Evolving Strategies for Demand Responsive Transit


For people who are unable to drive or use conventional transit (e.g., fixed route buses and trains), getting around can be a real challenge. One group is receiving increasing attention in the transportation community: people with physical or mental disabilities that prevent them from being able to use existing buses and trains. The Americans with Disabilities Act of 1990 (ADA) requires transit agencies to operate curb-to-curb paratransit with ¾ mile of fixed route bus services for these. Although ADA paratransit constitutes only 1% of transit trips in U.S., the services make up 8% of the operating costs. Furthermore, demand for ADA paratransit increased by 41% from 2000 to 2010, and the trend of increasing demand and increasing cost is expected to continue as the American population gets older [1]. This presents a major challenge for transit agencies: equitable service must be provided for customers with disabilities, but increasing costs threaten the ability of agencies to continue providing adequate ADA paratransit along with conventional services. Recent and ongoing research at UMass Amherst addresses multiple strategies for managing ADA paratransit needs.

One way to approach the problem of mounting paratransit costs is to focus on optimizing the operations. Recent studies of ADA paratransit demand and operation patterns in New Jersey have shown that the total operating cost in a service region can be modeled based on the area of the region, the rate that trips are requested per time, and the allowable time window for an on-time pick-up [2].  There are ways to geographically align service regions to cover large areas in order to minimize the negative effects of making customers transfer.  It can be beneficial to break up large regions into zones such that one zone provides service within a dense urban core, and another zone provides service to more distributed areas [3].

Another approach to the problem is to manage demand by incentivizing users to travel at times of day when there is excess system capacity. The current ADA regulation requires agencies to schedule paratransit service within one hour of the customer’s requested pick-up time and to charge no more than 1.5 times the fare of conventional transit service. Peaks in demand at certain times of day leave agencies with no choice but to purchase more vehicles and hire more drivers, but these resources are costly when they go unused at other times of day. A time-varying fare, within the ADA constraints, could incentivize users with flexible schedules to travel at less costly times of the day to improve the system’s overall efficiency [4].

An emerging question is what role existing ADA paratransit should play in serving this population in the long term. We know that shared-ride services are most efficient in areas with dense demand.  In the suburban fringe, there are many trips that could be served more cost-effectively by taxis or on-demand mobility services (e.g., Uber, Lyft). In the Boston area, where the average cost of serving a one-way paratransit trip is $46.88, the MBTA is piloting a program to subsidize taxi trips for some users [5]. Despite concerns about vehicles being physically equipped and drivers having appropriate training to serve customers with disabilities, demand responsive services that allow vehicles to be shared by multiple user groups hold great promise for bringing down the cost of providing high-quality ADA paratransit service. Perhaps the changes that emerging technologies are bringing for mobility services will be a great equalizer that can afford the same transportation choices to people with disabilities as the rest of the general public. One thing is certain, the future users are going to require flexible and efficient transportation systems to meet their diverse needs.

By: Dr. Eric Gonzales

  1. American Public Transit Association (APTA) (2012). 2012 Public Transportation Factbook. Available online from: http://www.apta.com/resources/statistics/Documents/FactBook/
  2. Rahimi, M., Amirgholy, M., Gonzales, E.J. (2014). Continuum approximation modeling of ADA paratransit operations in New Jersey. Paper Number 14-4864. Transportation Research Board 93rd Annual Meeting, 12–16 January, Washington, D.C.
  3. Rahimi, M., Gonzales, E.J. (2015). Systematic evaluation of zoning strategies for demand responsive transit. Paper Number 15-4023. Transportation Research Board 94th Annual Meeting, 11–15 January, Washington, D.C.
  4. Amirgholy, M., Gonzales, E.J. (2015). Demand responsive transit systems with time dependent demand: User equilibrium, system optimum, and management strategy. Transportation Research Part B, doi:10.2016/j.trb.2015.11.006.
  5. Massachusetts Bay Transportation Authority (MBTA). Riding the T. Available online from: http://www.mbta.com/riding_the_t/accessible_services/?id=7108

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