So services like Lyft and Carshare may force San Francisco and other government agencies to rethink what a ride share is.

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The ingenuity lies in treating the ride-share as a logical addition to the transportation infrastructure.

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But his main point was that Europe had grown used to a free ride on American defence spending (which, as a share of GDP, is about three times the European NATO average).

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Carpooling, also known as ride-sharing or car-sharing, means that a group of people share one vehicle to get to work.

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