Analyzing the relationship between human thermal environment and human flow toward a walkable city

1. Introduction

‘Walkable city’ is a concept for urban design that prioritizes pedestrians and is becoming popular in Japan. This walkability is influenced by the characteristics of the built environment, microclimate, and so on. Because occupant comfort is an influential factor for outdoor usage despite warming climates during summer, in the present study, we focus on the relationship between the human thermal environment and human flow to improve occupant experience.  

2. Methodology

To analyze this relationship, we conducted field measurements using human participants (10 participants for every season) in different locations in real urban streets throughout the year. Human flow was simultaneously obtained using a mobile location data. To quantify the human thermal environment, the human thermal load was calculated based on measurements. Solar and infrared radiation, air temperature and relative humidity, wind speed and direction, and participants’ skin temperature and activity level were recorded at 1-min intervals. Perceptions such as thermal sensation and comfort were also recorded at 5-min intervals. The human thermal load is considered to be an indicator of a human’s physical state. This pilot study was conducted in Toyohashi, Japan, in cooperation with the city government.

3. Results and summary

We successfully quantified both the human thermal environment and the human flow. Generally, there is no clear relationship between them in the scatter plot because many factors other than thermal comfort affect travel routes. However, the area that needs to be thermally improved becomes clear, for example, a street with high pedestrian traffic and a poor thermal environment. Additional analyses depending on the season and time period were also conducted; thus, we can obtain a future direction for a walkable city in Toyohashi.