In New York City, the MTA (Metropolitan Transportation Authority) and the DOT (Department of Transportation) serve distinct but overlapping roles. The MTA is a state-run public benefit corporation responsible for operating the actual transit services; this includes the subways, public buses (NYCT), the Staten Island Railway, and commuter rails like Metro-North and the LIRR. If you have an issue with a train delay or a bus route, that is an MTA matter. The DOT, specifically the NYC DOT, is a city agency responsible for the infrastructure and the management of the streets themselves. They maintain the 6,000 miles of roads, the sidewalks, the bridges (like the Brooklyn Bridge), and the traffic signals. The DOT also operates the Staten Island Ferry and manages the city's bike lanes and "Better Buses" street designs. In short: the DOT builds and manages the "stage" (the streets and bridges), while the MTA runs the "performers" (the trains and buses) that move across it.