The City of Phoenix Street Transportation Department selected portions of eight neighborhoods and one city park to receive cool pavement treatment as part of a pilot project. Cool
pavement is lighter in color than traditional asphalt or other seal coatings. Cool
pavement reflects back the sunlight that hits it. Because the surface reflects
rather than retains heat, cool pavement has the potential to offset rising nighttime
temperatures in Phoenix.
We are applying this cool pavement coating to extend the life of
existing pavement and allow us to study the effectiveness and durability of the
material. We have prepared this webpage to help answer some of the most common questions people may have about cool pavement and the city's pilot project.
What is cool pavement?
It is a water-based asphalt treatment that is applied on top of the existing asphalt pavement. It's made with asphalt, water, an emulsifying agent (soap), mineral fillers, polymers and recycled materials. It contains no harmful chemicals and is compatible with traditional asphalt.
Why would Phoenix apply cool pavement?
Asphalt collects and retains heat during the day and
releases it at night. Phoenix is among several cities that are experiencing the
urban ‘heat island’ effect due to the retention of heat within the built
environment. US Environmental Protection Agency data shows the difference in
nighttime temperatures in heat island areas can be as much as 22 degrees hotter
than temperatures measured outside the heat island. Higher nighttime
temperatures lead to more energy consumption, more greenhouse gas emissions,
air pollution and other harmful effects.
Cool pavement reflects back the sunlight that hits it.
Because the surface reflects rather than retains heat, cool pavement has the
potential to offset rising nighttime temperatures in Phoenix. The use of cool
pavement technology may help reduce the heat island effect and reduce
temperatures in the city. It is also useful to cool neighborhood areas that
don’t have much shade from the sun.
Phoenix participated in a workshop hosted by the federal
government and the City of Los Angeles. Los Angeles has been using cool
pavement on neighborhood streets and has reported positive results in reducing
roadway surface temperatures.
Why is this a pilot project?
The Phoenix Street Transportation Department is always
looking for ways to improve what we do and improve the livability of the city.
Phoenix wants to test the cool pavement technology and material to see whether
it is effective at reducing temperatures in Phoenix desert climate. We plan to
engage university researchers to take measurements and collect data over several years. They will evaluate the results and will hopefully help us
understand if the cool pavement product helps mitigate the heat island effect
and if those effects are sustainable over time.
We also want to see how the product holds up. Our climate is
unlike other major cities. We want to make sure it will last through our 300
days of sunshine, monsoon storms, high temperatures and daily traffic.
Where are you testing cool pavement?
The City of Phoenix Street Transportation Department
identified local streets in each Council District for cool pavement treatment.
Since different parts of the city experience different rain, monsoon
conditions, and degree of wear on the pavement, it should be a good way to find
out how well it is working and how durable it is.
The streets selected for this pilot project have asphalt
that is in good condition and where a preservative surface treatment would be
warranted. Preservative treatments extend the life of the road by sealing any
surface cracks to prevent moisture intrusion and improve the overall road
condition and appearance.
How can my neighborhood get cool pavement?
Before adopting this technology on a more widespread basis, we want to examine the results from the pilot program. Cost will also be a consideration, as the city works to use taxpayer funds wisely. While the cool pavement material is more costly than the seal coating materials we usually use, results from other cities suggest the material is effective and longer lasting than traditional asphalt seal coats. If that’s true in Phoenix, and the material provides the environmental benefits we believe it will, you can expect to see wider use of cool pavement when neighborhood streets are due for pavement maintenance.
Pavement condition is one of the key criteria for future installations. We will also try to solve community challenges such as providing heat relief to areas with very little shade. Future installations will be studied to ensure the cool pavement is placed equitably and in areas where the immediate benefit is most needed – such as areas with little or no shade or areas where people move on foot or bicycle out of necessity.
Can I buy the cool pavement material and treat my driveway with it?
As most Phoenix driveways are concrete, it's unlikely the product would work for you. The product is formulated to bond to underlying asphalt, and it’s also applied with specialized equipment over a larger area. There may be other types of coatings available – such as those used on concrete around pools – but they are probably not meant to handle vehicle movement.
Does cool pavement look different than traditional asphalt?
Yes. The cool pavement coating is a lighter grayish concrete color. This photo from Esteban Park gives a sense of the color.
The material dries to a matte finish.
Is cool pavement safe to use?
It is safe for all types of vehicles, pets, people and all
the typical activities that would take place on a road. Despite being lighter
in color, cool pavement does not result in glare. It also meets or exceeds skid
Is this a new product?
Colorized seal coats and asphalts have been around for a
while. Cool pavement uses existing material and technology in a new way.
How is cool pavement applied?
It can be sprayed or applied with a squeegee, just like the
other surface treatments we apply to city roads. Here you see crew members using squeegees to smooth the edges after the cart has applied the material. Below is a video of the cart applying the cool pavement material at Esteban Park.
Who are the partners in this project?
The City of Phoenix Office of Sustainability, the Street Transportation
Department and Arizona State University are partnering to see if this project
can help with the city’s continuing efforts to be environmentally sustainable
while improving the quality of life for all who enjoy Phoenix. We pledge to
keep you informed about this pilot project.
Is there a difference in skid resistance between regular asphalt and cool pavement?
We responded to a resident’s question about this by conducting a friction test jointly with the Arizona Department of Transportation (ADOT). The friction test is conducted at 40 MPH. While there are no established standards for skid resistance on 25 MPH neighborhood streets, the Street Transportation Department saw value in conducting a friction test as a baseline for future evaluations. The test measured friction in wet conditions. Staff found no safety concerns for people walking, driving or bicycling on streets coated with cool pavement.
When and where will you have study results?
We look forward to sharing the results of the study on this
website. Early results will be posted between now and the end of 2021.
Where can I see cool pavement?
The Street Transportation Department applied cool pavement to the parking areas and driveways at Esteban Park. See below for other pilot test locations and treatment schedules.
Associated Press Cool Pavement Article (this link will take you to the news site)
Arizona Republic Article from 5-15-2020 (this link will take you to the news site) Cool Pavement Street Cut Guidance
Cool Pavement Pilot Locations
QS: 11-30 – Van Buren St / Roosevelt St from 12th – 16th St Completed!
QS: 33-18 – Thunderbird Rd/Acoma from 47th- 43rd Ave Completed!
QS: 59-23 - Carefree Hwy / Languid Ln from OPEN SPACE / 27th Ln Completed!
QS: 29-37 – Shea Blvd / Cholla St from 40th – 44th St Completed!
QS: 11-22 – Van Buren St / Roosevelt St from 31st – 27th Ave Completed!
QS: 18-16 - Campbell Ave / Camelback Rd from 55th – 51st Ave Completed!
QS: 26-28 – Las Palmaritas Dr / Dunlap Ave from Central Ave to 7th St Completed!
D7 QS: 2-19 Vineyard Rd / Southern Ave from 43rd – 39th Ave Competed!
Esteban Park: 3345 E. Roeser Rd – Parking Lot Completed!
Project Hotline: 623-825-3444