An interactive web application that lets users explore and compare frequent transit service across any city with public GTFS data. Filter by minimum frequency (trips per hour) and minimum service hours to see only the transit routes that meet a defined quality threshold — revealing how much of a city's population is actually covered by reliable, frequent service. The app maps bus and mass-transit frequency alongside population density, calculates network statistics (coverage percentage, line count, median circuity, mean peak TPH), and includes a city-comparison tab with a dumbbell chart of frequent-vs-full coverage. Built from public GTFS feeds.