There's I-10 that cuts through Phoenix east-west, I-70 that is north-south, and then they have built three highway loops that circle the city. The 101 is for the north/west part of the city, the 202 is for the south/east part of the city, and then the 303 is for the north/west part (way out there...).

https://www.google.com/maps/place/Phoenix,+AZ/@33.5083959,-1...

It was pretty nice when I lived there, because getting places using the highway was fast, and then the grid pattern for the rest of it made it incredibly easy to navigate.