During the nine months before Google announced it would release detailed street maps for New York, London, and San Francisco, fragments of sidewalks and patches of grass and vegetation appeared on Google’s maps of these cities.

In November 2019, for example, fragments of sidewalks appeared for several blocks in San Francisco’s Hayes Valley neighborhood:

And over the next several months, small patches of grass and vegetation appeared throughout Google’s maps of San Francisco, New York, and London:

In hindsight, these vegetation and sidewalk fragments were clues that Google was preparing to release detailed street maps for these cities.

And now, as of January 2021, we’re starting to see vegetation and sidewalk fragments appear in several new cities, including Austin, Boston, Chicago, Paris, and parts of suburban Phoenix (examples below).

The appearance of these shapes in suburban Phoenix is particularly interesting because it’s occurring in the same area where Waymo One (Google’s autonomous vehicle project) is currently operating:

This suggests Google’s detailed street maps and its autonomous vehicle projects might be related.