Search Results (591)

Rapid development and scale expansion of cities are the core characteristics of the urbanization process, which effectively promote the formation of agglomeration economies, infrastructure sharing, and social mobility improvement. However, it also brings various negative effects such as unequal public services, traffic congestion, and environmental pollution. The principle of isobenefit urbanism proposes that walking accessibility of various service facilities is an important indicator for measuring whether a city is livable, fair, and sustainable. This study specifically examines the impacts of environmental factors on the implementation of isobenefit urbanism in the central urban area of Beijing, a megacity. By obtaining open-source data and performing ArcGIS (10.8.1) analysis, using 183 blocks in Beijing’s core area, we normalized Strava pedestrian heat by road area and regressed it on 12 built environment indicators. The final model (R = 0.650, R² = 0.422, and adjusted R² = 0.381) identifies five significant predictors: block area (β = 0.215, p = 0.001) and average building height (β = 0.299, p = 0.012) are positively associated with walking heat, while building density (β = −0.235, p = 0.003), intersection density (β = −0.321, p < 0.001), and average distance to bus stop (β = −0.196, p = 0.003) are negatively associated. Land use mix and facility supply show positive but nonsignificant effects after controls. These estimates provide actionable levers for isobenefit urbanism in megacity cores. Full article

With the rapid expansion of urban areas, short naturally ventilated traffic tunnels (NVTTs) have become prevalent in modern cities. However, their enclosed design and inadequate ventilation often lead to the accumulation of vehicle emissions, especially during peak traffic periods, which poses significant threats to public health. Previous studies have shown that airflow in such tunnels is caused by ambient crosswinds (ACWs), which contribute to the dilution of pollutants. Based on this, a geometrical model including traffic tunnels belonging to a complex traffic system of the Second Ring Road in Wuhan City was established, followed by a mathematical model describing the fluid flow and pollutant transformation. The current flow characters and pollutant dispersion mechanism of CO and NO_X were analyzed. Among them, the number and speeds of vehicles are measured to calculate the strength of the pollutant source. Then, the data was set as the initial contaminant source strength in Ansys Fluent 14.0 to compute the pollutant dispersion of the whole domain. The results indicate the following: (1) The airflow direction inside the tunnel varies with changes in ambient wind direction and wind speed. Specifically, variations in ambient wind direction result in changes in airflow direction in both tunnels. In contrast, changes in wind speed do not affect the airflow direction in both tunnels; only in the downstream tunnel does the airflow direction change with increasing westward wind speed. By comparison, in the upstream tunnel, the airflow direction remains unchanged regardless of the westward wind speed; (2) Pollutant accumulates along the downstream airflow in both the tunnels; (3) The mass fraction level of contaminate stratification differs along the tunnels. The pollutant tends to form y-component layering near the upwind opening and x-component stratification at the downwind opening of the two tunnels. Full article

Deploying public EV charging infrastructure while balancing efficiency, equity, and implementation feasibility remains a key challenge for sustainable urban mobility. This study develops an integrated, grid-based planning framework for Wuhan that combines attention-enhanced ConvLSTM demand forecasting with a trajectory-derived, rank-based accessibility index to support equitable network expansion. Using large-scale charging-platform status observations and citywide ride-hailing mobility traces, we generate grid-level demand surfaces and an accessibility layer that helps reveal structurally connected yet underserved areas, including demand-sparse zones that may be overlooked by utilization-only planning. We screen feasible grid cells to construct a new-station candidate set and formulate expansion as a constrained three-objective optimization problem solved by NSGA-II: maximizing demand-weighted neighborhood service coverage, minimizing the Group Parity Gap between low-accessibility populations and the citywide population, and minimizing grid-connection friction proxied by road-network distance to the nearest power substation. Practical deployment plans for 15 and 30 sites are selected from the Pareto set using TOPSIS under an explicit weighting scheme. Benchmarking against random selection and single-objective greedy baselines under identical candidate pools, constraints, and evaluation metrics demonstrates a persistent coverage–equity–cost tension: coverage-driven heuristics improve demand capture but worsen parity, whereas equity-prioritizing strategies reduce gaps at the expense of coverage and feasibility. Full article

