RIDERSHIP ESTIMATION FOR A SUBURBAN PRT SYSTEM

The Chicago Regional Transportation Authority is evaluating the potential of Personal Rapid Transit (PRT) systems to meet the unique mobility needs of suburban centers. An important part of this evaluation is to determine the potential ridership, given travel patterns and mode preferences in Chicago suburban communities. This paper describes the approach used and the initial ridership estimates for candidate PRT demonstration systems in four such communities. The PRT system designs being analyzed as potential demonstration projects in the Chicago area are approximately 2.5 miles in length, serving primarily the major commercial activity centers in the community. Virtually all trips on the systems would be short, non-home-based trips. Examples would include trips between commuter rail or bus stations and workplaces, trips between office buildings and mid-day trips from office buildings to retail centers. These types of trips are not detailed sufficiently in conventional urban transportation models to provide the level of information needed to evaluate tyis type of PRT system. A market area analysis was conducted for the four major activity centers to determine the numbers and types of trips that would be candidates for PRT service. Intercept travel surveys were conducted to determine the existing trip-making patterns within these centers. To estimate the number of trips that would be candidates for the PRT service, a detailed inventory was conducted of existing land uses and of the types of access that could be provided between those land uses and potential PRT stations. A self-administered, computer-based survey instrument was used to determine the conditions under which individuals would use PRT for current and possible future travel activities. The survey computers collected information on the respondents' current mode choice, described the PRT system using a digitized slide show, and presented a set of future travel scenarios adapted to the respondents' current trip. Data from the survey were used to estimate multinomial logit-form mode choice models for both work and non-work trips. The study found a significant range among the activity centers analyzed both in the number of trips that would be servced by PRT and in the sensitivity of PRT ridership to fare. Non-work uses were found to be particularly cost-sensitive. PRT ridership estimates for the potential demonstration systems ranged from 8,000 trips/day for two of the activity centers to less than 2,000 trips/day for the other two areas.