(Ben Schumin)In New York City, early adopters of the car-summoning smartphone app Lyft got a special gift: fifty free rides with a fare of up to $25 each in the first fifteen days that the service is open for business. It’s an impressive promotion…or it would be if there were any drivers available. In most cities where car-sharing services like Lyft and UberX operate, they recruit ordinary citizens with reliable cars and clean driving records.