#KeepLACool: Cool Streets Reduce Urban Heat Island Effect

Posted by on Tuesday, May 29th, 2018

Word on the street is that cool streets are currently trending and will probably be trending until the end of the century. With heat projections from Dr. Alex Hall’s team at UCLA showing a triple increase in days over 95 degrees, the City of LA needs to embrace the diversity of urban cooling solutions available.

What are cool streets?
Cool streets are so named because they are literally cooler in temperature than traditional black asphalt streets. The material in cool pavement is similar to what’s used in sunscreen (not oxybenzone, the bad stuff you’ve been hearing about in relation to coral reef die-off!). Cool streets contain titanium dioxide, which reflects the sun’s energy back into the atmosphere as long-wave radiation.

Cool pavement can reflect up to 35% of solar energy, preventing this radiation from being absorbed and reemitted as heat into the surrounding urban area. In a city like Los Angeles, this can make a 20-40 degree Fahrenheit difference at ground level. Cool streets cost approximately $0.18 – $0.24 per square foot for one coat and $0.27 – $0.34 per square foot for two coats.

Presenting Path to Positive LA partner, Climate Resolve, has shepherd a pilot project with the LA Bureau of Street Services to install a cool street block—one block at a time—at each of the Council Districts in the City of LA.

How safe are cool streets?
Cool seal and pavements dry into a matte light gray color, which does not glare. The material has also passed the California skid test, making it just as safe to drive on as regular asphalt. At night, cool pavements reflect street lighting and car headlights, increasing visibility for drivers.

Why cool streets?
With endless miles of roads in Los Angeles, our existing infrastructure can be embraced as a vast arena of opportunity for mitigating urban heat. Cool streets can also help reduce greenhouse gas emissions; when the surrounding area is cooler, the demand for electricity for cooling will in turn decrease.

Plus, coupling cool streets and shade trees can help increase urban cooling. Trees provide shade and help maintain moisture in the soil. With a cooler environment surrounded by cool streets and shade-bearing trees, we Angelenos have the opportunity to thrive in a climate-smart city.

Path To Positive Los Angeles