California Governor Jerry Brown has signed Assembly Bill 296, which calls upon the California Department of Transportation to develop a standard specification for sustainable or cool pavements that can be used to mitigate urban heat islands. Cool pavements absorb less sunlight than conventional pavements, helping reduce surface and air temperatures in cities. The new specifications for cool pavements will complement and support the existing voluntary standards for cool pavements in the California Green Building Code. The legislature heard testimony from Berkeley Lab scientists, and consulted Environmental Energy Technologies Division research studies on the science of cool pavements during the bill’s development.
Art Rosenfeld, Scientist Emeritus in Berkeley Lab’s Environmental Energy Technologies Division, helped establish a research group that pioneered the study of urban heat islands. Their work shows that lighter-colored roofs and pavements can reduce smog, cut energy consumption and cool urban areas, and mitigate the impacts of global warming.
“As the rate of smog formation is extremely sensitive to increasing heat, cool pavements will improve air quality and lessen this serious public health threat,” Rosenfeld said. “Expanding use of alternative pavements will keep summers more comfortable for inland cities from Riverside to Pleasant Hill, and minimize the increasingly frequent heat waves in urban areas.”
Cool roofs and pavements can also help mitigate global warming. Based on research by the EETD group, as existing pavements across California need resurfacing, a switch to concrete (or other reflective competition)—at little or no cost—would offset the annual emissions of more than 10 million metric tons of carbon dioxide (CO2) for the 15-year service life of the pavement. (One metric ton is about 2,200 pounds.) This amount is equivalent to taking more than 2 million cars off California roads for 15 years.