Search Results (124)

Satellite-derived land surface temperature (LST) is widely used for urban heat assessment, but its correspondence with pedestrian exposure is uncertain. We compared ECOSTRESS-derived LST with ENVI-met-simulated Universal Thermal Climate Index (UTCI), treated as a model-based heat-exposure indicator, across 24 Seoul Local Climate Zone plots. One ECOSTRESS scene acquired five days before the ENVI-met simulation served as the primary near-date, hour-matched comparison under comparable meteorological conditions rather than a simultaneous field observation; four scenes from 2021–2025 were treated as separate cross-date sensitivity observations. A source audit retained 118 of 120 plot × scene records. The primary association was weak (r = 0.199, p = 0.351, R² = 0.040, n = 24). The unadjusted pooled benchmark explained 6.1% of UTCI variance, whereas the scene-adjusted LST slope was 0.060 °C UTCI per °C LST (plot-cluster-robust 95% CI −0.075 to 0.195; p = 0.371). Because only two plots represented each LCZ, leave-one-plot-out and stratified bootstrap results were interpreted only as discrete perturbation diagnostics. ECOSTRESS LST therefore did not demonstrate stable proxy performance for simulated pedestrian heat exposure under this design. CPE is retained as a conceptual organizing heuristic, not a validated classifier or transferable LCZ ranking. Full article

Autonomous micromobility vehicles (AMVs) need local planning that balances task progress, safety, and pedestrian interaction quality in pedestrian-rich shared spaces. Evaluating such planners is difficult because studies vary scenarios, seeds, metrics, outputs, and aggregation rules, while single-score leaderboards hide which behaviors produce a ranking. This paper proposes a repeatable, auditable, multi-objective benchmark protocol for AMV local planning. Before comparison, it fixes the scenario set, repeated seeds, measured metrics, stored outputs, planner-interface records, and aggregation procedure. We demonstrate it with a frozen robot_sf_ll7 campaign: 47 shared-space scenarios, three evaluation seeds, and 141 scenario-seed episodes per planner in one differential-drive AMV configuration. The stress test surfaces a descriptive safety–performance separation: a Proximal Policy Optimization (PPO)-family profile reaches higher observed mean task success than a classical reciprocal-avoidance baseline, while that baseline keeps lower collision exposure. Absolute success stays low for both, with most scenarios unsolved by either. Because this learned policy was trained on a superset of the evaluation scenarios, its higher success reflects behavior on the benchmark set, not held-out generalization—an overlap the protocol records per planner rather than hiding in one score. The finding is bounded to these configured pipelines, not a universal planner-family ranking. The contribution is an auditable comparison framework tracing results from the scenario matrix and fixed seeds to episode records, aggregate reports, and manifests. Full article

Construction dust is a major contributor to urban inhalable particulate matter (PM₁₀) pollution, posing severe respiratory and cardiovascular health risks to construction workers and nearby residents, severely undermining urban environmental sustainability. Construction fences are widely adopted as a primary dust mitigation measure, yet their underlying dispersion mechanisms and comprehensive impacts on vertical air quality remain poorly understood due to the limitations of traditional field monitoring and empirical models, creating critical barriers to site-level pollution control and long-term urban sustainability. In this study, a reliable computational fluid dynamics (CFD) method was developed to investigate the spatial distribution of construction dust and quantify the dust suppression performance of fences with heights ranging from 0 to 3 m. Three mainstream k-ε turbulence models (Standard, RNG, and Realizable) were evaluated using on-site measurement data, and the RNG k-ε model was found to provide the best agreement with field observations, with statistical metrics of q = 1, FB = 0.052, and NMSE = 0.028. The results show that construction fences effectively reduce dust dispersion into the surrounding environment, particularly in the pedestrian breathing zone (z < 1.5 m). Increasing the fence height from 1.5 m to 3 m improves the breathing-zone dust reduction rate from 39% to 55%, with the most significant mitigation effect observed within 50 m downwind of the fence. However, a critical dual effect was identified: while fences suppress near-ground pollution, they induce strong upward airflow and turbulence, leading to elevated dust concentrations in the upper part of the near-ground region (z = 1.5–9 m), a phenomenon absent in the no-fence scenario. These findings provide practical implications for urban construction site management, suggesting that fence height and configuration should be carefully designed not only to reduce pedestrian-level exposure but also to avoid unintended pollutant accumulation aloft, thereby improving overall air quality control strategies and delivering balanced, long-term environmental sustainability at construction sites. Full article

