On a scorching summer day in Phoenix, Arizona, the Sonoran Desert’s relentless sun can turn a simple wait for the bus into a dangerous ordeal. Temperatures frequently soar past 110 degrees, and in 2023, this extreme heat proved deadly for at least 21 people at bus stops across the city, according to data from the city’s health department. With more than 4,000 bus stops dotting Phoenix, the struggle to keep riders safe from heat exposure is a challenge city officials are racing to meet.
Currently, 77.5% of these bus stops are equipped with shade structures, a figure the Phoenix transit department has pledged to bring up to 100% by 2050. But shade alone isn’t always enough. A 2021 study cited by Straight Arrow News found that while shaded bus stops reduced the so-called physiological equivalent temperature (PET)—the temperature as felt by the human body—by up to 38 degrees, the average PET in the shade still reached a blistering 113 degrees. That’s nearly 13 degrees higher than what’s considered the threshold for thermal comfort. Riders surveyed at these stops described themselves as feeling “hot or very hot,” and it’s easy to see why.
Concrete and metal benches exposed to the afternoon sun can heat up to 111 degrees or more, crossing the threshold where skin burns become a real risk. Phoenix’s 2017 partnership with Arizona State University students led to a redesign of bus shelters using perforated steel panels, aimed at improving ventilation and reducing heat retention. The new design even won an award and was hailed for its resistance to vandalism, according to city spokeswoman Carmen DeAlba Cardenas. Yet, the 2021 ASU study suggests that, while helpful, these structures don’t fully solve the problem.
Interestingly, the perception of heat isn’t just a physical phenomenon. The same study found that riders waiting at more aesthetically pleasing bus stops—those featuring thoughtful design, art, and vegetation—actually felt cooler, even if the microclimate hadn’t changed. It’s a reminder that how a space looks can affect how we feel in it, especially when the sun is beating down.
Phoenix isn’t alone in searching for solutions. In Seville, Spain, a futuristic pilot bus shelter uses solar panels to power a passive cooling system that circulates water beneath the structure, cooling waiting areas by up to 36 degrees. The catch? Each shelter costs about $30,566 in U.S. dollars. By comparison, Phoenix’s bus shelters come in at $18,500 apiece, according to Cardenas.
Other cities are also innovating. In Miami, researchers from the University of Florida have developed a "Transit Heat Exposure Index" to pinpoint bus stops where the risk to riders is greatest. As Xiang “Jacob” Yan, an assistant professor at the university, explained to Straight Arrow News, this data-driven approach helps cities prioritize where to add shelters and even tree canopies, not just at stops but along the pathways leading to them.
Closer to home, a collaboration between Arizona State University and 3M saw the testing of a reflective film on bus shelter roofs in Tempe, just outside Phoenix. The film worked by reflecting the sun’s energy and radiating heat skyward, cooling the area beneath by 2-4 degrees. But further testing was put on pause as Tempe officials shifted their focus to simply increasing the number of shelters at unshaded stops, citing limited resources.
Phoenix’s light rail system, operated by Valley Metro, offers another model. Its 28 stations—far fewer than the thousands of bus stops—feature shade structures with both vertical and horizontal elements, providing more coverage throughout the day. Drought-resistant trees and vegetation are also part of the design. According to Valley Metro planner Arden Holloway, these improvements come with a hefty price tag, making it tough to extend them to every bus stop in the sprawling metro area.
When it comes to heat-related emergencies at bus stops, the risks are compounded by other factors. In 2023, 81% of heat deaths at Phoenix bus stops involved substance use—well above the citywide rate for heat deaths. Most of these tragedies occurred during the peak summer months of June through August, and a whopping 78% happened on days when temperatures hit 110 degrees or higher.
Despite the dangers, many Phoenix residents rely on public transit. Steve Drotman, an 84-year-old regular rider, has adapted by choosing morning routes, donning a wide-brimmed hat, and avoiding the harshest sun. "I love every day that I get on the bus," he told Straight Arrow News. Still, for others, the system’s shortcomings—delays, infrequent service, and the stigma that public transit is only for the “poorest of the poor”—make for a less-than-ideal experience. The presence of unhoused individuals at bus stops, seeking shelter from the sun, often leaves actual riders exposed and waiting in the heat.
Yet, Phoenix’s fixed-bus routes logged more than 28 million boardings in the 2025 fiscal year, showing just how vital the system is. City leaders have an ambitious vision: by 2050, they hope to double the tree and shade canopy to cover 25% of Phoenix, aiming to become the world’s most sustainable desert city. Research from UTHealth Houston supports this approach, finding that trees offer greater cooling benefits than shelters alone and are linked to a lower risk of extreme heat exposure.
The difference trees can make is stark. During Arizona’s record-breaking summer of 2023, a study in Tucson measured ground temperatures at bus stops around 2 p.m. In areas without shelter or vegetation, the ground hit 124 degrees. Where tree shade was present, it was a much more bearable 108 degrees—a 16-degree difference that could mean the difference between comfort and crisis for those waiting on the bus.
City officials aren’t sitting idle. Last summer, Phoenix spent about $3 million on heat response programs, according to Valley Metro spokeswoman Susan Tierney. Valley Metro has also improved air-conditioning on buses and launched an app offering real-time arrival schedules so riders can minimize their wait outdoors. "We advise people to time the arrival of a train or a bus so that they are limiting their wait outside," Tierney noted. The city has also partnered with organizations to provide information about cooling centers and water stations, and distributes fans and sunscreen to help protect the most vulnerable.
Looking ahead, Phoenix is evaluating a wide range of shade and heat mitigation strategies for outdoor environments, working with groups like the Smart Surfaces Coalition and the National League of Cities. While no new pilot programs for bus shelter cooling are in the works just yet, the city is clearly exploring every avenue to find relief for its residents.
Remarkably, even as August 2025 is on track to be the hottest on record in Phoenix—with nearly every day topping 110 degrees—heat-related deaths are expected to be lower this year than in previous years, according to recent reports. It’s a glimmer of hope that the city’s efforts, both big and small, are starting to make a difference for those who depend on public transit to get around.