The durability of concrete in immersed tunnels is critically influenced by the coupled effects of stress, seepage, and chemical erosion, particularly in inland water environments. However, the spatio-temporal evolution of mechanical property degradation under such multi-field coupling remains insufficiently quantified. Unlike previous studies focused on “load-ion” or “hydraulic pressure-ion” dual coupling, this work introduces a complete stress–seepage–chemical tri-coupling that incorporates the critical seepage effect, representing a fundamental expansion of the experimental scope to better simulate real-world conditions. This study investigates the degradation mechanisms of concrete in the Shunde Lungui Road inland immersed tunnel subjected to such coupled erosion. A novel aspect of our approach is the application of the micro-indentation technique to quantitatively characterize the spatio-temporal evolution of the local elastic modulus at an unprecedented spatial resolution (0.5 mm intervals), a dimension of analysis not achievable by conventional macro-scale testing. Key findings reveal that the mechanical properties of concrete exhibit an initial enhancement followed by deterioration. This behavior is attributed to the filling of pores by reaction products (gypsum, ettringite, and Friedel’s salt) in the short term, which subsequently induces microcracking as the volume of products exceeds the pore capacity. Furthermore, increasing hydro-mechanical loading significantly accelerates the erosion process. When the load increases from 1.596 kN to 3.718 kN, the influence range of elastic modulus variation expands by 9.2% (from 5.186 mm to 5.661 mm). To quantitatively describe this acceleration effect, a novel load-acceleration erosion coefficient is proposed. The erosion rate increases from 0.0688 mm/d to 0.0778 mm/d, yielding acceleration coefficients between 1.100 and 1.165, quantifying a 10–16.5% acceleration effect beyond what is typically captured in dual-coupling models. These quantitative results provide critical parameters for employing laboratory accelerated tests to evaluate the ionic erosion durability of concrete structures under various loading conditions, thereby contributing to more accurate service life predictions for engineering structures. Full article

Road transport constitutes a crucial element of the European economy, but it also generates significant external costs. In the process of reducing the impact of road transport on the environment and society, numerous actions are being undertaken to implement the concept of sustainable transport development in the Member States of the European Union. A key measure in this area is the introduction of low- and zero-emission propulsion systems in vehicles intended for passenger and freight transport. This article focuses on electric vehicles powered by battery energy storage systems. An essential component of these efforts is the development of alternative fuels infrastructure, which is expected to enable the operation of such vehicles by providing access to battery charging facilities. The development of infrastructure in the form of electric vehicle charging stations, initially concentrated in urban areas, has been extended to the network of European roads. The driving force behind this expansion is the European Parliament and the Council of the EU, which, on the basis of the Alternative Fuels Infrastructure Regulation (AFIR), stimulate the development of alternative fuels infrastructure along the TEN-T network. The aim of the article is to present selected challenges related to the electrification of road transport infrastructure in the context of the sustainable transport development concept and the construction of alternative fuels infrastructure along the TEN-T network. The research focuses on forecasting the demand for alternative fuels infrastructure along the A1 and A2 motorways, which form part of the TEN-T network within the territory of Poland. The research process stems from the implementation of the AFIR in the EU Member States. Full article

With the rapid expansion and aging of global road networks, cold recycled mix asphalt (CRMA) has gained significant attention as a sustainable pavement rehabilitation technology. However, the road performance of CRMA is highly sensitive to material composition and curing conditions, making accurate performance prediction challenging. This study develops machine learning (ML) models to predict two critical performance indicators: dynamic stability (DS) for high-temperature stability and indirect tensile strength (ITS) for low-temperature crack resistance. Four ML algorithms, Artificial Neural Network (ANN), Extreme Gradient Boosting (XGBoost), Random Forest (RF), and Support Vector Regression (SVR), were trained on a comprehensive dataset of 436 samples. A genetic algorithm (GA) was employed to optimize model hyperparameters, significantly enhancing prediction accuracy and robustness. The SHAP method was further applied to interpret model outputs and identify key influencing factors. Results demonstrate that GA-optimized XGBoost achieved the highest predictive performance for both dynamic stability (DS) and indirect tensile strength (ITS), with R² values of 0.9793 and 0.9694, respectively. Curing temperature, RAP content, and curing time were identified as the most influential factors. This study provides an accurate and interpretable ML-based framework for CRMA performance prediction, facilitating optimized mix design for pavement construction and maintenance. Full article

