It will depend very much on the types of location information passengers give, and routing flexibility they want. To give examples based on http://www.nytimes.

It will depend very much on the types of location information passengers give, and routing flexibility they want. To give examples based on http://www.nytimes.com/2014/11/10/t-magazine/london-taxi-test-knowledge.html http://www.nytimes.com/2014/11/10/t-magazine/london-taxi-tes... , consider "Take me to that gay bar near George Court", or how to bypass "construction that has sprung up on Regent Street." It also points out that currently "black cabs have triumphed in staged races against cars using GPS". Over time I have no doubt that more of this information will be in routing systems, but that's difficult to acquire, and crowd-sourcing attempts are subject to spamming.