Investigation of heat stress on urban roadways for commuting children and mitigation strategies from the perspective of urban design

Rapid urbanization and global warming have triggered frequent heat waves that pose a threat to human survival, with a marked increase in childhood morbidity. While previous studies have explored the thermal environment of children's public activity places, only limited studies have focused on the commute of school children, which is a regular activity causing potential risk of heat stress. From an urban design perspective, this study systematically investigated the influence of building shade, road orientation and tree species on the thermal environment of commuting roads. The simulation results indicated that, regarding the reduction of road heat stress, the building shade has a greater impact that can reduce the mean radiant temperature by 3.22 °C to 21.25 °C, compared to the effect of tree shade (0.02–6.04 °C). Furthermore, planting street trees in a flexible manner to add building shade areas can enhance thermal safety. For road orientations, increasing shade areas of north-south road generates more benefits in heat stress mitigation (in the northern hemisphere). Finally, from the perspective of urban design/management and school children, a set of heat stress mitigation strategies are proposed to promote the thermal safety of school children and stimulate the development of a sustainable and healthy urban environment.