In the context of new-type urbanization and high-quality development, this study aims to construct a multi-objective synergistic land-use mechanism to tackle the “growth-equity-ecology” trilemma in the Chengdu–Chongqing Urban Agglomeration (CCUA). By building an economic–social–ecological benefit evaluation index system and applying TOPSIS with entropy weighting, the coupling coordination degree (CCD) model, and the spatial Durbin model (SDM), we systematically explore the spatiotemporal patterns of land-use benefit synergies and their driving mechanisms. The results reveal the following: (1) From 2015 to 2023, CCUA’s land-use CCD generally improved but showed marked core–periphery polarization. Chongqing’s economic agglomeration worsened regional gaps, while Sichuan’s intra-regional policies boosted internal balance; cross-jurisdictional collaboration eased border disparities but failed to stop overall polarization. (2) Spatial clustering identified hotspots in Chongqing’s main urban and suburban areas and cold spots in eastern Sichuan, reflecting the coexistence of factor agglomeration and cross-border policy synergy. (3) Road network expansion directly hindered CCD, and neighboring ecological protection triggered resource-competition spillovers, emphasizing the key role of cross-regional governance in balancing the “ecology-development” trade-off. This study puts forward spatially differentiated strategies and cross-jurisdictional coordination mechanisms to optimize land-use structures and advance sustainable development in urban agglomerations. Full article

Urban agriculture’s potential for food production and other social benefits is widely documented. However, the diversity of organisational structures and contextual factors that shape and drive the practice leads to a range of productivity levels. Yet, most studies estimate productivity using average production data, which compromises the reliability of the estimates. The objective of the study presented here is to develop a GIS-based spatial analytical framework that takes into account varying levels of productivity for four urban food garden types: Home, Community, Educational, and Commercial. We apply this analytical framework in Bogotá, Colombia, a city at the forefront of policies promoting urban agriculture, where we collected data from a sample of urban food gardens (i.e., produce yield, resource use, and social benefits). To increase the precision and reliability of the estimates, we perform a spatial Multi-Criteria Decision Analysis through several ArcGIS pro 3.1 functions. This allows the identification of suitable areas for each urban agriculture type, based on key spatial and social characteristics (location, proximity to roads and to rivers, private or public land, urban density, and socio-economic demographic conditions). Results suggest that 25% of Bogotá’s surface area (including vacant urban land and roofs) presents potential physical and social conditions for food growing, within which Home Gardens occupy the largest share of suitable land. This shows that land availability is not a key limiting factor to a possible expansion of urban agriculture, particularly at a household level. Resource consumption and educational benefits are also estimated, hence providing a comprehensive picture of the impact of urban food production at a city scale. Full article

