Bold of you to assume humans can walk outside in Phoenix.

Did you not read the article? It talks about this.

Imagine walking outside in an uninhabitable wasteland like Phoenix.

47°C in Phoenix this week. You're going to die outside regardless of how they paint the asphalt.

Absolutely. You would get double the dose, like skiing in a bathing suit. I've seen people come off the hill just fried because it's cool enough they don't notice getting burned to a crisp by the snow reflection.

it's in the article.

Also, Phoenix uses mostly white concrete for roads, it's too hot for asphalt.

Yes, but most of the time, on most of the street, there isn't a person or other object absorbing sunlight from both directions. So the vast majority of the heat that would've been absorbed into some kind of temperature increase in the road itself (and surrounding air and objects) gets rejected back into the sky/space, at the cost of a little bit more sunlight being absorbed directly by the cars and people who happen to be walking by.

I think the argument is that being hit by sunbeams from both sides causes less heat exposure than by the sun from above and asphalt that gets beat on by the sun and radiates heat back up.

I think I’ve seen other places use infrared reflective paint only to avoid excess heat and get similar results.