Scope-safe generalization

Some city planners propose replacing dark pavement in public courtyards with pale, reflective paving. In a summer pilot, researchers paired 9 similar courtyards and resurfaced one courtyard in each pair. At midday, the resurfaced courtyards were an average of 4 degrees Celsius cooler than their paired comparison sites. Shade, wind, and visitor counts varied somewhat among the courtyards, so the researchers caution that paving color was probably not the only influence on temperature. Even with that limitation, the paired results make reflective paving a reasonable option for cities to test alongside trees and shade structures. The pilot did not measure winter conditions or neighborhoods outside the study area; consequently, it supports further local trials, not a claim that reflective paving will work equally well everywhere.