Adhering to an advertised bus schedule is vital in the public transit business. Did you ever wonder how a bus schedule is established in the first place? The scheduling of buses is both art and science. Here are a few examples of the factors that make bus scheduling more complex than you’d think.
Two primary issues in the scheduling process are the path the bus will travel and how often service is provided. For instance, the longer the route, the lower the frequency of service to each stop. Related to this, is the route-choice taken between the end points of a route. The more straightforward the routing, the quicker the bus travels between end points. However, this also means people have to walk farther to reach the bus stops. What we are talking about is balancing speed of bus travel, with access to bus stops, and street coverage. Most of the time, route scheduling requires a balancing of these competing three conveniences – all of which are important to the traveling public.
Providing easy access and direct service is easier when local streets are laid out in a grid pattern, like they are in San Francisco. Balancing these factors in an area full of cul-de-sacs, dead end streets, and non-grid patterns, which are typical in suburban areas, is much more challenging.
One way to overcome the non-grid street challenges and fully address all three conveniences is to put more buses and routes into service. However, that requires a financial investment of public resources well beyond what is available or realistic. Instead, we must pursue the art and science of balancing access, coverage, and directness.
Another factor considered when scheduling a bus is what we call trip generators, which is the reason why you take the bus, like a destination. Trip generators for County Connection service include BART stations, schools, libraries, shopping, restaurants, medical offices and hospitals, and other bus routes.
With respect to these trip generators, County Connection takes into consideration the timing of BART train and regional route connections and school bell times. County Connection policy calls for a goal for 95 percent of scheduled buses in the AM commute period to arrive at BART stations between three and 15 minutes prior to a train departure to San Francisco. Likewise, our goal is to have 90 percent of scheduled buses depart BART within three to 10 minutes of the arrival of a BART train. We also meet the school bell times of middle and high schools in our service area. Sometimes, meeting a school bell time means that we can’t meet a BART train arrival/departure that is further down a given bus route, for that particular trip.
In short, scheduling County Connection buses involves making choices between competing demands. Meeting a school bell time versus meeting a bus connection, or providing access versus directness of routing requires both art and science to be applied to bus scheduling. Add in the scarce resources we have available to deliver important transit service for the residents of central Contra Costa County, and you begin to see the delicate balances required.
I hope this sheds some light into our scheduling process. Next month, I’ll give you the inside scoop on a related topic, when I answer the question, “Hey, why is that bus empty?”