2D variables in both Chengdu and Chongqing. (3) The 3D variables have particularly strong impacts on LST in mountainous cities, which are 6.21 % higher than those in plain cities. (4) 2D/3D variables interactively influence LST. For instance, LST drops in Chengdu when floor area ratio (FAR) is above 1.5 and NDVI is below 0.53, as well as when FAR is less than 1 and NDVI is greater than 0.53. Our findings provide support and recommendations for location-specific sustainable urban development and effective heat adaptation strategies. • Leverage machine learning and Shapley additive explanation (SHAP). • The most powerful cooling is delivered by FAR. • The overall importance of 3D variables is greater than that of 2D. • The impact of 3D variables is higher in mountain cities compared to plain cities. • There are interactive effects between 2D and 3D built environment variables. [ABSTRACT FROM AUTHOR]

Many cities in the developing world have implemented the driving restriction policy to address transport-related problems (e.g., traffic congestion and air pollution). However, the evidence of the effectiveness of this policy exhibits significant regional variations. Using an abrupt policy change in Chengdu, namely the tightening of the driving restriction policy by expanding the regulated area, as a natural experiment, this study provides new evidence of the effects of driving restrictions based on the difference-in-differences approach. On the one hand, we leverage the temporal variation in the number of cars being banned on roads due to the traditional superstition (number 4) in China and the spatial variation in restricted and unrestricted areas to verify the causal effect of driving restrictions on air quality. We find that policy tightening has caused a significant reduction in major air pollutants of PM 2.5 , PM 10 , CO, NO 2 , and SO 2 and a decrease in the composite air quality index in a year after policy tightening. Furthermore, we observe that policy tightening has resulted in an increase in the demand for housing units located near subway stations in areas subject to the new driving restriction policy. This study affirms the effectiveness of driving restrictions in the absence of confounding influences from other travel demand management strategies. Accordingly, in the face of restrictions on private car use, it is important to increase the supply of public transport and affordable housing with good access to public transport. [ABSTRACT FROM AUTHOR]

An easily applied and efficiently exploited approach was proposed for the prediction of inter- and intra-annual land surface temperature (LST) in a city's central zone. Chengdu is chosen as the study area to demonstrate the applicability of the novel approach. Built-up areas were extracted using Landsat images in 2008, 2013, and 2019 and projected for 2030 using the cellular automata-Markov chain model, indicating that built-up areas grew nearly 109% during 2008–2019 in Chengdu and will continue to grow up to 2030. Employing the multiple linear regression, the LST of built-up areas in 2019 was predicted using the normalized difference built-up index (NDBI) and the mean LST of its surrounding pixels (LST-R3) in 2013 (R2 = 0.981). The model's intra-annual application for 2019 showed a mean LST deviation of 0.93 °C. According to the model's inter-annual application, the projected LST of the built-up areas in 2030 will increase to 36.5 ± 2.0 °C. The results can contribute to achieving a thermally comfortable urban environment by providing insights into the impact of urban expansion on the urban heat island (UHI) phenomenon under the limited availability of continuous LST data. • High cloud coverage in Chengdu City limits continuous satellite-based monitoring of land surface temperature (LST). • To overcome this constraint, an integrated urban growth and LST prediction approach is proposed. • The training of the LST model involves the utilization of NDBI and LST of surrounding pixels. • The performance of the model in predicting inter- and intra-annual LST is satisfactory. • The model contributes toward creating a thermally comfortable urban environment. [ABSTRACT FROM AUTHOR]

Ecosystem services (ES) concepts and approaches have become more appealing to practice, such as municipal/urban planning, environmental policies and governance to address sustainable development. Inclusion of this concept in the planning or policy discourses is the first step for further implementation on the ground. Using China's capital, Beijing, as the case study, this article analyzes how ES (or similar concepts) have permeated China's urban development history since 1949 when the New China was established and how this has to be with China's urban green space development. The results show: (1) There were no explicit references to "ecosystem services" per se, but overlapping concepts such as "functions", "values" and "benefits" can be found in planning documents and, importantly, the lack of the concept per se has not affected the detailed services that emerged in all plans. (2) Among the three ES sections, only cultural services run from the beginning to end although the included services kept changing. Other sections show considerable variation and less continuity – the focal services of each stage changed over time. (3) Through the ES lens, some general patterns regarding China's urban development can be found such as regulation services gradually become valued for their own sake. The patterns found in Chinese planning documents are then compared with some western regions. This study reveals limitations of the past and opportunities for the future to inform urban development decision-making. Adaptation of old and incorporating new ES concepts can improve the quality of plans and foster cities' ability to learn from past patterns for future sustainability. • Analyzing how ecosystem services (ES) have permeated China's urban development. • The study is based on coding and analyzing discourse and document contents. • Through ES lens, general patterns can be found in China. • Cultural services play a pivotal role in urban development history. • Opportunities exist in the "non-mainstream" ES to incorporate more ES into plans. [ABSTRACT FROM AUTHOR]

