Your market valuation puts the average fare in the region of $100, the linked document (page 10) says "The average yellow taxi fare in 2013 was $13.40" so I'm n

Your market valuation puts the average fare in the region of $100, the linked document (page 10) says "The average yellow taxi fare in 2013 was $13.40" so I'm not so sure the market is $20bn, I'd guesstimate somewhere around $3-5bn for the vehicles they mention in the article.