Define the North Star metric for Maps serving commuters

Problem Statement Description

Product context: Google is a consumer technology, ads, AI, and cloud company; its products include Search, YouTube, Android, Maps, Gmail, Chrome, Google Play, Workspace, and Google Cloud.

Google Maps is used by commuters to navigate repeated trips such as home-to-work, work-to-home, school drop-offs, transit connections, and other routine weekday journeys. These users often care less about exploration and more about reliability: knowing when to leave, choosing the best route or mode, avoiding delays, and arriving on time with minimal stress.

In this metrics interview, you are being asked to define a North Star metric for Google Maps specifically for commuters. The metric should capture the core user value Maps provides in this context, while being measurable at Google scale across driving, public transit, walking, biking, and multimodal commutes.

Your answer should make clear what behavior or outcome the metric represents, who is included in the population, when a commute session counts, and how the metric would help product teams make decisions. You should also discuss why the metric is preferable to simpler activity metrics such as opens, searches, or route requests.

The experience should consider:

- How to define a “commuter” and a “commute trip” without relying only on explicit user labels.

- The numerator and denominator of the North Star metric, including what counts as a successful commuter outcome.

- Instrumentation needed across route planning, navigation, ETA updates, mode selection, notifications, and arrival confirmation.

- Key cohorts such as city density, transportation mode, weekday versus weekend, new versus habitual commuters, and regions with different data quality.

- Guardrail metrics for safety, privacy, route quality, user trust, battery/data usage, and over-personalization.

- How the metric handles cases where users check Maps without starting navigation or follow a familiar route without active guidance.

- How the metric can be used by teams working on ETA accuracy, routing, transit reliability, proactive alerts, and personalization.

- Potential failure modes where the metric could be gamed or improve while commuter experience worsens.

The goal is to define a decision-useful North Star metric that reflects whether Google Maps is genuinely helping commuters complete routine trips reliably and confidently, not merely whether they are engaging more with the app.