An econometric model of vehicle use in the household sector

Vehicle-use modelling at the household level has taken on new importance with the pressures on governments to encourage more efficient utilisation of increasingly scarce nonreplenishible liquid fuels. The fundamental energy equation recognizes two direct influences on consumption—the fuel efficiency of the vehicle and the amount of use. Until recently, the interrelationship between vehicle choice and vehicle utilisation at the household level was acknowledged but ignored. The availability of reliable vehicle-use data at the household level now enables a more serious effort at amending the imbalance of research effort where the reliance has been predominantly on vehicle choice modelling and gross (exogenous) assumptions on utilisation as a basis for predicting fuel consumption. This paper proposes an econometric method for identifying the influences on household vehicle use. It differs from previous empirical work in that vehicle kilometers, fuel cost per kilometer and vehicle fuel efficiency are endogenous, with utilisation of each vehicle endogeneously dependent on the utilisation of each and every household vehicle. The data are drawn from wave 1 of a four-wave panel of 1436 households in the Sydney metropolitan area. The empirical findings expose a set of influences on use hitherto not considered. The model specification provides an appropriate module for integration with household-based discrete choice models of vehicle choice.     

Evaluation of truck configurations based on structural performance of bridges

Contained herein are the results of research which quantifies the effects that various existing and projected truck configurations have as live loadings upon bridges which currently exist on the National Bridge Inventory (NBI). The truck configurations were determined from those actual or proposed vehicles which exhibit the highest GVW and which either are causing or are perceived to cause the highest levels of overstress on bridge superstructure elements. In order to simulate most accurately the actual field conditions, a criterion was defined which contained three major requirements: 1) The bridges utilized within the study shall be defined as being a statistically significant sample and be actual bridges taken from the NBI; 2) The analysis method shall be consistent with those actually used by engineers in designing and rating bridges, and; 3) The criteria utilized in evaluating the various bridge structures under the defined loadings shall be consistent with current practices. The results obtained indicates the acceptability of various truck configurations by GVW, size, and axle deployments, by system for the different criteria now in use.     

Uncertainty in the context of highway appraisal

Transport planning is based on traffic forecasts which are subject to great uncertainties. These uncertainties have generally been ignored or, at least, not explicitly included in the planning process. This paper describes the principles behind the estimation of the uncertainty (or range of error) of the forecasts of a traffic model and discusses the means by which this information can be absorbed into the decision-making in transport planning projects. These principles have been applied to the appraisal of a British highway project and throughout the paper reference is made to this project in order to illustrate the results of the practical application of an explicit treatment of uncertainty. It is believed that this approach can and should be developed for application in most areas of transport planning, leading inevitably to an improvement in the quality of the decisions taken.     

The EEZ and the progress of fisheries negotiations January to May 1977

This paper discusses negotiations, relative to sea fisheries, in terms of international arrangements—arrangements between the European Economic Community (EEC) and Third Countries; and those between member states of the EEC.     

The application of cost-benefit analysis to transport investment projects in Britain

This paper explains the need for the application of cost-benefit analysis to the evaluation of alternative projects for investment in the transport field and outlines briefly the historical development of the technique. The results of a comparative survey of a number of cost-benefit studies which have been carried out in Britain and some conclusions as to their thoroughness and comprehensiveness (or otherwise) are presented. The article concludes with a number of specific and detailed recommendations to remedy apparent methodological weaknesses. Six of these recommendations seem to merit particular attention:

1. The viewpoint of most studies should be extended so as to avoid confinement, for example, within an arbitrary local government boundary, and a wider range of “externalities” should be considered. Intangibles should be included explicitly in all such evaluation exercises.
2. The actual incidence of costs and benefits should be examined in order to indicate the directional impact of the project and its implications in terms of equity. The elimination of transfer payments and double-counting should be postponed until the latest possible stage in the evaluation.
3. Equity considerations should be investigated in any transportation plan, since most projects have considerable equity implications for particular areas or socio-economic groups.
4. Discounted cash flow techniques, which are still used only in a minority of transportation studies, should become standard practice. Most evaluations are based on a single-year rate of return, or at best on simple trend forecasting. More resources should be devoted to proper evaluation of alternative plans which give due importance to the cost and benefit streams through time.
5. Sensitivity analysis should be used in all transportation evaluations. Knowledge of the impact of different assignments, shadow prices, and discount rates are essential information for any decisionmaker.
6. Last, but not least, much greater communication should exist between analyst and decisionmaker than has existed in the past.