← No. 033 SUN 01 NOV 2026

Reflective roads cool the ground more than the air.

Reflective pavement — Phoenix, Arizona

Two 2026 field studies in Phoenix tested reflective street coatings at scale. Pavement surfaces cooled by as much as about eight degrees, and soil below by three to four. Air at head height fell only a little, usually half a degree or less, with the biggest drops late in the day. In full sun at midday, radiant heat on the body was higher. At one site the coating’s brightness halved over 21 months.

Why it’s interesting

Fig. 033 Incoming and reflected light over a cooled road encode strong surface cooling, slight air cooling, and a sunlit midday rise in radiant load; 0.58/8.3 marks air‑to‑surface cooling from the 2026 Phoenix studies.

Why it’s interesting

It separates what the ground feels from what people feel. Cooling the surface does not guarantee cooler bodies at noon, and the coatings’ brightness can fade fast enough to matter for maintenance and planning.

The longer version

Reflective coatings aim to push sunlight away so pavements don’t soak up as much heat. Two 2026 Phoenix field studies tracked not just surfaces but the air people breathe and the radiant heat that strikes the body. They found strong surface cooling (averages near 3 °C, peaks around 8 °C) and cooler soil beneath, but only modest cooling of air at pedestrian height, typically around half a degree or less and strongest late day.

Both studies also measured a trade‑off in the sun: higher midday mean radiant heat above reflective pavement, which can feel harsher despite the cooler surface. One site’s solar reflectivity faded by roughly 53% over 21 months, echoing city program measurements of early decline. Together, these in‑situ results ground expectations for when and where such coatings help with heat and comfort.

Edition: No. 033
Date: Sunday 1 November 2026
Subject: Reflective pavement
Locality: Phoenix, Arizona
Period: 2026
Field: earth
Evidence: 4 sources, 2 primary

See how we got here

Found after 16 research paths · Selected from 6 candidates

01 Urban heat Cities store daytime heat and stay warm at night.
02 Reflective pavements Brighter roads send more sunlight back to the sky.
03 Phoenix trials Large, real‑world coatings monitored through 2026.
04 Surface vs air Big surface drops, small air changes measured.
05 Midday radiant heat Sunlit bodies saw higher radiant load above coatings.
06 Fading brightness Reflectivity fell by ~53% over 21 months at one site.
→ Reflective roads cool the ground more than the air.

Sources

Nothing publishes without independent sources. How we verify →

1
Beyond surface cooling: Comprehensive field assessment of reflective pavement thermal performance in Phoenix, Arizona (Building & Environment, 2026)
Arizona State University · 2026 · university Primary

Air-temperature reductions ~0.2–0.35 °C; subsurface cooling ~3–4 °C at 7.6 cm; midday T_MRT increase 2.4–3.0 °C; Phoenix field setting; publication date 2026‑04‑15.

asu.elsevierpure.com
2
Thermal impacts of large-scale cool pavement: Field results and methodological insights for urban climate studies (Urban Climate, 2026)
Arizona Board of Regents · 2026 · university Primary

Max surface cooling 8.3 °C; subsurface cooling up to 3.9 °C; T_air reductions up to ~0.58 °C; reflectivity loss 53% over 21 months; Phoenix field setting; publication date June 2026.

experts.azregents.edu
3
Cool Pavement Program page
City of Phoenix · 2021 · government

Government documentation of Phoenix cool‑pavement program and measured reflectivity decline from 33–38% to 19–30% in ~10 months (consistent with degradation trend).

phoenix.gov
4
Evidence‑based guidance on reflective pavement for urban heat mitigation in Arizona (Nature Communications, 2023)
Nature Research (Open Access via PMC) · 2023 · peer reviewed

Independent, peer‑reviewed corroboration that reflective pavements lower surface temperatures, have modest air‑temperature effects, and can raise midday T_MRT in sun.

pmc.ncbi.nlm.nih.gov

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