How heat waves are changing urban routines

Kaleigh Harrison

A study conducted by researchers at Arizona State University, the University of Washington and the University of Texas at Austin has revealed the significant impact of extreme heat on human activity patterns and mobility decisions in major US cities. As urban centers around the world grapple with rising temperatures, these results provide critical insights for policymakers, urban planners and transportation experts seeking to create more resilient and equitable communities.

Heat waves lead to behavioral changes

On extremely hot days, people stay indoors significantly more often, resulting in less time spent on outdoor activities and non-essential travel. The study analyzed data from 11 major U.S. metropolitan areas and found that trips for leisure, shopping and socializing decline significantly as temperatures rise. Those who do venture out tend to schedule their trips to cooler times of day, opting for early morning or late evening excursions to avoid the midday heat.

Transport options also change significantly during heat waves. While car use is increasing, walking, cycling and public transport trips are drastically decreasing. In particular, public transportation usage drops by nearly 50% on days of extreme heat as people seek refuge in air-conditioned private vehicles. This shift poses significant challenges for cities that want to promote sustainable transportation options, especially as climate extremes increase.

Vulnerable populations bear the brunt

The study shows that certain groups face disproportionate challenges during extreme heat events. Low-income people and those without access to cars are more likely to rely on walking or public transportation, exposing them to dangerous temperatures. These individuals often have the least flexibility in when and where they work, requiring them to travel even in oppressive heat.

While those with higher incomes reported taking significantly fewer trips on extremely hot days, those with lower incomes and those without access to a car did not see a significant decrease in daily trips. This suggests that they are more vulnerable and exposed to the damaging effects of extreme heat. Older adults also face greater challenges adjusting their daily routines and risk social isolation when sheltering from the heat indoors.

Adapting urban environments for a warmer future

Given these findings, the researchers propose a series of policy recommendations to mitigate the impacts of extreme heat on communities. These include creating shaded public spaces, offering vouchers for on-demand door-to-door transportation to vulnerable populations, and declaring “hot days” during which people are encouraged to stay indoors and visit cooling centers if necessary.

Urban design improvements such as planting more trees and using heat-reflecting materials on sidewalks can also help make cities more resilient to rising temperatures. The study highlights the urgent need for cities to integrate heat mitigation strategies into their transportation and urban planning efforts to ensure all residents are protected from the dangers of extreme heat.

As extreme heat events become more frequent and severe, these results provide timely and actionable insights for creating more heat-resilient cities. By addressing the challenges associated with extreme heat through thoughtful urban planning and policy interventions, cities can work toward ensuring equity, public health, and well-being for all residents in an increasingly warmer world.