Julian Benjamin

The effect of policy and background variables on total factor productivity for public transit

This paper investigates total factor productivity as a unified measure of transit performance. The approach uses the shift in the cost function of inputs and outputs as the measure of change in productivity. A three step regression procedure was used to estimate model parameters. The approach was applied to a sample of transit agencies. Predictor variables were tested for a two-year period representing different financial and background situations. Hypotheses were tested for static and dynamic measures of environment and policy with capacity and efficiency and for measures of capacity and efficiency with productivity. It was found that when vehicle-miles was the output measure, only vehicle efficiency was related to labor productivity. Further, it was found that when passenger-miles was the output variable, only population and fleet size were good predictors of total factor productivity. Productivity is, in general, stable and approximately constant for these agencies. The implication for transit agencies is to concentrate efforts to improve productivity on highly congested corridors and, overall, through the use of vehicle and manpower scheduling.

An analysis of mode choice for shippers in a constrained network with applications to just-in-time inventory

The process of choosing a mode of transport for the distribution of materials by a shipper is analyzed in terms of setup, inventory, and order costs as well as the usual cost of hauling. Capacity and requirements constraints are also considered. The procedure is further extended to include transshipment warehouses and concave transport costs. The problem is formulated as a nonlinear program and local optimal solutions are found for each problem using GINO, a generalized reduced gradient algorithm. The nonlinear programs are also solved using a decomposition procedure. It is found that the choice of mode has implications for shipping patterns throughout the network. In particular, adoption of special shipping strategies, such as the just-in-time (JIT) inventory policy, depend on the comparative total costs for each link in the network. When the shipping strategy is JIT, the cost of production at the demand point must also be considered. It is suggested that total cost of shipping, storage, and production be the decision criterion wherever shipping options are available and that costs for an entire network be considered when transport decisions are made.

IMPACT OF ADVANCED PUBLIC TRANSPORTATION SYSTEMS ON TRAVEL BY DIAL-A-RIDE

The degree to which Advanced Public Transportation Systems (APTS) are expected to increase ridership is studied. The responses from a survey of Dial-a-Ride users to estimate the parameters of statistical models of user behavior were used. The respondents were asked to rank hypothetical scenarios in which level of service was varied. Level-of-service attributes included, among other variables, changes in travel time and ability to reserve the trip in advance. The respondents were asked to state how many trips they would have made during the past week of travel, given the hypothetical service attributes described in the question. The models developed link the average number of trips per week using Dial-a-Ride and the level of service offered by the Dial-a-Ride system. The modeling framework attempts to resolve the bias issues inherent in the use of stated preferences (SP) data, where respondents are asked to answer questions about a hypothetical situation. A basic methodology of combining revealed preferences and SP data is provided to evaluate the effect of different APTS configurations on ridership.

A STRUCTURAL EQUATIONS ANALYSIS OF REVEALED AND STATED TRAVEL MODE AND ACTIVITY CHOICES

This study extends the structural equations model to incorporate both revealed and stated preference data to analyze activity-based travel behavior. The model is applied to examine the relationship between activities and mode choice on the data from the first wave of the panel study conducted for the Puget Sound Regional Council. It is found that the attitude toward comfort of travel, car requirement for job, and travel time are significant predictors for the mode choice decision. Comparing alternative decision processes, the data support that the mode choice and activity choice decisions are affected by unobserved common factors, and the mode choice and the activity choice decisions are made independently. There is some evidence that the stated-preference model has the same model structure as the revealed-preference model, and the stated-preference data help improve the fit of the entire model.

Forecasting Paratransit Ridership Using Discrete Choice Models with Explicit Consideration of Availability

In most developed countries, the population of the elderly and disabled is growing rapidly. These individuals require transportation service suited to their needs. Such service may be provided by applying emerging technologies to dial-a-ride transit. This research develops a methodology to quantitatively evaluate the impact of paratransit services on a traveler’s mode choice behavior. The mode choice model explicitly considers availability of alternative modes and includes latent factors to account for taste heterogeneity. Stated preferences are also used to elicit preferences for new paratransit services. The methodology is empirically tested with data collected in Winston-Salem, North Carolina. The model system developed is applied to evaluate the effect of improving service attributes and the impact of the introduction of new cost-effective modes on modal shares. Results of the policy analysis indicate that (a) transit policy changes, such as fare reduction, would have little effect on automobile driver and automobile passenger shares; (b) an improved reservation system for dial-a-ride services would produce shifts in mode share; (c) the proposed new bus deviation service was favored; (d) free bus service reduces dial-a-ride share; and (e) an increase in awareness of a dial-a-ride system would significantly increase its share.