Urban heat and walkability are often assessed separately, although pedestrians experience street connectivity, topography, vegetation, and thermal exposure simultaneously. This study develops a reproducible open-data workflow to examine the spatial relationship between walkability potential and surface thermal pressure in Loja, Ecuador, an intermediate Andean city shaped by valley morphology, steep slopes, uneven urban expansion, and heterogeneous green-space distribution. The analysis combines Landsat-derived land surface temperature, OpenStreetMap urban-form indicators, DEM-derived slope, composite spatial indicators, and spatial autocorrelation across 100 m, 250 m, and 500 m grids. The results show that walkability potential, observed LST-based heat intensity, and walkability–heat balance is spatially structured rather than randomly distributed. At the 250 m scale, heat-intensity clusters were spatially selective, indicating that surface thermal pressure is concentrated in specific parts of the retained analytical grid rather than uniformly distributed across the city. The 250 m grid provided the most interpretable balance between local detail and spatial stability for this case study, while the 100 m and 500 m grids revealed the sensitivity of the results to spatial aggregation. The study does not measure physiological thermal comfort or pedestrian heat stress. Instead, it offers an exploratory diagnostic framework for identifying where pedestrian-supportive urban form and surface thermal pressure overlap or diverge. This approach can help data-constrained intermediate cities prioritize areas for field verification, shade assessment, green-infrastructure planning, and more detailed pedestrian-level thermal studies. Full article

Urban heat island effects increasingly challenge pedestrian mobility by intensifying thermal stress and reducing the attractiveness of walking during hot periods. However, most pedestrian routing systems still prioritize distance or travel time, while environmental conditions such as heat exposure and shade are rarely incorporated into operational route generation. Existing comfort-aware approaches often rely on static maps, simulated microclimatic indicators, or descriptive greenery measures, limiting their direct integration into user-configurable pedestrian navigation. This study develops a thermal comfort-aware pedestrian routing framework that integrates heterogenic data sources including observed land surface temperature, pedestrian-perspective tree-canopy coverage, and network distance into a unified multi-criteria pathfinding model. The workflow proceeds in four steps: first, airborne thermal imagery is processed to derive a high-resolution land surface temperature layer; second, Google Street View images are sampled at street-segment locations and segmented using SegFormer to extract visible tree-canopy coverage; third, both environmental indicators are aggregated to a cleaned pedestrian network; and fourth, normalized distance, temperature, and canopy attributes are combined through a user-adjustable edge-cost formulation and solved using Dijkstra’s algorithm. The framework is implemented as an operational web-based routing tool for the historic center of Clermont-Ferrand, France. The routable graph includes 551 nodes and 796 edges, with 600 segments carrying GSV-derived canopy information and 623 segments carrying airborne-derived LST values. Across the network, we observed LST ranges from 19.5 °C to 39.1 °C, while canopy coverage ranged from 0 to 70.6%. For a representative origin–destination pair, the coolest route reduces average LST by nearly 5 °C and almost triples canopy coverage compared with the shortest path, although at the cost of a 72% longer distance. These results demonstrate that the framework can generate interpretable comfort–efficiency trade-offs and support user-comfort pathfinding as an operational approach for heat-resilient pedestrian navigation. Full article

The concrete industry intends to include HPC for structural applications in Southern Europe and, therefore, Greece is a region characterized by stricter and problem-oriented sizing and reinforcement limitations due to its strong seismicity. For this purpose, the effect of using of high performance concrete (HPC) on the dimensioning of conventional reinforced concrete (RC) and prestressed concrete (PC) structures is investigated by designing two ten-story office buildings and typical PC pedestrian, railway, and road bridges, while conforming to all the relevant provisions of the Eurocodes. The designs involve practical construction forms obeying geometric limitations, while satisfying all serviceability and ultimate limit states for conventional and accidental earthquake loads. Conventional strength-class concrete, namely C30 for buildings and C35 for PC bridges, and HPC concrete classes C60 to C120 are considered. Based on the parametric designs, it is concluded that using HPC leads to a reduction in concrete volume of between 30% and 50% compared to conventional concrete use. This reduction, however, depends strongly on the design-controlling criteria, building occupancy, and bridge type and span, which may lead to smaller material savings, particularly where serviceability criteria govern. The analysis is extended in order to also investigate the increase in the design service life of these structural forms under marine chloride exposure conditions, using C90 and conventional concretes. It is shown that, in addition to the material reductions above, the use of HPC also results in a significant increase in the design service life of the structures considered. Full article

