This seems like an easy question on the surface. Public transit is there to provide transportation options that are available to everybody. However, there are many ways to do this and the exact goals that public transit agencies try to address will be different depending on their policies and priorities.
For example, some might strive to make sure that their whole territory has service so that people could get from any part of the region to any other. Others might try to attract the most riders by competing with cars for commuter trips. And yet others might aim to enhance economic development, improve quality of life, reduce emissions, improve public health, provide the most efficient service possible, or meet any number of other public policy objectives.
Take for example two mission statements from large public transit agencies on opposite sides of the country. The New York MTA mission statement is:
“The MTA preserves and enhances the quality of life and economic health of the region we serve through the cost-efficient provision of safe, on-time, reliable and clean transportation services.”
Meanwhile, the Los Angeles Metro’s statement is:
“Metro is responsible for the continuous improvement of an efficient and effective transportation system for Los Angeles County.”
Clearly, the MTA has a wider mission statement than Metro and although these are large overarching principles they are reflected in the day-to-day decisions that agencies make. These kinds of decisions will have a tremendous impact on how an agency operates, what services it provides, and ultimately its financial results. That might be why Metro only recently implemented free transfers on its system, something that’s been part of (most) transit service in New York for close to two decades (adding to the economic health of the region by making transit easier).
The other distinction that drives some of the key financial outcomes for agencies is the kind of service(s) that they provide. Rail-only agencies or ones that focus primarily on rail are more likely to have higher farebox recoveries and stronger overall financial performance when compared to bus agencies that tend to provide more coverage, making sure that more people in the region have access to the public transportation network.
There is a famous line in politics that “geography is destiny”. While that may or may not be true, when it comes to public transit, the mission statement is destiny.