1. Project Overview
This project aimed to create a safer andmore comfortable urban environment during periods of extreme heat by developinga heatstroke hazard map. The initiative seeks to support Shibuya residents andvisitors in making informed decisions about outdoor activities during hotweather while improving their ability to anticipate and avoid heat-relatedrisks.
2. Background and Challenges
In recent years, extreme urban heat hasbecome an increasingly significant challenge. Rising temperatures havecontributed to a higher risk of heat-related illnesses, reduced economicactivity due to decreased pedestrian circulation in commercial areas, and thecancellation of outdoor activities such as sports events, community gatherings,walking, and children's outdoor play.
Furthermore, actual on-site temperaturescan differ by more than 10°C from temperatures indicated by conventionalweather data. This highlights the need for an environment in which individualscan accurately understand the heat conditions of their immediate surroundingsand make informed decisions while outdoors.
3. Project Activities
This initiative was implemented as a memberproject of Shibuya Innovation Institute (SII). Project members included DAIKIN INDUSTRIES, LTD., a corporate member of SII; Shibuya Future Design; beacappInc., a startup specializing in the visualization of people and objectmovements using beacons and various sensors; and NIKKEN SEKKEI LTD, whichparticipated as a collaborative partner. The project was conducted fromNovember 2025 through March 2026.
As an initial pilot effort, the projectfocused on the Dogenzaka area around Shibuya Station. A highly detailedheatstroke hazard map was developed to objectively visualize where and whenpeople are exposed to heat-related risks. Using outdoor air temperature datacollected from rooftop air-conditioning units, the project created a Wet BulbGlobe Temperature (WBGT) map, a key indicator for assessing heat stress. Themap reconstructed environmental conditions at a fine spatial resolution of5-meter mesh grids, significantly exceeding the granularity of conventionalmeteorological and public-sector datasets.
The hazard mapis currently available on the Shibuya Future Design website.
【渋谷の熱を可視化】渋谷における高精度の熱中症ハザードマップを公開 - 一般社団法人渋谷未来デザイン
In addition to rooftop temperature data,the project integrated multiple datasets, including land surface temperature,shadow and sunlight information derived from a 3D city model, and pedestrianflow data. By combining these data sources, the project was able to representheat exposure conditions more closely aligned with what pedestrians actuallyexperience on the ground.
For the heat environment analysis, outdoortemperature data collected during the three-month period from July throughSeptember 2025 were utilized. The hazard map itself was based primarily onAugust data, the period when heatstroke risk is at its highest. The resultingmap can be used not only to identify areas with particularly intense heat butalso to evaluate pedestrian movement patterns. This information can supportplanning decisions such as where to install cooling spots and how to designwalking routes that minimize heat exposure.
4. Outcomes and Insights
The project successfully visualizeddetailed distributions of heat-related risk within the Dogenzaka 1-chome areausing a 1-meter-resolution WBGT map, capturing variations that cannot beidentified through standard meteorological observations alone. The analysisquantitatively and visually demonstrated that heatstroke risk can varysignificantly even within the same intersection or street, depending on factorssuch as sun exposure, shade, slopes, and building shadows.
Another important finding was thaturban-scale heat conditions can be assessed without installing large numbers ofnew sensors. By utilizing temperature data collected from air-conditioningunits already deployed throughout the city, the project demonstrated thepotential for cost-effective monitoring of urban thermal environments.Furthermore, combining pedestrian flow data from startup partners witharchitectural and urban analysis techniques, such as 3D shadow simulations,enabled the development of outputs directly applicable to policy planning andservice design, including cooling spot placement and pedestrian routeoptimization.
The integration of diverse datasets,including rooftop air-conditioning data, land surface temperatures, 3D urbanshadow information, and pedestrian flow data, also enabled analysis thatconsiders both heat distribution and human movement patterns. Rather thansimply identifying hot areas, the project demonstrated how data-drivenapproaches can support practical interventions, such as locating cooling spotsnear areas with high pedestrian traffic and recommending shaded routes duringpeak travel periods.
The project further suggests that combiningmultiple data sources to create hazard maps has applications beyond heatmitigation and could help address a wide range of urban challenges. Followingthe publication of the project results, the team received inquiries andconsultation requests from municipalities interested in strengthening their ownheat resilience measures. These responses indicate growing interest inutilizing environmental data derived from existing infrastructure, such asair-conditioning systems, as a form of urban data that contributes to solvingsocial challenges. Overall, the findings demonstrate that urban heat mitigationcan go beyond simply providing temperature information and serve as afoundation for supporting behavioral change and evidence-based urbandecision-making through data integration and visualization.
5. Future Outlook
Building on the insights gained from thispilot area, the project team plans to expand the approach to other areas withinShibuya City and eventually to municipalities across Japan. The team alsointends to incorporate additional information, such as green infrastructure,street trees, underground passageways, and underground shopping areas, todevelop the platform into a tool for designing safe and comfortable mobilityroutes and heat-resilient urban environments.
In addition, the team aims to collaboratewith map service providers, walking and mobility application developers,commercial facilities, and event organizers so that the hazard map becomesseamlessly integrated into everyday travel and consumer activities rather thanserving solely as an information resource.
Throughout the project, valuable supportand feedback were received from local businesses and residents who participatedin the demonstration activities. By building on this collaborative foundation,the project team will continue working toward a citywide approach to heatmitigation through the sharing and utilization of environmental data at anurban scale. Ultimately, the goal is to establish a new model for heatresilience originating from Shibuya and to create an urban environment wherepeople can safely and comfortably remain active even during periods of extremeheat.
This article was translated into English using AI.
