Great Circles

Designing an easy way to share a car among a group of friends.


Mobility is an important aspect of life and as a team of multiple nationalities, we realized that mobility in the U.S. was also strongly related to owning a car. Since half of our team comprised of international students, we were driven to solve this problem.


  1. Provide users with a simple record keeping system that, automatically tracks the time and fuel used, miles driven and the number of carpool riders.
  2. Support use of keys and car in a way that is natural and familiar to the users.
  3. Encourage sharing to let users reduce overall fuel consumption.
Understanding the user

In order to undersand and empathize with our users we conducted user interviews and online surveys.

User Personas


The brainstorming session helped us better understand the context. During this session we explored existing products, several interaction models and conceptual metaphors best suited for our context.


Problem Focus

In order to come up with a holistic design we decided to explore various design solutions that, incorporated our findings from the user interviews, the online surveys and the brainstorming sessions. After analyzing all the design solutions we were able to identify the merits of each idea which we later used to create our final design solution.

Initial set of ideas

Vision meets Design

As we refined our design ideas, we were able to identify three unique solutions.

  1. 'Key+' was an idea for a tangible smart key that would not only help users share the car effectively but also provide provide them with a sense of ownership.
  2. 'Wheelman' was an idea for a smart wristband that would work in parallel to an ipad app and easily notify users about the car.
  3. 'Great Circles' was a web app aimed at helping users easily view schedules and reserve the car prior to a specific event.
Getting feedback

We presented our design solutions at a HCI poster session held at Georgia Tech and received feedback that helped us better understand our users.

We also realized that Key+ was the concept that was better aligned to what our users needs and hence, we decided to use it in order to create our final design.

Initial wireframes

We identified the key use cases for the whole system and these are as shown below,

1. Quick check out

2. Join a ride Event

3. Add a user to an existing ride event

4. Monitor car usage

5. View schedule

Final designs

We validated our designs through peer evaluation which helped us iterate on the designs. We also built a higher fidelity prototype that was later tested out with our target users.

The three main aspects of the final solutions

The figure above displays the smart key fob (on the extreme left) that can be used as a clicker for the car window interface. This smart key had a car icon on the top and the color of this icon indicated the availability status (show in the image below) of the car. The image in the middle displays the car window interface (prototype built using web sockets and node.js). The image on the right displays a scheduler that users could use to schedule trips.

LEDs representing the availability status of the car

Due to lack of resources we decided to build a virtual smart key by using a smartphone (iphone). This revealed a lot of interesting aspects about the overall design however, due to the lack of tangible buttons the interactions were often delayed.

Prototype used for testing

My role

In this project I was primarily involved in designing the interactions, identifying the key use cases and creating a user testing protocol.

In order to know more about the concepts and design decisions taken in this project you could get in touch with me at writetoamrutha[at]gmail[dot]com.