单选题   Para. 1 ①Economists have always been fond of Uber. ②Its willingness to battle incumbents, use of technology to match buyers and sellers, and embrace of 'surge' pricing to balance supply and demand make the ride-hailing giant a dismal scientist's dream. ③Steven Levitt, the author of the bestselling 'Freakonomics', called it 'the embodiment of what the economists would like the economy to look like'. ④But if economists subjected Uber and its competitors to a cost-benefit analysis, they might not be so impressed.
    Para. 2 ①This might surprise customers. ②A study by researchers from Oxford University, the University of Chicago and Uber itself found sizeable benefits from ride-hailing services for consumers. ③Using data from 48m Uber trips taken in four American cities, they estimated the difference between how much customers were willing to pay and their actual fare. ④Each $1 spent on Uberx rides generated a 'consumer surplus' of $1.60. ⑤Across America, that surplus was estimated to be $6.8bn a year.
    Para. 3 ①Drivers also benefit. ②Few sign up for lack of anything else, as is true of some gig work: in America roughly eight in ten have left another job to get behind the wheel. ③The typical American Uber driver makes $16 per hour ($10 after expenses), higher than the federal minimum wage. ④In London earnings after expenses come to 11 pounds ($14) per hour and a recent survey found Uber drivers reporting higher levels of life satisfaction on average than other workers.
    Para. 4 ①But against these benefits, there are costs to weigh. ②Far from reducing congestion by encouraging people to give up their cars, as many had hoped, ride-hailing seems to increase it. ③Bruce Schaller, a transport consultant, estimates that over half of all Uber trips in big American cities would otherwise have been made on foot or by bike, bus, subway or train.
    Para. 5 ①A new working paper by researchers from the University of Chicago and Rice University spells out one deadly consequence of this increase in traffic. ②Using data from the federal transport department, they find that the introduction of ride-sharing to a city is associated with an increase in vehicle-miles travelled, petrol consumption and car registrations—and a 3.5% jump in fatal car accidents. ③At a national level, this translates into 987 extra deaths a year.
    Para. 6 ①What could be done to tip the balance back to benefits overall? ②'Congestion pricing is the most direct solution,' says Jonathan Hall of the University of Toronto. ③Several cities, including London, Stockholm and Singapore, have moved in this direction, charging drivers for entering busy areas at peak hours. ④If ride-hailing firms tweaked their pricing to encourage carpooling, that would help, too.
    Para. 7 ①One of the worst things a city can do, says John Barrios of the University of Chicago, is to cap the number of ride-hailing cars on their streets, as New York did in August. ②That marked a step back towards the days when barriers to entering the taxi market were high and competition was low. ③A dismal outcome, as most right-thinking economists would agree.