PlanItMetro

Correlation between weekday Metrorail (monthly total) ridership and the number of jobs in the District of Columbia, FY05 – FY12. Note the “natural log” (ln) of each is illustrated.  The low-ridership outlier is due to Snowmageddon, February 2010.

Demand for public transportation services is not a direct demand, meaning that transit is a means to another end:  a traveler on transit rarely takes transit for the sake of travel but because they have a need for work, shopping, entertainment, etc.  Additionally, many factors determine whether a traveler’s demand for a good or service translates into a public transportation trip or a trip by a private automobile.  Therefore, transit demand is driven by two different sets of factors, the first being the changing demand for goods or services that result in the demand for transportation and the second being the factors that influence which transportation mode is chosen.

For example, having a job creates the need to travel to work.  Yet other factors — such as the levels of transit service between home and work locations, the price of gas, the transit fare, the relative travel time between car and transit, and car-ownership rates – may have some influence over whether the demand for travel translates into the demand for a travel trip. Read more…