• Effects of future climatic uncertainties on building retrofit decisions are estimated. • Life-cycle economics and carbon emissions are selected as the multiple objectives. • Future climatic uncertainties alter optimal values of some building retrofit measures. • Optimal infiltration standard and insulation options are susceptible to future climate. • Optimal glazing materials and shading options are not susceptible to future climate. Energy consumption of and carbon emissions from buildings, which substantially depend on outdoor climate conditions, may be susceptible to future climate change. However, how future climatic uncertainties affect decision-making regarding building energy retrofits is unclear from the life-cycle analysis perspective. This study used typical high-rise public rental housing buildings in subtropical Hong Kong as a case study to consider future climatic uncertainties under representative concentration pathway scenarios and in different general circulation models to estimate their effect on multi-objective building retrofit decisions considering trade-offs among different objectives, namely, life-cycle economics, life-cycle carbon emissions, and operational energy use impacts. The results indicate the significant influence of future climatic uncertainties on the optimal values of building energy retrofit measures. The passive house infiltration standard and thick (0.06–0.1 m) polyurethane foam insulation can be recommended for long-term future climatic conditions (RCP8.5–2065s). By contrast, optimal values of glazing materials, horizontal shading projection factors, and window-to-wall ratio are not susceptible to future climatic uncertainties. Uncertainties from different general circulation models are another notable factor affecting optimal values and retrofit options. This study reveals the importance of considering future climatic uncertainties when deciding optimal values and selecting building energy retrofit options. [ABSTRACT FROM AUTHOR]

• Use mobile phone signaling data to assess urban vitality. • Call for temporally and spatially varying policies for urban vitality enhancement. • The spatial distribution of urban vitality is clustered and polycentric. • Urban vitality varies considerably throughout the day. • The effects of metro accessibility are more evenly distributed on weekends. Urban vitality has long been a focus of urban planners and designers. This study portrays the spatiotemporal patterns of urban vitality in Chengdu, China, on weekdays and weekends and examines their relationship with a set of factors using spatial regression and geographically weighted regression models. The results reveal that the spatial distribution of urban vitality displays a clustered and polycentric pattern, which can be attributed to urban spatial structure. Urban vitality varies considerably throughout the day on weekdays and weekends, and it consistently decreases as the distance to the city center increases. Furthermore, weekday vitality is much more predictable (less random) than weekend vitality, indicating that human activity patterns present higher regularity on weekdays than on weekends. The normalized difference vegetation index (NDVI), road density, the number of residential facilities, and land-use mix have positive influences on urban vitality on weekdays and weekends, while the distance to the metro station has negative influences. The influences of NDVI on urban vitality in the city center are negative on weekdays but become positive on weekends. The influences of the distance to the metro station are more homogeneously distributed on weekends than on weekdays. Finally, this study calls for temporally and spatially varying policies for urban vitality enhancement. [ABSTRACT FROM AUTHOR]

Optimizing the built environment helps alleviate the adverse impact of extreme heat on public health and sustainable urban development. To this end, this study measured the daily land surface temperature (LST) in August 2022 (when extreme heat occurred) in Chengdu and introduced the 3D street view characteristics extracted from street view images. By employing OLS and spatial regression models, we probed the combined effects of 2D and 3D built environments on LST and their relationships under disparate circle spaces. The results show that: (1) compared with the 2D built environment, the 3D built environment presents a superior impact on LST. (2) urban land use that is 3D, compact, and has a high-floor area ratio diminishes LST, as evidenced by the finding that floor area ratio (FAR) reduces LST, but building density enhances it. (3) the green view index exhibits a stronger cooling effect than green space areas. (4) the built environment beneath distinct circle spaces displays a spatially varying impact on LST. For example, FAR is positively correlated with LST in the urban center, while in the urban periphery, it is prominently negative. Our empirical findings are conducive to formulating strategies from both 2D and 3D built environments for the formation and implementation of healthy urban design and development. • In 2022, extreme heat has risked public health and urban sustainable development. • 3D, rather than 2D, environment has superior impacts on LST. • FAR reduces—whereas building density increases—LST. • The green view index shows a stronger cooling effect than that of green space area. • Built environment and LST have spatially varying impacts in distinct circle spaces. [ABSTRACT FROM AUTHOR]