A Study of the Impact of APTS on Service Quality Perceptions of Elderly and Disabled Riders

New transportation technology that directly impacts consumers should be evaluated by the people who are affected. This article summarizes a study analyzing consumer response to an automated dispatching program called Mobility Manager at a demonstration site in Winston-Salem, North Carolina. Mobility Manager was applied to the TransAID demand-responsive mini-bus service for elderly or disabled riders. Survey data from two questionnaires, before and after the implementation of Mobility Manager for the same subjects, were used to examine travel behavior and perceived service quality. These travelers reported improved telephone access and shorter travel times. The respondents’ travel patterns after implementation remained stable. This article also provides econometric estimates of the change in the number of trips as a function of the change in travel attributes affected by the implementation. Changes in the number of trips were treated as a Poisson random variable. Results from a Poisson regression show that the primary beneficiaries were riders with disabilities. Perceived service attributes that significantly affected changes in trips were length of trip, number of stops to pick up additional passengers, and physical comfort.

Total factor productivity in transit systems: 1983–1988

Performance in single mode bus transit systems is analyzed in this paper. The paper points to two potential problems in using partial productivity and other measures in assessing the performance levels of transit systems. One solution suggested is total factor productivity which is shown to be mathematically related to many of the traditional measures of performance. Next, total factor productivity is determined using data for a sample of single mode bus transit systems. As part of the analysis, a neoclassical cost function is developed which allows for decomposition of total factor productivity among technical change and economies of scale. The major conclusions include growth of total factor productivity of 1.1% per year and technical growth of 1.14% per year. Growth of total factor productivity is attributed to output, the productivities of all inputs and technical change. Policy implications of these findings are examined.

A psychometric analysis of residential location

Abstract Traditional housing needs studies focus on the trade-off between location and housing amenities. In most models, mode choice is viewed as conditional behavior in a given setting. New movers, however, select a new environment which includes a house, neighbourhood and transportation system. By using psychometric techniques, the attitudes and preferences of new movers to the suburbs of a large northeast city were analyzed to determine the relative importance in their selection process of the transportation characteristics of the new location. It was found that local and regional transportation and public transit played little role in selecting an apartment. There was no evidence of tradeoffs between travel time and living space postulated by urban economics. Most important to the choice process of these residents were internal characteristics of the apartment and pricing issues. This supports the idea that suburbanites chose to be captive auto users even when equivalent housing opportunities with transport alternatives are available. Implications for public transit and land use planning alternatives for the suburbs are discussed.

RACE AND SEAT BELTS IN NORTH CAROLINA

An analysis of the determinants of seat-belt use for automobile drivers in the state of North Carolina is presented. A factor analysis and random utility model capture the attributes of seat-belt use that plausibly govern the choice of whether to use them. The principal findings are that enforcement measures such as the levying of fines for not wearing a seat belt are effective in encouraging seat-belt use and that racial differences play a role in the response to enforcement measures in that black drivers are more sensitive to seat-belt enforcement measures than other drivers.

Analysis of Feeling of Security on Public Transit Among Residents of Small Urban Area

Magnitude estimation for assessing personal security is introduced. Magnitude estimates were obtained and used to compute security indexes. The advantage of magnitude estimate-based indexes over summated scales is that they are ratio rather than ordinal data. Residents of Greensboro, North Carolina, were surveyed regarding crime in the vicinity of bus stops. Responses were analyzed, and violent crime around bus areas was rated 2.5 times more serious than nonviolent crime (e.g., panhandling). In a model of the index, the gender of residents, an interaction term denoting crime victimization and taking precautionary measures, and the crime rate were significant predictors; race and age were not.