Creating synthetic baseline populations

To develop activity-based travel models using microsimulation, individual travelers and households must be considered. Methods for creating baseline synthetic populations of households and persons using 1990 census data are given. Summary tables from the Census Bureau STF-3A are used in conjunction with the Public Use Microdata Sample (PUMS), and Iterative Proportional Fitting (IPF) is applied to estimate the proportion of households in a block group or census tract with a desired combination of demographics. Households are generated by selection of households from the associated PUMS according to these proportions. The tables of demographic proportions which are exploited here to make household selections from the PUMS may be used in traditional modeling. The procedures are validated by creating pseudo census tracts from PUMS samples and considering the joint distribution of the size of households and the number of vehicles in the households. It is shown that the joint distributions created by these methods do not differ substantially from the true values. Additionally the effects of small changes in the procedure, such as imputation of additional demographics and adding partial counts to the constructed demographic tables are discussed in the paper.     

Assessing communicative rationality as a transportation planning paradigm

Communicative rationality offers a new paradigm for transportation planning. Drawing on the literature and lessons from transportation planning practice, this paper describes the characteristics of a “communicative” form of transportation planning and compares them with conventional practices. A communicative rationality paradigm would place language and discourse at the core of transportation planning. The paper argues that it would lead to greater attention to desired transportation ends (goals), better integration of means and ends, new forms of participation and learning, and enhanced deliberative capacity. The paper explains the implications of this paradigm for the role of the transportation planner, the purpose of planning, the planning process, communicative practices, problem framing, and the nature of planning analysis. The paper concludes with an assessment of communicative rationality's ability to promote more effective transportation planning. It seeks to create a dialogue that will support the investigation of new transportation planning processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Running for the 7:45: The effects of public transit improvements on commuter stress

This research project took advantage of the implementation of a major mass transit improvement by New Jersey Transit which provided a "one-seat ride" into New York City for many commuters who previously had to transfer in Hoboken in order to take Port Authority Trans Hudson (PATH) trains into New York City. The creation of this new service provided a natural experiment in which some riders switched to the new route, while others continued to use their previous route. We studied psychological and psychophysiological responses to these commuting options, using a quasi-experimental, pre-post change, field research design.We found that riders on this new line had lower levels of stress, as multiply measured, than they had earlier, before the advent of this new train, or than did other riders currently using the Hoboken-PATH option. The stress effects seemed to be mediated by the time of the trip – that is, the reduced trip time of the new, direct service seemed to be a primary factor in the reduced stress to riders. Predictability of the trip was also inversely correlated with stress, but did not distinguish between the commuter groups. These results were largely replicated with a student group who rode the same lines acting as simulated commuters.     

Parking subsidies and travel choices: Assessing the evidence

This article reviews empirical studies of how employer-paid parking affects employees' travel choices. A strong effect is found: parking subsidies greatly increase solo driving. When employers reduce or remove parking subsidies, a significant number of solo drivers shift to carpools and/or transit. This conclusion is based on studies of parking subsidies in a variety of circumstances, including central city and suburban areas, private and public employers, and clerical and professional employees. Three measures are developed to compare changes in commute patterns: changes in the share of solo drivers. changes in the number of autos driven to work per 100 employees, and the parking price elasticity of demand for solo driving. The studies reviewed here show that 19 to 81 percent fewer employees drive to work alone when they pay for their own parking. Because 90 percent of American commuters who drive to work receive employer-paid parking, these findings are significant for designing transportation policies to reduce air pollution, traffic congestion, and energy consumption.     

Rochdale remembered: a personal memoir

The Committee of Inquiry into British Shipping, chaired by Viscount Rochdale, reported in May 1970, over 25 years ago. It is therefore appropriate to consider how it come to be established, its working and the validity of its ideas. As economic adviser to the Committee. I attended almost all its meetings, though the Secretary, Donald Simpson, wrote most of the Report     

New appraisal values of travel time saving and reliability in Great Britain

Transportation - This paper provides an overview of the study ‘Provision of market research for value of time savings and reliability’ undertaken by the Arup/ITS Leeds/Accent consortium...     

Communication innovations,urban form and travel demand: Some hypotheses and a bibliography

Hypotheses are developed about the effects of telecommunication advances on urban growth patterns and urban travel demands. It is suggested that CBD (central business district) office employment might decentralize if telecommunications could effectively substitute for short inter-office business trips and that job decentralization would alter journey-to-work patterns and the viability of certain public transit systems. Major research questions are raised and keyed to an extensive bibliography.     

The net incidence of transit subsidies: a case study

The purpose of this paper is to investigate the net incidence of government subsidies to a transit system (i.e., the net impact of who pays and who benefits from transit subsidies). Rather than considering the U.S. transit subsidy program in the aggregate, the net incidence of subsidies to a particular transit system — Tidewater Regional Transit (TRT) — is analyzed. The paper concludes that the net incidence of the TRT subsidy program is progressive. Furthermore, the paper provides a methodology that can be used for investigating the net incidence of government subsidies to other transit systems.