Pavement Treatment Practices and Dynamic Albedo Change in Urban Pavement Network in California

Recognizing the potential for cool pavements to reduce greenhouse gas emissions and to improve heat islands and air quality, local governments in California are beginning to adopt cool-pavement strategies in their climate action plans. Reflective pavement is one cool-pavement strategy and uses high albedo to reduce temperature. This paper details the results of a pavement management survey, the albedo of pavement treatment materials, and dynamic modeling of the albedo of public pavements for various local governments in California. This information is intended for use in a life-cycle assessment tool for an urban heat island and for inputs into climate modeling during the use phase for that tool. Key findings include the following. First, most local governments treat a small portion—ranging from 1.3% to 20%, with an average of 7% for the eight local governments studied—of the pavement network of public streets every year. Second, slurry seal and asphalt overlay are the two major treatments used, with an average of 41% and 37% of mileage treated, respectively. Third, most pavement treatments currently used have relatively low albedos, ranging from 0.05 to 0.15, with an average of 0.1 for asphalt concrete, and from 0.1 to 0.24, with an average of 0.15, for chip seal. Albedos for cape seals and slurry seals range from 0.06 to 0.15, averaging 0.12. Finally, because of the small portion of typical pavement networks currently having treatments of relatively low albedo applied every year, the average increase of urban pavement network in the 50-year analysis period is relatively low, ranging from 0.02 to 0.12.