I established a shared design system and end-to-end task flows that mirrored real-world taxi operations, reducing taps and decision points for both sides. Driver UI emphasized glanceability and single-hand use in motion; the passenger app clarified ETA, driver identity, pickup instructions, and fare transparency to build trust. Interactive prototypes, store-ready screenshots/icons/descriptions, and a QA checklist bridged product, engineering, and marketing to ensure smooth releases and campaign readiness.