Walkability measurement has expanded from a small set of generic neighbourhood-level proxies into a heterogeneous field of indices, scored audits, perceived-environment scales, route-based instruments, and context-specific assessment instruments. This expansion has improved the sensitivity of walkability research, but it has also made it increasingly difficult to judge which instruments are appropriate for different users, walking purposes, and urban or environmental contexts. This review addresses this problem by comparing operational walkability instruments through an adapted walking-needs framework derived from the Expanded Hierarchy of Walking Needs (HoWN). Publications from 1990 to 2025 were identified through a structured search and screening workflow covering general walkability measurement, population-sensitive instruments, purpose-specific instruments, climate- and exposure-sensitive instruments, and urban-form-specific instruments. After eligibility assessment and consolidation, 46 walkability instruments were retained for comparative analysis. For this review, the framework is adapted from a behavioural hierarchy into an instrument-level comparative structure, with feasibility re-specified as basic environmental passability. The instruments are then compared across five tiers: feasibility, accessibility, safety, comfort, and pleasurability. The review shows that walkability measurement remains strongly concentrated in lower-order and functionally measurable dimensions, especially pedestrian infrastructure, destination access, connectivity, and traffic safety. By contrast, comfort, pleasurability, environmental exposure, personal security, and user-specific constraints are less consistently formalised and often appear only in specialised instruments. Population-, purpose-, climate-, and urban-form-sensitive instruments do not merely add indicators; they alter which walking needs become foundational in specific assessment scenarios. This review contributes a fit-for-purpose comparative logic for walkability measurement. It shows how a shared walking-needs framework can be used to diagnose coverage imbalance, identify scenario-specific threshold conditions, and guide the selection, adaptation, and transfer of instruments across different users, walking purposes, environmental exposures, and urban forms. Full article

Background: Urban road-traffic fatalities are a public health burden and a governance challenge because protection is uneven across urban space and time. Methods: We analyzed 702,540 administrative road-incident records from Medellín, Colombia (2008–2025), identified 2762 fatal cases, standardized incident categories, and harmonized time and coordinate fields. Spatial analyses were based on 2507 geocoded fatalities. We combined descriptive profiling, chi-square tests, logistic regression comparing pedestrian-strike and collision fatalities, sensitivity analyses using grouped time periods and a pandemic-period indicator, and spatial autocorrelation measures using Moran’s I and Getis–Ord $G_i^{*}$. Results: Incident type composition did not differ significantly between daytime and nighttime, but it varied across districts (comunas). Each later hour was associated with slightly higher odds that a fatality would be classified as a pedestrian strike rather than a collision (OR = 1.033), and fatalities in the urban core had nearly threefold higher odds of being classified as pedestrian strikes (OR = 2.953). Sensitivity analyses did not materially alter these associations. Spatial statistics showed strong clustering among the dominant fatality classes and identified 129 significant hotspot cells. Conclusions: Fatal road-traffic harm in Medellín is spatially concentrated and varies by incident mechanism, with pedestrian fatalities disproportionately concentrated in central areas of intense pedestrian–vehicle interaction. These findings show that transparent surveillance analytics can inform governance prioritization while also underscoring the need to improve data completeness, incorporate exposure measures, and interpret pandemic-period patterns with caution. Full article

In the context of subtropical cities, the slow-moving environment of HOD (Hospital-Oriented Development) faces the dual challenges of spatial fragmentation and an extreme hot and humid climate, which also restricts the outdoor space’s thermal environment performance. Taking the Macau Light Rapid Transit (LRT) Union Hospital Station as an example, this study constructs a “topology-climate” dual quantitative assessment framework that integrates space syntax and parametric universal thermal climate index (UTCI) simulation. In response to the current problems of mixed pedestrian and vehicular traffic and high-intensity heat radiation, a comprehensive intervention strategy combining three-dimensional stitching and spatial optimization is proposed. The results show that: (1) The implantation of three-dimensional corridors improved the spatial integration of the core area of the site by 67.0%, significantly optimizing network connectivity. (2) During the extreme high-temperature period of daytime (9:00–18:00) in summer and autumn, the intervention strategy precisely opened up a continuous low-heat-stress linear shade zone through the synergistic mechanism of building projection shadows, physical shading of connecting corridors, (landscape shading effect, original evaporation removed). (3) The study confirms that landscape-coupled shading layout is the most effective method, reducing potential pedestrian heat exposure across the entire area, while the three-dimensional connecting corridors precisely control the thermal environment of core walkways. Together, these two elements construct a “topology-climate” optimization framework, achieving a synergistic improvement in spatial accessibility and simulated thermal comfort performance under standard meteorological input and quantitatively verifying the optimization effectiveness of the tiered intervention scheme. This study provides a data-driven decision-making basis for optimizing potential walking thermal conditions for vulnerable groups and reshaping the space’s potential to improve microclimate via shading design of medical hub areas and also provides a scientific paradigm for TOD microclimate planning focused on shading-based thermal environment optimization. Full article

