Also listed are the historic companies which had previously operated the bus and streetcar systems in each city, and years of last streetcar, and first and last trolleybus. Also mentioned are systems with rapid transit lines and new "light rail" lines.
Most transit systems became publicly owned around the 1970's. Typically, a privately owned system was a "company" or "Co.". While a publicly owned system would be an "Authority" or "District" or "System". Some publicly owned transit systems began as city systems, but later expanded into regional systems, as indicated. And some publicly owned transit systems were simply renamed for marketing reasons.
For most states, in addition to major metropolitan areas, transit systems are divided into two groups, or two web pages. Following the major metropolitan areas, the first group for each state are generally cities or clusters of cities with a 1940 Census population of at least 25,000. And included are certain cities which experienced phenomenal growth into larger cities, such as Las Vegas. Also included are state capital cities and cities with major universities, with a long history of public transportation. In these cities, traditional fixed route bus systems typically continue to exist.
The second group for each state are the smaller cities. Where public transit survives, many of these smaller transit systems eventually evolved to dial a ride operations, no longer with scheduled fixed routes. Some dial a ride systems are only available to people with disabilities or to senior citizens.
For the larger cities, web links are provided for the present day transit systems. Web links are not included for the smaller transit systems, as that has proven to be too complex due to many changing links.
American Public Transportation Association
Web site includes links to most transit systems throughout the United States. Although some information is out of date. Most of the main pages for each individual state include links to statewide web sites, with links to transit system web sites. This might typically include a state government Department of Transportation, or a Public Transit Association which is normally a trade organization of the transit systems within a state. All of these web sites can aid in identifying present transit systems serving smaller cities.
Many transit systems now have Wikipedia pages, which include history and fleet and additional information. Each page usually can be found through a Google search. But of course any information on the Web, including this web site, cannot be solely relied on for all of the absolute facts.
Next to certain company names in parentheses are holding companies, ultimately owning a particular company.
Streetcar companies are mentioned in the Moody and the Poor investment manuals, and "The Trolley And Interurban Directory", by Joseph Gross. But it is possible, that some streetcar systems failed to be completed, and were never actually operated.
In addition to the traditional city transit systems which started out as streetcar systems, there existed a number of independent suburban bus lines, which in many cases have basically been forgotten. But the 1952 "Mass Transportation's Directory" provides an interesting "snapshot", of what obscure bus companies had coexisted with the main transit providers.