The research, titled "Understanding How Extreme Heat Impacts Human Activity-Mobility and Time Use Patterns," led by Professor Ram M. Pendyala of ASU, explores how rising temperatures are reshaping human behavior in urban settings. The team analyzed data from the American Time Use Survey, alongside weather records from NOAA, focusing on 11 major U.S. cities. Their findings reveal that during extremely hot days, people tend to stay indoors, limit outdoor activities, and avoid unnecessary trips.

Shifting Transportation Habits

One of the study's most striking findings is the shift in transportation habits during heat waves. People are much more likely to rely on cars, with walking, biking, and public transit usage dropping dramatically. Public transit use falls by nearly 50% on very hot days as commuters opt for air-conditioned cars instead, posing challenges for cities striving to encourage sustainable travel options.

Moreover, the research underscores that certain groups are more vulnerable to these changes. Low-income individuals and those without access to cars, who typically depend on walking or public transit, are disproportionately exposed to dangerous temperatures. These groups are also less able to adjust their work schedules, forcing them to travel even in severe heat.

The study also highlighted that older adults find it particularly difficult to adapt their routines during heat waves, leading to potential risks of social isolation.

Addressing Inequities in Extreme Heat

Professor Pendyala emphasized that extreme heat worsens existing disparities in mobility and participation in activities. He called for policies specifically designed to protect vulnerable populations from the escalating impacts of climate change. As cities around the world face increasingly frequent heat waves, this research underscores the urgent need for adaptive strategies to ensure fair access to transportation and safeguard residents' quality of life during periods of extreme heat.