In coastal residential areas, the combined effects of high temperature, high humidity, and weak wind conditions during summer intensify outdoor heat exposure and reduce pedestrian thermal comfort. To investigate the influence mechanisms of tree height and spatial layout on pedestrian-level thermal comfort, this study selected a typical residential community in Chengyang District, Qingdao, as the research site. Based on field meteorological observations, an ENVI-met model was established and validated. Using the existing composite greening scenario as the baseline, three tree layout types (row, cluster, and free layouts) and four height scenarios (4 m, 6 m, 8 m, and 10 m) were configured to quantitatively compare variations in physiological equivalent temperature (PET) under different planting schemes. The results indicate that tree configuration significantly affects summer thermal comfort. Its regulatory mechanism is governed not only by air temperature reduction but also by shortwave radiation interception, longwave radiation accumulation, and shading continuity. Although low-to-medium height trees can reduce local air temperature through transpiration, their limited canopy height and shading continuity restrict their ability to effectively attenuate direct shortwave radiation at pedestrian level, and in some cases may even increase mean radiant temperature (Tmrt) and PET. In contrast, 10 m tall trees arranged in row and cluster layouts can form continuous shaded cores, with the 10 m cluster layout demonstrating the best overall performance by significantly reducing Tmrt and PET. The free layout, characterized by dispersed canopies and fragmented shading, provides relatively limited thermal comfort improvement. The findings suggest that residential greening optimization should strengthen the coordination between tree height, canopy structure, and activity spaces. Tall trees should be prioritized in children’s play areas, elderly resting areas, residential entrances, main pedestrian pathways, and west-facing sun-exposed zones, while integrating building shadows and road orientation to create a continuous yet not overly enclosed shading network, thereby enhancing summer thermal adaptability in residential areas. Full article

Public spaces in cold-region historic districts often contain a mismatch between spatial accessibility and winter environmental usability. Highly accessible streets may be exposed to strong winter winds, whereas sheltered spaces may remain underused because of weak network connectivity. Taking the Xinmin Street historic district in Changchun, China, as a case study, this study develops a coupled analytical framework that integrates space syntax, ENVI-met microclimate simulation, and GIS-based overlay analysis to identify winter public-space potential under heritage conservation constraints. Visual integration derived from Depthmap was used to represent configurational accessibility, while pedestrian-level wind speed at 1.5 m was used to characterize winter wind exposure under a representative clear winter-day scenario. The results show that high-integration areas are concentrated along the main north–south street, but several of these segments coincide with wind corridors and therefore show limited winter usability. Conversely, low-wind areas are mainly located on the leeward sides of buildings and within relatively enclosed spaces, although some lack sufficient pedestrian connectivity. Low-intervention optimization, including link completion, entrance adjustment, permeability enhancement, and winter-priority route organization, increased the average integration value of low-wind spaces from 7.41 to 8.82. The framework helps planners and conservation authorities identify sheltered but under-connected spaces and supports heritage-sensitive renewal strategies for improving winter public-space usability in cold-region historic districts. Full article

Urban green spaces play a critical role in mitigating heat stress and enhancing urban livability, in line with the objectives and expectations of the United Nations Sustainable Development Goals 10 (Reduced Inequalities) and 11 (Sustainable Cities and Communities). This study employs Physarealm (Grasshopper), a lightweight agent-based simulation (ABS) model, to dynamically simulate pedestrian behaviors for different mobility groups. Together with Space Syntax, the results—time-extended movement and interaction patterns—are conceptualized as a relational configuration of green space provision (supply), pedestrian activity intensity (demand), and thermal exposure (environmental resistance). Three contrasting urban areas in northern Italy (Lambrate, Bolognina, and Ispra) are selected as case studies. The results demonstrate that urban inequality cannot be sufficiently explained by the inadequacy of single components, but emerges from imbalanced relational configurations of supply, demand, and environmental resistance. In May, 100% and 95% of traversed cells in Lambrate and Bolognina fall within the high-heat-stress range (>32 °C), compared with 59% in Ispra. Correspondingly, average green provision within the 5 min walking range is 5.4% in Lambrate, 7.2% in Bolognina, and 37% in Ispra. By uncovering relational mismatch patterns that are often overlooked in conventional urban analyses, this study enables a multi-dimensional diagnosis of imbalances. By positioning ABS as a front-end process generator and Space Syntax as a structural interpretation step, it demonstrates how dynamic behavioral processes can be reorganized into network-scale diagnostic representations. The study supports a climate-sensitive and human-centered diagnosis of walkability and green space accessibility, while contributing a transferable analytical approach for identifying relational inequality patterns within open urban data science contexts. Full article

