CANOGA PARK >> When summer heat rippled through her asphalt neighborhood last year, Maria Jimenez and her three young children sweated in their bottom floor apartment with the AC off to save cash.

But during one of the worst heat waves ever to hit Southern California this week, the Canoga Park family say they felt much better thanks to the first “cool pavement” street in the state.

“It’s cooler,” said Jimenez, whose two daughters translated her Spanish comments outside their Jordon Villa apartment, where they’d set up a portable pool in temperatures that reached a high this week at 104 degrees. “The heat is not so bad.

“Last year, it was horrible.”

It was late last month that Los Angeles, led by Los Angeles City Councilman Bob Blumenfield of the ultra hot southwest San Fernando Valley, launched an experiment in what could become L.A. cool.

• Related story: ‘Cool pavement’ to cut urban street heat gets first California tryout in Canoga Park

A light gray seal was splotched across a blistering half-block stretch of Jordan Avenue.

Since then, the battleship-gray reflective street surfaces have been added to short blocks in Arleta, Northridge and Hyde Park. Two more are slated to be laid down today in west Los Angeles, among 15 pilot projects across the city.

Their goal, city officials say, is to cut road temperatures, cool the insides of nearby buildings, lessen air pollution and reduce the threat of deaths linked to increasingly hotter heat waves.

If successful, the CoolSeal coating invented by GuardTop LLC could be added to thousands of miles of pending Los Angeles road upgrades.

In a city whose summer temperatures have risen an average 10 degrees in the past century because of miles of asphalt, parking lots, roofs and more, officials say the reflective roadways may help dial down an urban oven expected to be made hotter by climate change.

The gray streets could cost between $25,000 and $40,000 per mile and last five to seven years — a cost subject to change pending product and pavement innovation, city and GuardTop officials say.

After a week of roasting heat, three officials swooped down late this week to test the narrow street north of the Los Angeles River lined with two-story apartment buildings. By coincidence, each arrived separately after the sun peaked Thursday to gauge the effectiveness of the coating applied May 20.

Patrick Carrigan, an assistant engineer for General Services, pointed a handheld laser thermometer at the gray surface darkened by a month of road grime. It read 138 degrees. He then aimed it at the unpainted crossroad at Hart Street and Jordan Avenue.

“See look at that: 149 degrees, an 11-degree difference,” said Carrigan, on his second visit to Jordan Avenue, which he tested in addition to the three other reflective road sites. “The total average spread is about a 10-degree difference between black-to-gray.”

Blumenfield got similar results, as did a GuardTop executive who dropped by later with another handheld thermometer. Each recorded slightly higher temperatures toward the middle of the gray-painted street stained dark by tires and other road residue.

Two years ago, the councilman had passed a motion to test a new cool pavement that, with more trees and reflective rooftop solar panels, he thought could counter longer and extreme heat waves.

After rigorous testing of the CoolSeal coating for durability and wet skid potential, it was first applied at a Sepulveda Basin parking lot. Summer surface temperatures fell from 20 to 25 degrees.

“It’s great,” said Blumenfield, a former state assemblyman who arrived in a gray suit, blue shirt and fuschia tie. “It’s forward-thinking … it’s a vision for a cooler San Fernando Valley, Canoga Park and Los Angeles.

“It means health … life and death for people. It’s not an academic exercise. If we lowered the temperature in this community, it would mean cost savings for everyone inside and out.”

Among the rows of aging apartments with names like Jordan Villa, Jordan Casa and Jordan Terrace flanked by blooming magnolias or the occasional palm, residents said they already felt the cool.

“Now, it’s a few degrees cooler,” Jimenez said of her apartment. “We like it. If it wasn’t for this street, the heat wave would make my apartment hotter.”

“I feel a slight difference on the street and inside my apartment,” said Priscilla Corleto, 24, walking Gatsby, her small white Shih Tzu. “Without the AC, it seems cooler.

“It’s good. I like it. I think it’s a success.”