Text 1 It is a familiar ritual for many:after a late night out you reach for your smartphone to hail an Uber home.only to find-disaster-that the fare will be three times the normal rate.Like many things beloved by economists,"surge pricing"of the sort that occasionally afflicts Uber-users is both efficient and deeply unpopular.From a consumer"s perspective,surge pricing is annoying at best and downright offensive when applied during emergencies.Extreme fare surges often lead to outpourings of public criticism:when a snowstorm paralysed New York in 2013,celebrities,including Salman Rushdie,took to social media to rail against triple-digit fares for relatively short rides.Some city governments have banned the practice altogether:Delhi"s did so in April.Surge（or dynamic）pricing relies on frequent price adjustments to match supply and demand.Such systems are sometimes used to set motorway tolls（which rise and fall with demand in an effort to keep traffic flowing）,or to adjust the price of energy in electricity markets.A lower-tech version is common after natural disasters,when shopkeepers raise the price of necessities like bottled water and batteries as supplies run low.People understandably detest such practices.It offends the sensibilities of non-economists that the same journey should cost different amounts from one day or hour to the next-and more,invariably,when the need is most desperate.Yet surge fares also demonstrate the elegance with which prices moderate a marketplace.When demand in an area spikes and the waiting time for a car rises,surge pricing kicks in;users requesting carsare informed that the fare will be a multiple of the normal rate.As the multiple rises,the market goes to work.Higher fares ration available cars by willingness to pay:to richer users,in some cases,but also to those less able to wait out the surge period or with fewer good altematives.Charging extra to those without good alternatives sounds like gouging,yet without surge pricing such riders would be less likely to get a ride at all.since there would be no incentive for all the other people requesting cars to drop out.Surge pricing also boosts supply,at least locally,The extra money is shared with drivers,who therefore have an incentive to l:ravel to areas with high demand to help relieve the crush.Whether Uber remains a big part of the transport network in future,and whether it retains surge pricing,depends in part on how well local govemments manage the transport system as a whole.In other words,surge pricing is really only as painful as local officials allow it to be.24.The cause of surge fares in automobiles lies in