Impact of proposed federal limits on US bagged food aid shipments: reduction in MSF carrier profits—a risk assessment 1

This paper is a stochastic risk simulation of the impact of proposed federal tonnage limits on US Maritime Security Fleet (MSF) bagged food aid shipments. Only MSF (i.e. federally subsidized carriers/vessels for war, or emergencies) and non-MSF US carriers (therefore, at competitive disadvantage) can compete for such shipments—representing an indirect subsidy to both groups. To compensate, US Congress proposed a financial penalty (loss of voyage subsidy) on MSF carriers for food aid above a certain limit. Accordingly, certain carriers will be policy 'winners' (non-MSF—larger food aid shipments), and others 'losers' (MSF). By simulating loss-minimizing economic behaviour by MSF carriers—using five stochastic factors—I obtain losses substantially below those claimed by the MSF owners.

Simulated annual-average MSF profits reduction is $3.5 million—within a large confidence interval; if no carriers surrender their subsidies (as claimed by MSF owners), a reduction of $6.0 million. Only 16% of annual MSF voyages are affected by a 2,500-ton limit (3%; 5,000-ton limit). Minimizing losses, 25 (of 41 affected) annual MSF voyages replace 38,000 tons of food aid with 23,000 tons of other cargo—forgoing $2.1 million in yearly direct subsidies. Two assumptions explain most of this simulated loss reduction.     

Impact of interviewing by proxy in travel survey conducted by telephone

Telephone‐interview surveys are a very efficient way of conducting large‐scale travel surveys. Recent advancements in computer technology have made it possible to improve upon the quality of data collected by telephone surveys through computerization of the entire sample‐control process, and through the direct recording of the collected data into a computer. Notwithstanding these technological advancements, potential sources of bias still exist, including the reliance on an adult member of the household to report the travel information of other household members. Travel data collected in a recent telephone interview survey in the Toronto region is used to examine this issue. The statistical tool used in the research was the Analysis of Variance (ANOVA) technique as implemented within the general linear model framework in SAS. The study‐results indicate that reliance on informants to provide travel information for non‐informant members of their respective households led to the underreporting of some categories of trips. These underreported trip categories were primarily segments of home‐based discretionary trips, and non home‐based trips. Since these latter two categories of trips are made primarily outside the morning peak period, estimated factors to adjust for their underreporting were time‐period sensitive. Further, the number of vehicles available to the household, gender, and driver license status respectively were also found to be strongly associated with the underreporting of trips and thus were important considerations in the determination of adjustment factors. Work and school trips were found not to be underreported, a not surprising result giving the almost daily repetitiveness of trips made for these purposes and hence the ability of the informant to provide relatively more precise information on them.     

Active Suspension Control to Improve Vehicle Ride and Handling

In practice most active vehicle suspension work can be traced to two sources, Lotus' modal control and Karnopp's skyhook damper. A model is developed which allows comparison of different active suspension control algorithms. The Lotus modal control algorithm is reviewed, and compared with Karnopp's skyhook damper. It is shown that a tight inner closed loop allows the Lotus algorithm to achieve the inertial damping described by Kamopp for a single comer or quarter car. It is suggested that to achieve simultaneously high inertial damping and good disturbance rejection an inner force loop is desirable. A vehicle control scheme is presented which combines the Lotus modal decomposition with Karnopp's skyhook damper, allowing nearly optimal ride and simultaneously permitting modification of vehicle handling properties.     

Paratransit — Existing issues and future directions

Paratransit services bridge the gap between static fixed route transit and the flexible automobile travel. Paratransit services provide personalized public trapsportation by responding to the needs of individual markets and users. Unfortunately, fragmentation of the paratransit sector and institutional and regulatory constraints have prevented or complicated realization of paratransit's full potential. The orientation in this paper is not primarily to identify promising paratransit applications. Rather, it is to examine basic characteristics of paratransit services, fundamental issues unique to paratransit, existing problems that are constraining paratransit development, and ways to overcome or minimize existing difficulties. A taxonomy of paratransit services is proposed so that these systems can be better related to each other. The institutional environment of paratransit is examined from the viewpoints of planning, operations and regulation. A primary focus is on integration of various paratransit services and of paratransit and conventional fixed route services. Several proposals are made relating to improvements in existing services, new service concepts, new institutional arrangements and service integration.     

