Taxis wait in London in June 2014. By law, the drivers of London's black cabs must memorize all of the city's streets, a process that takes years of study. The taxi drivers are opposed to Uber and drivers using a GPS, but the High Court ruled in favor of Uber last week. Oli Scarff/Getty Images hide caption

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Traffic stands still in Nairobi. People in Kenya's capital don't like getting into cabs driven by strangers. They prefer to call drivers they know or who their friends recommend. Goran Tomasevic/Reuters/Landov hide caption

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Seattle's government has given early approval to caps on ride-share companies such as Uber. Here, Peter Faris, whose company's drivers use Uber to find customers, holds a smartphone with the ride-sharing company's app in Washington, D.C. Paul J. Richards/AFP/Getty Images hide caption

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