As the core area of the Silk Road Economic Belt, Xinjiang still faces problems such as unbalanced development in the process of urban–rural integration, accompanied by the increasingly prominent imbalance between population flow and land resource allocation in county-level towns. Specifically, clarifying the impact of urban–rural integration development on the human–land matching relationship in Xinjiang’s county-level towns is the key to promoting coordinated regional development. This study constructs a spatial matching model and a multinomial logistic regression model to analyze the human–land relationship and the influencing factors of urban–rural integration in 83 county-level towns in Xinjiang from 2010 to 2023. The research results show that (1) from 2010 to 2023, there were significant differences in the spatial matching degree between the total amount and increase in urban population and urban land in Xinjiang’s county-level towns; the number of counties with a relatively high matching level was generally larger in northern Xinjiang than in southern Xinjiang, and the overall spatial matching degree was at a relatively low level. (2) The proportion of counties with sustained population growth and sustained land growth was the highest, reaching 49.40% and 26.51%, respectively. Counties in southern Xinjiang were mainly of the sustained-population-growth type, while counties in northern Xinjiang had more types and were scattered, and were mainly of the land-growth type as a whole. (3) Factors such as the proportion of ethnic minority population, the comparison of industrial output value, and the number of medical beds per capita had a significant impact on the spatial matching level of urban population and land in most types of counties. The types of counties in southern Xinjiang were mainly affected by factors such as the ethnic population structure and medical conditions, while the counties in northern Xinjiang were mostly affected by factors such as the level of industrial coordination and urban spatial expansion. It is suggested to implement differentiated spatial governance and enhance coordination between southern and northern Xinjiang, thereby improving the level of human–land matching and promoting the integrated development of urban and rural areas. Full article

With the acceleration of urbanization in China, the spatiotemporal effects of transportation development have profoundly influenced urban expansion, potentially posing challenges to the sustainable development of urban economic, social, and ecological systems. Existing research has primarily focused on the relationship between transportation systems and urban expansion at the city, urban agglomeration, and regional levels, but studies from a broader spatial scale and spatiotemporal heterogeneity perspective remain relatively scarce. This study examines 364 cities in China, using the proportion of urban construction land area and nighttime light data to characterize urban expansion levels. The geographically weighted regression model is employed to analyze the spatiotemporal heterogeneity of the correlation between transportation development and urban expansion, while the spatial Durbin model is used to explore spatial spillover effects. The results reveal significant spatiotemporal heterogeneity in the relationship between transportation development and urban expansion. From 2010 to 2020, the spatial heterogeneity of the correlation between transportation development and the Percentage of Construction Land Area increased, while the spatial heterogeneity of its correlation with Nighttime Lights decreased. Among the ten transportation development indicators, National Road Density and Density of Street Light showed the most significant correlations with urban expansion. Additionally, some transportation development indicators exhibited notable spatial spillover effects on urban expansion, with Provincial Road Density and Density of Road with Lights having the most prominent impacts. This study provides scientific evidence for planners and policymakers to formulate more precise urban development strategies and promote high-quality, sustainable urban development. Full article

Given the huge contribution of the transportation sector to CO₂ emissions in metropolitan areas, urgent countermeasures are needed to achieve carbon neutrality. In this study of 66 administrative units (cities, counties, and districts) in the Seoul metropolitan area, we applied cluster analysis and a hierarchical regression model to analyze the impact of the 7D factors of Transit-Oriented Development (TOD) on CO₂ emissions from road transportation. The effects of TOD factors were found to vary in diverse contexts. A higher concentration of employment intensified regional travel demand, thereby increasing emissions—a phenomenon referred to as the Paradox of Concentration. In contrast, the expansion of urban rail and bicycle infrastructure facilitated modal shift toward sustainable transport but simultaneously stimulated commercial and logistics activities, leading to elevated overall emissions. Thus, a ‘two-faced infrastructure’ pattern is evident in the Seoul metropolitan area. Conversely, strengthened local self-containment by destination accessibility promoted short-distance travel, curbing emissions. These outcomes empirically exhibit that the low-carbon effect of TOD is contingent, implying that urban structure and policy context are key factors in determining emission pathways. The impacts of the TOD 7D factors are discussed in terms of emission effects, and differentiated policy directions reflecting inter-city heterogeneity are suggested. In particular, the results of our analysis emphasize the need for comprehensive TOD strategies that combine transportation infrastructure, demand management, local self-containment, and zero-emission logistics systems, beyond simple compact development strategies. The policy implications described here are applicable in other countries experiencing rapid urbanization. Full article

