surroundings. The surface bounces the sun’s
heat upward into the atmosphere, but also
sideways toward buildings and pedestrians,
Levinson said.
Even when monitoring equipment shows lower
surface temperatures, people may feel warmer.
Reflected solar radiation will be absorbed by
people wearing dark clothing, while lighter
garments deflect sun rays. Tree shade and winds
dispersing heat can help improve comfort
levels, but an open lot or exposed street can
become unpleasant.
Sailor noted cool pavement was used on a
marathon route for the 2020 summer Olympics
in Japan, which was postponed because of the
coronavirus pandemic, but the solar reflection
likely would have made runners feel hotter even
with a lower surface temperature.
Despite higher costs than ordinary asphalt,
Sailor estimated cool pavement can result in
notable savings in Maricopa County, where
Phoenix is located.
“A single degree Fahrenheit reduction in air
temperature during the summer could save
residential ratepayers something like $75 million
per year in avoided air conditioning costs,”
Sailor said.
Murphy said the total cost of Phoenix’s pilot
program is $3.3 million from the city’s street
maintenance budget and primarily includes
materials and labor to cover 36 street miles
(58 kilometers).
The nine areas chosen were already due for
resurfacing and the money would have gone
toward rehabilitating those areas regardless of
the material used, she said.