Making the switch between rider and machine safe and easy to read: a three-wheel electric moped with physical controls and a digital dashboard, designed for a rider with limited mobility. A team project in Interaction Design Fundamentals at Carnegie Mellon, Fall 2025.
I worked across the whole project with two teammates: framing the problem, building the physical controls, running usability tests, and designing the dashboard from low to high fidelity.
Semi-autonomy lives or dies at the handover: the moment the vehicle gives control back to a person, or takes it over.
This project was about making those moments safe and easy to read for a rider who can’t afford to be surprised.
Our brief was a semi-autonomous electric vehicle for one persona: Rose, an older woman who has difficulty walking long distances and worries about her safety when riding.
Two questions guided everything: How might we make Rose feel safe and free while navigating her neighborhood? And how might we use physical and digital design to help her feel supported when an emergency happens?
We chose a three-wheel electric moped, one wheel in front and two in back, so Rose can rest her legs while staying balanced and stable.
The controls that matter most live on the vehicle, not only on a screen: a Start button below the dashboard, a side panel for lights, hazard lights and a 911 call, and two handles with turn signals, throttle, brake, and a gear ring.
We also chose not to build a phone app: navigation and parking already live on the vehicle’s own screen.
Our first design made auto mode hard to trigger by accident: the rider pressed and held two finger icons on the handlebar while a blue ring filled on screen.
Testing broke it. None of our six participants found the control on their own. The placement was awkward (a Fitts’s law problem), the icons showed that something could be pressed but not how to use it, and waiting for the ring to fill was a safety risk at exactly the moment a switch mattered.
We replaced it with a gear ring on the left handle, with P, R, N, D and A positions, borrowing a pattern our riders already know: retired seniors who drive cars. Braking hands control back to the rider, and so does any obstacle the vehicle can’t avoid. After a switch, the mode letter in the status bar confirms it.
Hold two finger icons on the handlebar, then wait for a blue ring to fill before auto mode turns on.
Turn the gear ring on the left handle from D to A; the mode letter in the status bar confirms the switch.
Given Rose’s age and disability, we wanted a physical way to reach help. We first assumed it should be big and prominent. Testing showed people weren’t sure what the button did, why something used so rarely was so prominent, and why it sat next to the controls that started the vehicle.
Over four iterations we split and relabeled the controls. The final panel has a red 911 button that contacts emergency services and a separate toggle for the lights, including hazard lights. Red and clear icons carry the meaning, and the 911 button sits away from the main screen so it isn’t pressed by mistake.
In auto mode the moped manages speed, distance and navigation, and its speed and direction can change without Rose doing anything. So the dashboard keeps telling her what it’s doing.
A 3D view on the left shows the moped and the traffic around it. Short prompts in the corner say what the vehicle is doing: “Vehicle ahead, maintaining distance…”, “Slowing down…”, “Turning left, slowing down…”, “Stop sign ahead, slowing to a stop…”. Enough to keep her informed, never enough to distract her.
When the vehicle meets something it can’t handle, such as an obstruction ahead or a maintenance fault, it switches back to manual.
A large warning appears at the center of the dashboard in high-contrast orange or red. A triangle or wrench icon says what kind of problem it is, and a countdown tells Rose when she will be driving again.
We mapped that path too. If Rose takes over, she steers around the obstacle while the vehicle brakes. If she does nothing, the brake triggers automatically.
If the obstacle still isn’t avoided, the vehicle contacts emergency services with her location and tells her help is on the way.
Our mid-fidelity navigation screen had a microphone button so Rose could call for help or ask for assistance.
In testing, no participant noticed or used it, and we couldn’t find a clear, high-value use for it. We removed it in high fidelity to keep the screen focused on driving.
At the destination, the dashboard offers AutoPark and ManualPark. With AutoPark, the moped steers, brakes and positions itself while the screen keeps showing the map and speed.
With ManualPark, Rose shifts between drive, reverse and park on the gear ring, and a blue guide line on the ground helps her line up with the space.
The hardest part of this project wasn’t the interface. It was deciding what problem we were solving, and then letting testing overrule what felt obvious to us.