Design a Ride Sharing Service

Let's make an object-oriented design for a ride sharing service, the kind of app that connects a rider with a nearby driver.

A rider opens the app and asks for a car. Somewhere a decision gets made about which of the nearby drivers should be sent. Later another decision gets made about what the trip costs. Those two decisions are the whole question. Everything else is record keeping. The design is good or bad depending on whether the two rules can be changed without touching anything else.