Pilot solution for Washington State's future infrastructure tax system
Munificence heroshot
Tongle is a cross-device prototype for the Washington's proposed Road Usage Charge policy.

With an increase in average fuel efficiency, funding roads with a gasoline tax is no longer sustainable. Washington State has proposed a per-mile tax based on miles driven, called the Road Usage Charge. In order to accomplish this policy, the state needs a way to verify the numbers of miles driven.

As a final deliverable, my team proposed Tongle, a cross-device system that records mileage and syncs the data with a paired phone app, which allows drivers to view, contest, and pay for their road usage. Our project has won several awards along with a grant.

Record locally.

Sync with the phone app.

Save people's phone batteries

The external device, plugged into a car's OBD-II port, records and stores a car's trip data. The ability to locally record mileage prevents large battery consumption as our research found that drivers don't want their batteries to drain due to the RUC mileage meter.

Sample view of of synced My Trip data
Sample view of of synced My Trip data

View, verify, and pay on your phone

Apply the proper per-mile rate

The coupled app allows users to view, contest, and pay for their road usage. They can also set up auto-payment cycle and method for their convenience.

Demo of viewing a trip detail and submitting a contest for an incorrect mileage record
Demo of viewing a trip detail and submitting a contest for an incorrect mileage record

Retain control of privacy settings

Respect drivers' privacy

Some drivers negatively perceived mileage recording as "being tracked by the government." To gain their trust, our design lets users enable GPS for specific trips and protect their privacy.

Tongle app with GPS enabled vs disabled
Tongle app with GPS enabled vs disabled

Design process

Building citizen-centered design

To end with these concepts, our team sat down with drivers from all over Washington State. Over the span of workshops, we together explored and evaluated different RUC methods. Our participants' perspectives revealed a core set of needs to be addressed in our designs. We used rapid prototyping method to build and iterate our design solution that sought to effectively address the tensions between those needs.

Our team and WA state drivers
Our team and WA state drivers had the span of workshops exploring and evaluated different design solutions
Affinity analysis of user needs found from the user research
We analyzed and grouped the user needs found from the user research. Some of the top values that WA drivers care are: accountability, privacy, convenience, and fairness.
Evaluations of past design solutions using the user needs
We then evaluated past design solutions using the user needs found in the affinity analysis
Design exercises and ideation with WA drivers
In the next session, we shared our research and facilitated design exercise in which drivers ideated solutions based on the user needs
Team whiteboarding on app interactions
After the design exercise, our team gathered to narrow down and refine design solutions

Friendly, trustworthy, and efficient

Developing visual identity

My secondary roles included developing a style guide and visual identity of Tongle. I aimed to create a visual look that conveys friendliness, trustworthy, and efficiency because many citizens tended to perceive tax systems as something complicated.

Tongle: project poster
Tongle quick style guide

Presentation and awards

We presented our project at the 2017 HCDE Capstone Open House, the biggest annual public event held by the department of Human Centered Design and Engineering. We also presented at the Smartphone Innovation Challenge held by the Mobility Innovation Center, the Washington State Transportation Commission, and select consulting team members.

Our project received positive reactions from both general public and our sponsors/clients. Along with a grant from the UW College of Engineering, we were awarded the Best in Show out of 14 HCDE undergraduate projects and Excellence out of 4 multidisciplinary (2 HCDE, 1 Informatics, and 1 Electric Engineering) capstone teams.

Munificence mood board snapshot
Project presentation poster
Presentation at 2017 HCDE Capstone Open House
Presentation at 2017 HCDE Capstone Open House
Presentation at Smartphone Innovation Challenge
Presentation at Smartphone Innovation Challenge
“The participatory design approach was really exciting.... Instead of government concocting a solution, and then trying to persuade others to logic of your solution, they worked with users throughout.”

— Jeff Doyle, a Partner at D’Artagnan Consulting


I want to give thanks to our sponsors and research participants for making this project possible. First time being introduced participatory design, I had opportunity to design with stakeholders throughout the project and share design thinking with non-designers.

While I am proud of how much my team has accomplished in 10 weeks, I wish we got chance to work with the developers and iterate our prototype based on technical feasibility. I would also like to look into Material Design or iOS guideline in order to better understand mobile design guidelines and improve visual design (visual hierarchy, more accurate usage of accent color).

View featured work

Heroshot of GEHC Edison™ Design System project
GE Healthcare Edison™ Design System
GEHC Edison™ Design System UI kit cover light theme
GE Healthcare Edison™ UI Kits
Heroshot of Munificence project
Heroshot of Tongle project