Product Sense: Urban Subway Design From the Rider's Point of View
Company: Coinbase
Role: Product Manager
Category: Product Design & Strategy
Difficulty: medium
Interview Round: Other
Design a subway system. Treat it as a product design problem: decide what the system is for and whom it must serve, identify where trips break down for those riders today, propose the core design and features, and explain how you would prioritize them and measure success.
```hint Start from the whole trip
Riders care about the journey from door to door, not only the train ride. Walk through each stage of that journey for one group of riders to find where a subway can make the biggest difference.
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### Clarifying Questions
- Are we building a subway for a city that has none, or redesigning an existing system, such as its fares, stations or rider information?
- What kind of city should I assume: a dense, congested metropolis, or a mid-sized city where most people drive today?
- Does my scope include network decisions such as routes and station locations, or mainly the rider experience on a network that planners define?
- Which outcome matters most to the city: ridership, less traffic and pollution, fair access across neighborhoods, or covering operating costs from fares?
### What a Strong Answer Covers
- A stated goal and scope, tied to the clarifications, with a north-star metric that follows from the goal.
- Rider segments with distinct needs, such as daily commuters, occasional riders and visitors, riders with reduced mobility and night-shift workers, plus a reasoned choice of focus.
- Pain points mapped to journey stages: planning, reaching the station, paying, waiting, riding, transferring and the last stretch to the destination.
- Prioritized solutions weighed against construction cost, capacity, accessibility and time to deliver.
- Success metrics with guardrails on safety, reliability, crowding and cost.
### Follow-up Questions
- With money for only one project, would you fund a line extension, more frequent trains on existing lines, or step-free access at every station? Why?
- How would you set fares so the system recovers more of its operating cost without pushing out low-income riders?
- A year after opening, ridership is well below forecast. How would you find out why?
Overview: A product sense prompt for product manager interviews that asks for the design of a subway system. It tests scoping, choosing rider segments, mapping pain points across the door-to-door journey, prioritizing features against cost and capacity, and defining success metrics with guardrails.