"P" is for PRICE ELASTICITY OF DEMAND. "C" is for CONSUMER SURPLUS. "U" is for UPFRONT PRICING. Taxi and Uber rides are in HIGH DEMAND when one is in a hurry to a meeting, school or airport. In such situation, our DEMAND FOR A RIDE is VERY PRICE INELASTIC. Higher prices would not discourage us from using a taxi as much as they would in a non-rush situation. This new UPFRONT PRICING strategy of Uber utilizes this concept and allows people to GET A HIGHER CONSUMER SURPLUS by reserving rides much in advance.