We have received a similar question twice before and you might find it interesting to see what we answered at that time. With maps now available on the Internet you can see the layout of Phoenix and perhaps find the answer yourself. I used the map service on Google to find a map of Phoenix.
The scale that comes up is a little too small. If you look in the lower left corner the scale is for 2 miles. If you move the slider that is above the scale up one notch you will zoom in and the scale will show 1 mile. What I see is that some of the major roads are approximately 1 mile apart so you can count the blocks. In Phoenix, as in many cities, the count is different going north and south than it is going east and west.