Designing a scalable taxi service

Develop an architecture for a service similar in functionality to Yandex Taxi or Uber, designed for 100 million users and 1 million trips per month, assuming each driver makes an average of 30 trips per day. Users should be able to: place a taxi order, view a list of available cars, cancel an existing request. Drivers, in turn, should be able to: accept incoming orders, cancel them, and also find suitable orders.