"PTDC" is an application for public transportation riders. At the backend we use Public Transit Data Community API that provides us with aggregated real-time transit data from transportation agencies of District of Columbia, Virginia and Maryland. The application has three major features: - "Where Am I" - if you get lost in some neighborhood and don't know how to get home. This functionality is for you. It tells you what buses or metro lines is nearby your current GPS location, maps the routes on map and gives directions and arrivals for the stops. - "Next Transport" - It is a quick access to nearby arrivals. The list could be filtered by your favorite's stops and routes. - "Trip Planer" - that is a hit of the season. Build a trip from any places to any mixing transport operated by several transit providers.