Pedestrian safety at urban intersections requires risk-aware mechanisms that extend beyond binary collision detection toward comparative prioritization among multiple agents. This study introduces the Intelligent Pedestrian Model (IPM), a reference-normalized scalar framework that represents pedestrian risk as a function of trajectory, contextual, infrastructural, and behavioral factors, decomposed into Exposure and Severity components. Building on IPM, the Safety-Prioritized Trajectory Model (SPTM) operationalizes the Exposure component using an observation-only, leakage-free kinematic proxy embedded into a cost-aware negative log-likelihood objective. Evaluation on the ETH/UCY benchmark under a strictly inductive protocol shows that moderate prioritization (β ≈ 1.0) improves best-of-K multimodal performance (ALL FDE@K: 0.979 → 0.970 m) while maintaining mean displacement accuracy within seed-level variability. The results indicate that Exposure-based weighting does not act as a global accuracy enhancer but redistributes predictive capacity toward safety-relevant motion regimes. Validation currently covers two ETH/UCY folds under a controlled inductive protocol, while broader cross-fold evaluation remains for future work. Full article

Background: Cannabis legalization has raised concerns regarding its potential influence on injury patterns, particularly among children. However, evidence on pediatric trauma remains limited. Objective: To examine trends in pediatric trauma incidence, injury mechanisms, healthcare utilization, and socioeconomic characteristics before and after recreational cannabis legalization in Nevada. Methods: A retrospective repeated cross-sectional study of trauma registry data was conducted using pediatric trauma activations recorded between 2013 and 2023. Incidence rates per 100,000 population were calculated using census data. Pre-legalization (2013–2016) and post-legalization (2017–2023) periods were compared using incidence rate ratios (IRRs) and bivariate tests. Socioeconomic status was assessed using the Distressed Communities Index (DCI). Results: Among 1772 pediatric trauma activations, overall incidence remained stable (21.6 vs. 21.4 per 100,000; IRR = 0.99, 95% CI: 0.90–1.09). Post-legalization, motor vehicle collision-related injuries increased (49.3% vs. 41.3%, p = 0.002), while pedestrian injuries declined (25.5% vs. 32.4%). ICU admissions decreased (19.5% vs. 27.3%, p < 0.001), although ICU length of stay increased (5.9 vs. 4.0 days, p = 0.005). A higher proportion of patients originated from less distressed communities post-legalization (p = 0.021), alongside shifts in insurance coverage (p < 0.001). Conclusions: Pediatric trauma incidence remained stable following cannabis legalization in Nevada; however, shifts in injury mechanisms, healthcare utilization, and socioeconomic patterns were observed. Because cannabis legalization was assessed at the population level and individual cannabis exposure was not directly measured, findings should be interpreted as temporal associations rather than causal effects. These findings highlight the need for ongoing surveillance and targeted, equity-focused injury prevention strategies. Full article

High-density urban plazas hosting multi-session public events often experience pulsed inflows, prolonged crowd retention, and localized bottleneck congestion, creating crowd-safety risks that cannot be fully captured by static capacity or total evacuation time alone. This study develops an agent-based simulation framework to evaluate ultra-high-density exposure and evacuation dynamics in Guangzhou Huacheng Plaza during the International Light Festival. The model was constructed in AnyLogic using site-layout data, event organization records, official attendance information, historical event timelines, and publicly available video observations. Two scenarios were examined: normal dynamic entry–exit operation under different inter-performance intervals, and overload-triggered evacuation under alternative spatial management strategies. Model calibration and event-process validation were conducted by comparing simulated congestion hotspots, key event timing, delayed dispersal patterns, and evacuation-duration ranges with historical observations and documented event records. The results show that extending the inter-performance interval from 90 min to 120 min reduced the overload duration from 75 min to 5 min and decreased cumulative ultra-high-density exposure from 25.62 to 13.93. Under overload evacuation, zonal guidance mainly improved early-stage crowd redistribution, whereas increased exit capacity produced a stronger reduction in total evacuation time and sustained congestion. Total evacuation time decreased from 185 min in the baseline condition to 160 min under the combined strategy, while effective discharge capacity increased from 231.12 to 338.28 pedestrians/min. These findings indicate that crowd safety in open urban plazas depends not only on total attendance, but also on event pacing, bottleneck recovery time, and effective discharge capacity. The proposed exposure-oriented framework provides a quantitative basis for evaluating crowd accumulation and evacuation strategies in high-density open public spaces. Full article