Within the city limits of Phoenix, almost every street that runs true north-south is named via a number. The exception is Central Avenue, which is the zero number street that sits in the center of downtown Phoenix. North-South roads that are east of Central are either Streets, Places, or Ways, as in 1st Street, 2nd Place, and 3rd Way. North-South roads that are west of Central are either Avenues, Drives, or Lanes, as in 1st Avenue, 2nd Drive, and 3rd Lane.
Beyond 7th Street and 7th Avenue, the number system also indicates the distance away from Central. Every 8 numbers equals exactly one mile. Thus 16th Street and 32nd Street are precisely 2 miles apart. The exception is that 7th Street and 7th Avenue are also 1 mile apart.
The predominant north-south roads on the west side of town are odd numbered roads, like 19th Avenue, 35th Avenue, and 51st Avenue. On the east side of town, the predominant north-south roads are even numbered roads, like 24th Street and 40th Street.
East-West roads also are on the grid system, with major roads one mile apart, and with time in the city you tend to memorize which street is north or south of the other. Residents know that Thomas Rd is 1 mile south of Indian School Rd, which is 1 mile south of Camelback Rd. Washington St is the zero equivalent to Central Ave, where house number transitions from being North of to being South of. For example 100 N 1st Avenue would be about 1 block north of Washington on 1st Ave.
There are only a couple of major roads that don’t go perfectly north-south or east-west. Most notably is Grand Avenue, which runs at a perfect 45 degree angle to the grid layout North West from downtown Phoenix toward Wickenburg, Kingman, and Las Vegas. There is also Cave Creek Road, which runs North East from North Central Phoenix, meandering a bit to the town of Cave Creek. Cave Creek Rd breaks all the layout rules, as it meanders it’s way through the North Phoenix Mountain Preserve and never aligns with the grid.
A house number that is odd, is either on the south or east side of the street. A house number that is even, is then on the north or west side. For example, 100 S 2nd St is on the west side of 2nd St, while 201 E Thomas Rd is on the south side of Thomas.
City planners are so obsessed with the streets of Phoenix going perfect north-south and east-west, that there are “adjustments” at various points in the grid, to account for the curvature of the earth. Around Bell Rd and Baseline Rd, you’ll notice streets make this adjustment.
The neighboring cities around Phoenix all conform more or less to the grid, if not to the naming and numbering found in Phoenix. Most east-west streets retain the same name, however there are some exceptions. For example, Dunlap Ave becomes Olive Ave, once you get into the city of Glendale.
In the cities neighboring Phoenix, most name their major north-south streets with a name, rather than a number. Thus, Scottsdale Road runs north-south, rather than 72nd Street, as Phoenix would have called it. Although, adjacent to 72nd Street is still 71st Street and 73rd Street, so the non-number names are only for the major thoroughfares.