Uber, a start-up based in San Francisco, has won a following among urbanites with its novel twist on calling a car service: its app lets you summon a luxury sedan with a tap on your phone. Now it is trying to appeal to the less affluent by adding less luxurious cars.

In San Francisco and New York on Wednesday, Uber will start to give customers the option of choosing a hybrid car at a price that it says will be 10 to 25 percent more than a taxi.

Tags: apps, taxis