Task Order 5408
Transit Operations Research


Improving Mobility through Enhanced Transit Services

Michael Cassidy
Civil and Environmental Engineering
University of California, Berkeley

Summary

Demand for public transport service varies over time and geographic regions, and low demand density usually means high-operating costs per customer served. Devoid of innovative solutions, the mobility needs of customers in low-density regions and/or during periods of low demand density are often under-served. This is especially true today when public transit is highly subsidized and must carefully monitor the cost effectiveness of its operations.

The objective of this research is to investigate the viability of using transit-taxi in small-to-medium sized U.S. cities with established fixed-route bus service but during hours when the demand density is low and bus service is not operational, e.g. from 9pm to 6am, and on weekends.

Transit-taxi is characterized by:
  1. use of existing transit stop/station infrastructure as "origins" and "destinations" by smaller vehicles;
  2. being in use when regular buses are not operational;
  3. being available to everyone; and
  4. shared ride experience.
Sometimes there is also an option for passengers to call in advance for a pickup.

Motivated by successful use of transit-taxi in some international communities, we study in this research how the transit-taxi concept can be adopted by U.S. cities. We will identify the physical and social-economical characteristics of a community that can make transit-taxi an economically viable solution to the problem of reduced mobility during after-hours. We will also examine institutional barriers that prevent many transit agencies from implementing innovative solutions. And for our pilot test site we will devise an implementation plan that combines efficient operations with innovative institutional arrangements.

The successful adoption of the transit-taxi concept would foster a safer travel environment, lower travel times for transit customers, enhance reliability and connectivity, and could lead to increased transit ridership. Our research findings will help cities identify services that are appropriate for their community characteristics and devise action plans to meet their mobility needs.

Methodology

The study team will use an integrated systems approach to investigate the transit-taxi concept from the following two perspectives: operational and policy/institutional. Each of these perspectives is critical in understanding the issues that are likely to arise as one progresses from concept to implementation.

We will combine the gathering of empirical evidence and data and the mathematical modeling of transit systems to develop the transit-taxi concept and further our understanding of its critical issues. Based on this understanding, we will identify a pilot test site for the transit-taxi service, and work with the local community to develop a detailed plan for a field operations test.

To develop the transit-taxi concept, we will begin with a comprehensive review of the literature on international and domestic transit practices in low demand-density scenarios. The literature review will be supplemented with preliminary surveys of organizations/agencies involved in transit-taxi programs. We will examine characteristics of the service areas (such as size, population density, demographics, social-economic activity patterns etc.) as well as characteristics of the service providers (such as labor contract provisions, size and age of agency, fleet size, peak-to-base ratios, and other performance measures). From this we will assemble a panel of likely scenarios under which transit taxis may work, obstacles to implementation, and applicability of international programs to U.S. operating environment.

We will next develop a quantitative understanding of the impacts of important factors, such as passenger demand patterns and cost-structures of the transit operators, on the economical viability of transit-taxi service. To this end, we will build mathematical models of transit services, develop operating strategies and derive near-optimal parameters such as stop spacing and service frequency for transit-taxi service under typical demand scenarios. Model outputs will be compared with alternative mobility solutions; this will yield insights on conditions under which transit-taxis are the most cost-effective service to provide.

By going through public records, communicating with transit agencies, and making site visits, we will finalize a pilot test site based on all the above considerations.

We will next develop a program design for the pilot test, laying out details of how this particular pilot program should take place. An important institutional difference between transit services in the U.S. and in other countries is the existence of the American Disabilities Act, which mandates that any fixed route transit service for the general public must be complemented by a door-to-door service for the disabled in the same service region. Therefore, one possible design is a hybrid type of transit-taxi service that incorporates some elements of demand-responsive door-to-door service. In this hybrid mode of operation, paratransit minibuses operate on fixed routes and at scheduled frequencies, but people living close to the routes can request pickup within a short notice. This type of scheme serves the functions of both a fixed-route and a paratransit service, so the extra cost for ADA conformation may be nearly eliminated. Based on the finalized design, we will develop a proposal to implement the pilot program, with emphasis on overall system architecture, ITS technologies used, and system operation.