The second effect of surge pricing was to allocate rides to those that value them most. Figure 3 shows that, while the number of app openings increased dramatically, the number of actual requests didn’t increase by as much. This came from riders who opened the app, saw that surge pricing was in effect and decided to take an alternate form of transportation or chose to wait for surge pricing to end. From an economic efficiency standpoint, this was highly beneficial because those that ended up requesting a ride are those for which their outside option was worse, leading them to value Uber more in that particular moment. The gap between the red and blue line could be tentatively interpreted as a measure of this allocative efficiency.
Allow me to translate: people who couldn't afford surge pricing didn't take Uber, while those wealthy enough to be indifferent to price still did. Surge pricing is thus not as much a means to increase capacity as it is to get the huddled masses out of the way of the 1%.