With the continuous expansion of rural road construction and increasing management demands, traditional rural road inspection and maintenance models are becoming insufficient to meet current needs. The analysis of inspection results and the development of maintenance plans are often delayed. To address these challenges, this paper proposes a rural road distress sample recognition and annotation method based on machine vision techniques, and establishes a corresponding disease target identification sample database. The method is trained and validated using the U-Net algorithm, achieving an accuracy of 94.95%. Additionally, a lightweight detection system is developed to facilitate rural road surface disease target detection and automatic recognition. The self-developed automatic recognition system significantly enhances the accuracy and efficiency of pavement disease recognition. Furthermore, a management platform has been implemented to enable the dynamic management of rural road disease data and maintenance operations. Full article

Ensuring equitable access to basic education is a core issue for promoting balanced regional development and sustainable educational outcomes. As a vast and sparsely populated region with relatively slow development, the Qinghai–Tibet Plateau faces particular challenges in ensuring educational accessibility and equity. Using a 100 m × 100 m travel time cost raster constructed from OSM road networks and the cost-distance method, together with local spatial autocorrelation, Lorenz curve, and Gini coefficients, as well as the Geodetector method, this study examines the spatial equity and factors influencing the accessibility of primary and secondary schools across 2798 townships at three time points (2016, 2020, and 2024) under three scenarios: Scenario 1 (nearby schooling), Scenario 2 (schooling within the prefecture-level city), and Scenario 3 (schooling within the county). The results show that: (1) Overall accessibility improved from 2016 to 2024, with primary schools being more accessible than secondary schools. Western townships, although initially disadvantaged, experienced the most notable gains. However, accessibility declined markedly when administrative-boundary constraints were imposed, with the greatest losses observed in ultra-high-altitude remote areas such as Ngari and Nagqu. (2) Spatial equity also improved, but when administrative boundaries were imposed, population-weighted inequities became even more pronounced than disparities in accessibility itself. Equity declined most sharply under county-level constraints, with pronounced impacts on both primary and secondary schooling. (3) Spatial variations in accessibility were jointly driven by multiple factors. In Scenario 1, road network density and population density had the strongest explanatory power. Under administrative boundary constraints, however, county type and ethnic autonomy became increasingly influential. In conclusion, in ultra-high-altitude areas where natural conditions remain difficult to overcome, improving educational equity depends less on transport expansion or facility provision and more on relaxing county-level boundary restrictions that constrain access to services. These findings may provide useful evidence to inform targeted policy interventions and resource allocation strategies aimed at promoting equitable access to basic education in underdeveloped and high-altitude regions. Full article

In the São Brás de Alportel municipality, water scarcity poses a significant constraint on agricultural activities. This study utilises Remote Sensing (RS) and Geographical Information Systems (GISs) to identify existing irrigated areas, delineate catchment basins, and select the most suitable sites for the installation of new surface water reservoirs. First, the principal territorial components were characterised, including physical elements (climate, geology, soils, and hydrography) and anthropogenic infrastructure (road network and high-voltage power lines). Summer Sentinel-2 satellite imagery was then analysed to calculate the Normalised Difference Vegetation Index (NDVI), enabling the identification and classification of irrigated agricultural parcels. Flow directions and accumulations derived from Digital Elevation Models (DEMs) facilitated the characterisation of 38 micro-catchments and the extraction of 758 km of the drainage network. The siting criteria required a minimum setback of 100 m from roads and high-voltage lines, excluded farmland currently in use, and favoured mountainous areas with low permeability. Only 18.65% (2854 ha) of the municipality is agricultural land, of which just 4% (112 ha) currently benefits from irrigation. The NDVI-based classification achieved a Kappa coefficient of 0.88, indicating high reliability. Three sites demonstrated adequate storage capacity, with embankments measuring 8 m, 10 m, and 12 m in height. At one of these sites, two reservoirs arranged in a cascade were selected as an alternative to a single structure exceeding 12 m in height, thereby reducing environmental and landscape impact. The reservoirs fill between October and November in an average rainfall year and between October and January in a dry year, maintaining a positive annual water balance and allowing downstream plots to be irrigated by gravity. The methodology proved to be objective, replicable, and essential for the sustainable expansion of irrigation within the municipality. Full article