Phoenix Heat Relief: Fixing Deadly Hot Bus Stops
The Challenge of Heat at Bus Stops in Phoenix
On a summer day in the Sonoran Desert, where temperatures often soar to 110 degrees Fahrenheit, waiting for a bus can be uncomfortable — even deadly. In 2023, at least 21 people died from heat exposure at bus stops in Phoenix, Arizona, according to data from the city’s health department. With over 4,000 bus stops across the city, only 77.5% currently have shade structures. While the city has pledged to add shade to each stop by 2050, recent studies suggest that not all shade structures are equally effective.
Assessing the Current Shade Structures
In 2017, Phoenix partnered with Arizona State University students to redesign its bus stops. The new design used perforated steel panels to optimize ventilation and reduce heat retention. It also aimed to prevent vandalism. The project won an award and began the manufacturing process. However, a 2021 study from Arizona State University raised concerns about the effectiveness of these designs.
The study found that while shaded bus stops reduced the "physiological equivalent temperature" (PET) by up to 38 degrees, the mean PET score was still 113 degrees — nearly 13 degrees above the acceptable thermal comfort threshold. About half of the riders surveyed reported feeling "hot or very hot." Additionally, man-made surfaces like concrete and metal benches reached temperatures as high as 111 degrees, which is at or above the skin-burn threshold.
Psychological factors also played a role. Riders at more aesthetically pleasing bus stops felt cooler, even when there were no significant changes in the surrounding environment. This suggests that design elements such as art, vegetation, and structure can influence how people perceive heat.
Innovative Strategies in Other Cities
Phoenix is not alone in tackling this issue. In Seville, Spain, a pilot bus structure uses solar panels to power a passive cooling system that circulates water beneath the shelter, reducing temperatures by up to 36 degrees. The structure costs approximately $30,566, compared to $18,500 for standard bus shelters in Phoenix.
In Florida, researchers are using artificial intelligence to assess heat exposure at bus stops. Xiang "Jacob" Yan, an assistant professor at the University of Florida, developed a "Transit Heat Exposure Index" to determine how hot it gets for people waiting for public transit. This helps cities prioritize upgrades to the most vulnerable areas.
Testing Reflective Materials
Arizona State University collaborated with 3M to test reflective film on bus shelter roofs in Tempe, a suburb of Phoenix. The material reflected sunlight and radiated heat skyward, making the area under the shelter cooler. Riders under the shelters with the film felt 2-4 degrees cooler than those without it. However, Tempe officials paused further testing due to limited resources.
Lessons from Phoenix's Light Rail System
Phoenix's light rail system, operated by Valley Metro, offers a model for other cities. Light rail stops have both vertical and horizontal shade structures, providing coverage during late afternoon and morning hours. These stations also incorporate drought-resistant trees and vegetation. However, light rail stops are fewer in number — only 28 across the metro area — compared to thousands of bus stops. This makes it more challenging to allocate resources for every single stop.
City-Wide Efforts and Challenges
Phoenix is evaluating a range of shade and heat mitigation strategies through partnerships with the Smart Surfaces Coalition and the National League of Cities. Valley Metro and the city also provide information on cooling centers and water locations. They distribute fans and sunscreen and train staff to recognize signs of heat illness. Last summer, the city spent about $3 million on broader heat response programs.
Despite these efforts, the system faces challenges. Heat-related emergency calls often involve individuals who have used drugs or alcohol. In 2023, 81% of the 21 deaths at bus stops involved substance use, which is significantly higher than the overall rate for heat deaths.
A Personal Perspective
Steve Drotman, an 84-year-old regular bus rider, relies on public transit due to declining vision. He chooses morning routes and wears a wide-brimmed hat to avoid the worst of the heat. However, he sometimes waits 30 minutes for a bus, searching for shade. Despite the challenges, he remains loyal to public transit.
Others are less positive. Some riders complain about late or missed buses, leading to long waits. Public transportation is also seen as slower than driving, with a 28-mile trip taking about 91 minutes. There is also a stigma that the system serves only the most vulnerable.
Phoenix's Vision for the Future
Despite these challenges, Phoenix aims to become the world's most sustainable desert city by 2050. This includes doubling the current tree and shade canopy to cover 25% of the city. Research shows that trees provide greater cooling benefits than shelters, reducing the risk of extreme heat.
During the record-breaking 2023 summer, a study in Tucson found that ground temperatures at bus stops without shade reached 124 degrees, while those with tree shade reached 108 degrees. This 16-degree difference can be critical for survival.
As Phoenix continues to improve its infrastructure, the goal is to ensure that all residents, especially those who rely on public transit, can navigate the city safely and comfortably. Every action taken to address heat exposure is a step toward a more equitable and sustainable future.
