Colorado Public Works Journal, Summer 2023

SUMMER 2023┃15 CO/WY Chapter - ACPA @COWYACPA for sustainable pavements As global temperatures increase, reducing heat on roadways can help to lower emissions that contribute to climate change. The measurement of surface reflectivity is known as albedo. Lighter colored surfaces reflect more light, and have a higher albedo. Darker surfaces absorb more radiation and have a lower albedo. Surfaces that absorb heat keep temperatures elevated longer, releasing heat that keeps nearby areas hot even long after the sun has set. How is albedo measured? Albedo is a ratio expressed on a scale from 0 to 1. A surface with an albedo of 0 would be impossibly dark, taking in 100 percent of solar energy. A surface with an albedo of 1 would be completely reflective. How can albedo help mitigate climate change? Reflective pavements could lower air temperatures by over 2.5 degrees F and reduce the frequency of heatwaves by 41% across all U.S. urban areas. If all urban and rural roads in the continental U.S. were converted to higher albedo pavements, recent research found the GWP savings would equal 17 million tons of CO2 emissions per year — equivalent to removing roughly 4 million cars from our nation’s roads each year. For more information on albedo and concrete sustainability, refer to ACPA’s column in this issue of CPWJ. Choose concrete pavements to increase pavement albedo and help mitigate climate change! 17