There is some evidence Uber's surge pricing is improving taxi markets. The firm says drivers are sensitive to price, so that the temptation to earn more is getting more Uber drivers onto the roads at antisocial hours. In San Francisco the number of private cars for hire has shot up, Uber says. This suggests surge pricing has encouraged the number of taxis to vary with demand, with the market getting bigger during peak hours.
However, the inflexibility of Uber's matchmaking fee, a fixed 20% of the fare, means that it may fail to optimize the matching of demand and supply. In quiet times, when fares are low, it may work well. Suppose it links lots of potential passengers willing to pay $20 for a journey with drivers happy to travel for $15. A 20% ($4) fee leaves both sides content. But now imagine a Friday night, with punters willing to pay $100 for a ride, and drivers happy to take $90: there should be scope for a deal, but Uber's $20 fee means such journeys won't happen.