Consumers as participants in transportation planning

Legal requirements for public participation in transportation planning increase the opportunity for transportation consumers to influence the design of systems they will use. However, the implementation of these requirements may also increase the possibility that system design will be dominated by the opinions of outspoken groups. This study postulates that public participation is biased, and seeks to test this proposition using data from an Oregon survey consisting of approximately 2,400 respondents. Using Automatic Interaction Detector and cross tabulation analyses, different participation rates were uncovered for groups identified by demographic, attitudinal and behavioral variables.The authors thank the Oregon Department of Transportation for making the original data for the study available.     

Understanding the Relationship Between Physical and Virtual Representations of Transit Agencies

Abstract

This study examines whether physical attributes of transit agencies, such as agency size, make a difference in how transit websites are designed, and how transit information is distributed. The objective of this study is to see if there is a relationship between physical and virtual representations of transit agencies. A rating instrument is developed for evaluating the quality of transit websites. Our findings suggest that transit agency size plays a key role in determining website quality: When the size of transit system is large, the information about the agency is too complex to be effectively presented on web pages. Thus, the quality of the large agencies’ websites is lower than medium-sized agencies. Instead, we find that large agencies attempt to design more user-friendly sites, and provide advanced information searching tools to compensate for low information quality. Policy implications for transit agencies are discussed.     

Forecasting Travel Demand with Alternatively Structured Models of Trip Frequency

Abstract

This paper develops alternatively structured trip frequency/generation models, and investigates their forecast performance. The first model presented is the simple linear model with a discussion of its theoretical shortcomings. Models that address, in a progressive fashion, the underlying shortcomings of the linear model are then presented. These models are namely the truncated normal model, the Poisson model, the negative binomial model, and an ordered logit model. The modeling unit employed in the study is the individual. The models are assessed by how closely they are able to replicate trips produced by each individual in the dataset, and by each traffic zone. This assessment of performance in prediction is conducted on an estimation dataset collected in the Toronto Region in 1986, and on an independent dataset collected in the same geographic region, 10 years later, in 1996. The results show that, notwithstanding the simplicity of the simple linear model and its lack of an explicit underlying travel behavioral theory, it predicts travel in the base and forecast years with less error compared to any of the more complex models.     

The economic impact of commercial fisheries and marine‐related activities: A critical review of northeastern input‐output studies

Abstract

The application of the input‐output method to regional analysis of coastal zone production and consumption activities is examined. A review of previous Northeastern input‐output studies provides a framework for analyzing selected methodological procedures utilized in this type of analysis. While commercial fishing and other marine‐related activities have been shown to have important economic impact on coastal communities, the review indicates that in certain cases the methodological procedures adopted tended to yield an upward bias to the estimation of economic impacts. Standardization of procedures is recommended for future studies.     

Port competitiveness in container traffic from an internal point of view: the experience of the Port of Algeciras Bay

The objective of this article is to analyse the factors that affect port competitiveness from the perspective of the agents and companies that operate in one of the Mediterranean ports most active in container traffic: the Port of Algeciras Bay (PAB). It is essential to understand the perspective of the suppliers of port services, in order to apply the necessary judgment when formulating policies to strengthen the competitive position of a port. The model selected to meet the objective outlined is based on the ‘extended diamond’ of Porter. The universe for the study comprises all the institutions and companies involved in the containerization process in the Port of Algeciras Bay. Within this methodology, two procedures are utilised. First, from the quantitative perspective, a survey has been conducted to obtain responses to two groups of questions, one dealing with situation and the other with perceptions. Second, and from a qualitative perspective, several open interviews have been conducted to corroborate the responses obtained to the questionnaire. From the data obtained in the survey, a model has been estimated that minimises the sum of the residuals in absolute value, utilizing the L1 regression; this model enables the competitive advantages and disadvantages of the PAB, from the point of view of the port operators, to be determined by an analysis of residuals. This analysis demonstrates that the variables representing greater competitive advantages are associated with trans-shipment, and with the maritime accessibility of the Port to vessels, whereas those generating greater disadvantages are associated with rail transport (which, according to those surveyed, has resulted in the diversion of significant volumes of traffic to other Spanish or European ports with better communications, particularly Valencia, Barcelona and Gioia-Tauro, and with the state of competition in container trans-shipment activities.