Division San Francisco’s streets by a suffix, road orientations, and names.
Coloring San Francisco’s streets by a suffix
The eastern part of the city comprises the original layout that was started in the 1840s and developed as the population grew. The western part of San Francisco was dunes and very few people lived out there. After the 1906 earthquake, there was a big population increase in that direction.
The neighborhoods there are the Richmond and the Sunset. Likely for ease of navigation the streets going east to west were all numbered. To distinguish them from the existing numbered streets in the eastern part of the city they were called avenues. The streets going north to the south out there were originally just given letters. In 1909 to make things easier for mail carriers they assigned names to the streets. If you look at a map you can see it more or less is alphabetical starting.
Mapping female versus male street names
Blue streets named after men, pink streets named after women.
Relative distributions of street orientations
San Francisco has grids partly tilted due to geography.