As defined by the US Census Bureau, a metropolitan area always consists of one or more whole counties, where there is a significant amount of travel and commerce throughout the area, and to or from a main city. In the New England, where every area is part of an incorporated city or town, and where the counties are less significant units of government, the Census Bureau formerly had designated metropolitan areas which included only portions of various counties. But the Census Bureau recently discontinued this practice, and now all metropolitan areas in the six New England states consist of whole counties.
Baltimore, St. Louis, and Carson City Nevada are actually independent cities, which for these purposes, could just as easily be counted as counties. Just as the case with Philadelphia, San Francisco, and the five boroughs of New York City, each of which is officially a county by itself. In Virginia, every incorporated city regardless of size is an independent city, but only the ten largest cities are considered large enough to be counted as counties for the purposes of these pages.
Some counties near a state line are actually part of a metropolitan area where the main city is in a different state. These are mentioned only in the rare situations where transit systems actually make interstate connections. Or else where a county lacks a significant city of its own, and it is necessary to identify the metropolitan area by the main city in the other state.
The US Census Bureau has also defined the "Combined Statistical Area", which consists of two or more adjoining metropolitan areas, where there is some degree of travel and commerce between those areas. These are only mentioned where there is some degree of connectivity between the transit systems.
In recent years, the US Census Bureau has adopted a new definition, the "Micropolitan Statistical Area", which is smaller than a typical metropolitan area, but nevertheless statistically significant in various respects. Nearly all cities which have historically had public transportation, are now either in metropolitan or micropolitan areas. Which makes it easier to trace the justification of the existence of public transportation.
Further information is available at the US Census Bureau Web site.
Types Of Transit Systems
Fixed route - A regularly scheduled bus service operated along an established route. Typically operates in cities and developed urban areas, no reservation is needed.
Dial-a-ride - A transit service, usually using vans, where passengers are transported anywhere they wish within the service area. A dispatcher, sometimes aided with computer software, must determine the most direct and efficient route, based on passenger pickup and drop off requests. Typically operates in rural areas and smaller towns, or to serve people with disabilities and senior citizens, and requires advance reservations.
Route deviation service - A hybrid between fixed route and dial-a-ride service. A bus or van will operate over a general route, but will deviate off the route to serve a specific location requested in advance.
Transit Service Definitions For These Pages
In describing the connections available between transit systems listed in these Web pages, the following definitions are used:
Primary urban transit system - The established transit system serving the main city or county in a metropolitan area.
Connecting fixed route system - A transit system with scheduled fixed routes, primarily of an urban nature, which makes connections with a primary urban transit system, usually near a county line or a border between the transit systems' jurisdictions.
Isolated fixed route system - A transit system with scheduled fixed routes, where none of the routes connect with a primary urban transit system.
Connecting rural system - A rural type transit system, usually a dial-a-ride or occasionally a route deviation service, where connections are advertised with a primary urban transit system, usually near a county line or a border between the transit systems' jurisdictions.
Rural system - A rural type transit system, usually a dial-a-ride or occasionally a route deviation service, which is not intended to connect with a primary urban transit system or enter the main city, except for some such systems providing weekly or infrequent service into the city primarily for doctors' appointments.
Commuter service - A bus service which operates express between an outlying suburban area and the main city downtown, usually during rush hours only, and is typically operated separately from or in addition to the other types of transit systems described above.