• Temporal heterogeneity exists in the associations between metro ridership and the built environment. • Built environment variables have non-linear and threshold effects on metro ridership. • Distance to the city center and population density are strong predictors of metro ridership in the morning peak hour. • Employment density, enterprise density, and road density are strong predictors in the evening peak hour. • Critical TOD planning parameters are identified. The metro is the backbone of the transport system in many cities. Analyzing the built-environment correlates of metro ridership is crucial for transit-oriented development (TOD) planning and practice. Although numerous studies went along this line, they have rarely considered the non-linearity and temporal heterogeneity in the association of metro ridership with the built environment. After collecting transit smart card data, geo-data, and mobile phone signal data, this study adopts the random forest model to reveal the complex association of hourly metro ridership in November 2019 in Chengdu (China) with the built environment in three times of day (i.e., morning peak, noon off-peak, and evening peak hours). Notably, the contribution of several variables, such as the number of station entrances/overpasses and parking density, has rarely been considered in the literature. The results confirm the presence of non-linearity and temporal heterogeneity in the aforementioned association. Access to the city center and population density are strong predictors of metro ridership in the morning peak hour, whereas employment density, enterprise density, and road density are strong predictors in the evening peak hour. There are great differences in the correlates of metro ridership in different periods. Critical TOD planning parameters are also identified from the partial dependence plots obtained from random forest modeling. [ABSTRACT FROM AUTHOR]

• Short EBSS trips mainly substitute walking and the BSS. • Long EBSS trips mostly substitute cars, buses, and the subway. • The integration of the EBSS and transit has reduced carbon emissions. • The CO 2 emissions per km are 19.47 g. • The EBSS has saved 75.52% of CO 2 emissions. This paper presents a quantitative analysis of the mode substitution and usage-phase carbon emission impacts of the electric bike-sharing system (EBSS) on urban transportation using self-administrated survey data and EBSS operating data. The substitution probabilities of a given EBSS trip for different transport modes is determined using the Bayesian inference method. Emission impact is measured by comparing the current emissions to those generated by other transport modes without the EBSS. Remarkably, the partial-trip substitution impact of the EBSS on car travel is investigated, where the EBSS serves as a connection to public transit. The results show that the EBSS barely generates new trips; most short-distance EBSS trips were transferred from walking and conventional bike-sharing, and most long-distance trips were shifted from cars, buses, and the subway. Around 5% of EBSS trips less than 2 km were transferred from the car by integrating with public transit while accounting for over half of the emission reduction. Based on our method, the CO 2 emissions per km of EBSS are 19.47 g, with 6.91 g generated by e-bikes due to electricity consumption and 12.56 g by trucks for battery swapping and bike relocation. The studied EBSS has saved 75.52% of CO 2 emissions that other transport modes could have generated. [ABSTRACT FROM AUTHOR]

Previous studies extensively examined the role of accessibility to metro in shaping house prices but largely overlooked the contribution of accessibility by metro. In addition, limited studies examined the moderating effect of COVID-19 on the price effects of to-metro and by-metro accessibility. Based on multilevel hedonic price and quantile regression models, this study scrutinizes the association between to-metro accessibility, by-metro accessibility, and house prices in Chengdu, China, and examines the moderating role of COVID-19 in this association. We show that by-metro accessibility significantly influences house prices. COVID-19 significantly influences the value of to-metro accessibility but marginally affects that of by-metro accessibility. The value of to-metro accessibility is disproportionately affected by the pandemic. Specifically, small or low-priced houses are less affected than big or high-priced houses. In other words, the flattening of the to-metro price gradient is more discernible for big or high-priced houses. The changing preference of residents has also been verified by the decreases in house transaction volume in metro-adjacent areas. [ABSTRACT FROM AUTHOR]