Analyzing transit-based heat exposure and behaviors to enhance urban climate adaptation and mitigation strategies in the southwest USA

Public transportation systems represent an intersecting point between urban climate change adaptation and mitigation strategies. Increasing the use of public transit systems can help cities meet a wide range of sustainability and health goals including reductions in greenhouse gas emissions. Simultaneously, public transit use typically necessitates exposure to outdoor weather. In extreme climates, uncomfortable or dangerous weather conditions may suppress public transportation system without sufficient infrastructure to moderate exposure.

This paper will present results from a suite of ongoing research projects in the hot desert city of Phoenix, Arizona, that aim to understand and improve public transit riders’ experiences and resilience to heat. Researchers have been using a wide range of methodologies to assess environments, conditions, and the behaviors and perceptions of public transit riders, including observations, surveys, ridership data, in situ and transect-based micro meteorological measurements, and handheld and satellite-based thermal imagery. Results support the importance of shade provision for public transportation use in the summer, including the availability of nearby shade at bus stops from surrounding trees and buildings. Survey and observational data revealed key behaviors and perceptions that should influence transit stop design strategies: stops with more design and natural features are perceived as more thermally comfortable by public transit users; riders identified infrastructure elements and coping behaviors that make them feel cooler. Findings also showed that current infrastructure standards and material choices for bus stops can increase the air temperature at the stop, and, thus, contribute to heat stress accumulation.

As the City of Phoenix intends to make large investments in public transportation infrastructure in the coming decades, continued attention to the experiences and preferences of transit riders—especially during the summer months—will improve the likelihood that the region can meet or exceed its public transportation and sustainability goals.