What are the Drivers for Demand of Transit Services?

February 5th, 2013

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.

Over the past several years, Metro has worked to determine which factors influence public transportation demand in the long term.  We have some confidence that regional transit demand is highly correlated with a variety of factors, including:

  • Regional economic indicators: jobs and population of the District or the region
  • Tourist activity:  months with high levels of tourist activity generally have higher ridership
  • Seasonality: Lower ridership in months where vacations and holidays are common
  • Direct costs:  Transit fares impact off-peak and weekend ridership, and gas priced above $4 per gallon appears to increase demand for transit in general
  • Weather: extreme weather generally has a negative influence on ridership demand, including snow, rain, heat and cold
  • Special events: presidential inaugurations, rallies, national celebrations and protests can have a noticeable impact on monthly ridership and revenue totals

These factors and more are evaluated for about 18 months into the future in order to generate estimates of future ridership and revenue for the development of Metro’s budget ever year.

What factors influence your travel demand, and whether you take Metrorail, Metrobus or another transit mode?

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  1. David
    February 5th, 2013 at 17:41 | #1

    My key factors:

    Cost: When choosing a place to live, I evaluate the cost of transportation to my school or workplace as a component of my total cost of living. Metro can be cost competitive, but at my previous residence it was not much cheaper than driving. For someone who still maintains a car for other reasons, the marginal cost of driving to commute is not much higher than commuting by Metro. For real savings, one would have to get rid of the car altogether.

    Network size/scope: Can I get where I want to go on Metro? Without riding more than 2 lines, if possible, or navigating an unfamiliar bus route?

    Time: How much faster or slower is it to ride Metro, and what is the cost tradeoff? If I am working nonstandard hours it may be faster just to drive, so my work schedule is going to be important. Working late also means long intervals between trains, which can easily add 20-30 mins to a commute.

    Also very important to me, but harder to quantify, is service quality. In the long run, this will determine whether I plan to commute by Metro or car, given that I have the option. Some aspects of it are easily measurable: average on time performance, number of breakdowns, etc. Those are critical, but they’re only a baseline.

    Something that doesn’t get measured is how many times I step off the train feeling physically ill from motion sickness because the driver alternates between a lead foot and riding the brakes. That factor alone is enough to undercut all the things the system does right. I won’t stop riding tomorrow because of it, but it will be a consideration when the time comes for me to rethink my living and transit arrangements.

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