A fare shake

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.