Interesting to note that counting rides by a bounded geographic area is going to miss a lot, as the caltrain data doesn't seem to be represented in the santa clara data.
Also, the Austin data doesn't take into account that the city regularly expands its geographic boundaries (typically east and west) which may artificially make it seem as if it is increasing riders when it is simply absorbing them.
Since the current expansion started in 2010, the San Francisco tech industry has more than quadrupled in size to 100,644 tech jobs as of year-end 2018.
Also, the Austin data doesn't take into account that the city regularly expands its geographic boundaries (typically east and west) which may artificially make it seem as if it is increasing riders when it is simply absorbing them.