Phoenix's reflective road coating cut surface heat by 12°F but raised radiant heat for pedestrians
Phoenix tried a reflective coating on black asphalt; noon surface heat fell 12°F
In 2020, Phoenix partnered with Arizona State University to test a reflective coating on some roads, aiming to reduce urban heat. A year-long study showed treated surfaces were up to 12°F cooler at noon, but the coating also reflected more sunlight back at pedestrians, raising mean radiant temperature by 5.5°F. The coating's reflectivity faded over time, and a follow-up review found it works best in open, low-traffic areas, not where people gather. Cities like San Antonio are also experimenting, but experts remain cautious.
Cooling a road surface and cooling the person walking on it are two different problems, and fixing one doesn’t automatically fix the other.
- downut
We moved to Tempe back around June 1987 and I had the summer off while the better half went to work. We moved from Gainesville, FL. One of us was raised in S. FL and the other GA. In Gainesville, we lived through the summers with an apartment and cars w/o AC. I worked in exterior renovation during one summer in Atlanta when it reached 100F regularly, and the summer after high school in S. FL installing attic HVAC metal ducts in new construction. So we thought we knew heat.
So I'm in the apartment in June and the complex has got a pool so like I'd always done I put the swimsuit on, grabbed a towel, and strode barefoot across the parking lot in the direction of the pool. It was probably 101F, nice day for June. About halfway across the lot I realized I was burning my (tough) feet. I'm a practical person and noticed the white stripes in the lot and ran to one. YUP! At least 20F cooler. Ever since I've wondered why you couldn't do something like that white paint for all the asphalt and concrete. Turns out you can. Hooray! I'm in Tucson now (it's currently 106F/22%). I'm out at 5AM for a bike ride many days and the lows have been steadily climbing over the past decades. Was 84F this morning, the lows increasing every day this week, YUK. When I ride out to the actual desert it gets noticeably cooler, maybe 5F. I want them to take this stuff and just coat the entire Tucson metro area with it.
[edited to add missing words]
- anigbrowl
Non-trash local source with actual photographs instead of AI-generated imagery
https://www.12news.com/article/news/local/arizona/phoenix-to...
- hankbond
I just simply don't understand why so many people live in Pheonix given the issues with heat and lack of water sources.
- 01100011
Meanwhile CA just passed zone zero regulations to defoliate the suburbs and increase the heat island effect while destroying wildlife habitats because we'd rather run scared than use better technology to fight wildfire risk...
Anyway, back to the story, I just saw this the other day: https://www.autonocion.com/us/target-mirror-panels-supermark...
- Animats
> Same street, two surfaces: Phoenix tested a reflective coating against regular asphalt (representative image). Image Credits: ChatGPT
Sigh. Fake pictures, plus internal links to the India Times.
The city of Phoenix has some web pages on this. There are pictures of the real coating, pictures of it being sprayed on, and links to technical studies. Phoenix has been doing this since 2021, gradually spraying more streets. It looks like grey paint but has asphalt in it.
Good idea, AI slop article.
[1] https://www.phoenix.gov/administration/departments/streets/i...