Requirements of Uber’s Design

Requirements

Let’s start with the requirements for designing a system like Uber.

Functional requirements

The functional requirements of our system are as follows:

• Update driver location: The driver is a moving entity, so the driver’s location should be automatically updated at regular intervals.

• Find nearby drivers: The system should find and show the nearby available drivers to the rider.

• Request a ride: A rider should be able to request a ride, after which the nearest driver should be notified about the rider’s requests.

• Manage payments: At the start of the trip, the system must initiate the payment process and manage the payments.

• Show driver estimated time of arrival (ETA): The rider should be able to see the estimated time of arrival of the driver.

• Confirm pickup: Drivers should be able to confirm that they have picked up the rider.

• Show trip updates: Once a driver and a rider accept a ride, they should be able to constantly see trip updates like ETA and current location until the trip finishes.

• End the trip: The driver marks the journey complete upon reaching the destination, and they then become available for the next ride.

Non-functional requirements

The non-functional requirements of our system are as follows:

• Availability: The system should be highly available. The downtime of even a fraction of a second can result in a trip failure, in the driver being unable to locate the rider, or in the rider being unable to contact the driver.

• Scalability: The system should be scalable to handle an ever-increasing number of drivers and riders with time.

• Reliability: The system should provide fast and error-free services. Ride requests and location updates should happen smoothly.

• Consistency: The system must be strongly consistent. The drivers and riders in an area should have a consistent view of the system.

• Fraud detection: The system should have the ability to detect any fraudulent activity related to payment.

Resource estimation

Now, let’s estimate the resources for our design. Let’s assume it has around 500 million riders and about five million drivers. We’ll assume the following numbers for our estimates:

• We have 20 million daily active riders and three million daily active drivers.
• We have 20 million daily trips.
• All active drivers send a notification of their current location every four seconds.

Storage estimation

Let’s estimate the storage required for our system:

Rider’s metadata

Let’s assume we need around 1,000 Bytes to store each rider’s information, including ID, name, email, and so on, when the rider registers in our application. To store the 500 million riders, we require 500 GB of storage:

$${500 \times 10^6 \times 1000 } = 500\ GB$$ ...