...and 10% of John's rides are to an address whose only tenant is a drug addiction rehab clinic, but he apparently doesn't work there because 50% of his rides are from a tech company's headquarters to his home late at night. So it looks like John may have a little bit of a drug problem.
You can find out a lot of personal information about someone by tracking where they go on a regular basis.
Yep, once I plotted my Google location history and played this game looking at my "hot spots". Even if you work at a large company and don't go to special places it's very easy to gather insight by looking, for instance, where a person goes in certain dates: he spends Christmas in this village, he stays home in Valentine's day, etc.
You can find out a lot of personal information about someone by tracking where they go on a regular basis.