Replacement, obsolescence and modifications of ships

A theory of replacement in the context of ocean going vessels is discussed. The approach is based upon costs rather than profits, and while there appear to be many difficulties in applying replacement theory to ships it is shown that there are some segments where the theory can still usefully be applied. The effect on replacement resulting from varying important cost parameters is shown and it is found that while fiscal measures have very little effect, capital cost and operating cost profiles have the most important influence. It is concluded that shipowners need to keep themselves fully informed of changes in cost and improvements in technology that may indicate replacement of a vessel somewhat sooner than normal replacement age.     

Effect of time-value distributions on transit headway optimizations

The issue considered is whether the biases that result from assuming a single value of waiting time in variable-demand headway optimizations (and the demand models on which they are based) can have a significant impact on the results of the optimization. Marginal benefit functions based on binary probit demand models, and incorporating the alternative assumptions of either a single value of time, a discrete distribution of time values, or a continuous distribution of time values, are derived and compared for several cases. These comparisons indicate the possibility of significant errors in several cases, the most realistic of which is that of a highly heterogeneous market composed of a large segment of “choice riders” and a smaller segment of “transit captives”.     

Coordination of urban transit services: The german model

In Germany, the need for coordination and integration of transport services has been seen as a pre-condition to improving public transportation. A major step in this direction,which attracted world-wide attention, has been the institution of the Transport Federation (Verkehrs verbund). The paper discusses the operation of the Hamburg Transit Federation and considers a number of factors which have created a favorable climate for the development of public transportation in Germany.     

A simultaneous route-level transit patronage model: demand,supply, and inter-route relationship

In this paper we present a route-level patronage model that incorporates transit demand, supply and inter-route effects in a simultaneous system. The model is estimated at the route-segment level by time of day and direction. The results show strong simultaneity among transit demand, supply and competing routes. Transit ridership is affected by the level of service, which in turn is determined by current demand and ridership in the previous year. The model demonstrates that a service improvement has a twofold impact on ridership; it increases ridership on the route with service changes, but it also reduces the ridership on competing routes so that the net ridership change is small. The model is thus useful for both system-level analysis and route-level service planning.     

Liner freight rates, discrimination and cross-subsidization

This paper reviews some of the current literature concerning liner freight rates. While upholding the traditional basis for the establishment of freight rate structures it disputes some of the arguments that discrimination or differential pricing policies lead to cross-subsidization of low rated by higher rated cargoes.     

Ranking of regional road investment in Norway

This paper explores the priorities for road investments in Norway, with particular emphasis on the use of benefit-cost calculus. The author tests whether the observed rankings of the Ranking Road Agencies are explained and/or influenced positively by the benefit-cost ratio. Second, based on a questionnaire survey, the tradeoff made by Regional Road Authorities between an economic welfare maximizing strategy and the observed strategy in analysed. Benefit-cost ratio is found to be a significant explanatory variable in only four out of fifteen regions. In only one region does benefit cost ratio explain more than 30 percent of the observed variation. The trade-off analysis demonstrates that ranking by benefit-cost ratio if adopted gives formidable return as compared to the observed rankings. The reasons given by the Regional Road Agencies for not ranking investment projects according to benefit cost ratio is that several important impacts are not valued monetarily and therefore are not included in the benefit-cost-ratio. The results of the questionnaire survey give reasons to doubt the Regional Road Agencies understanding of the welfare maximizing principles of benefit cost calculus. Concluding remarks on the observed behaviour of the Regional Road Agencies are also offered.     

The Elasticity of Supply of Transport

The tramp shipping markets are generally considered to operate under conditions approaching the textbook model of perfect competition. It is from this basis that an attempt is made to establish the marginal cost of a bulk carrier and thence the aggregate supply curve and elasticity of supply in respect of vessels operating in a given sub-market. As is generally known, when many vessels are laid up the supply tends to be very elastic and when vessels' output is severely strained, the supply is almost totally inelastic. What is perhaps not always appreciated is that between the two extreams the supply is elastic and virtually constant with a value in the region of 0.5.     

Strategic flexibility in shipping: an examination of a sector of the short‐sea ferry market

In the generally more dynamic modern business environment new modes of strategic planning have emerged, in which a premium is attached to the maintenance of flexibility in resource deployment. This paper discusses the principles involved, and considers the capacity of a segment of the sea ferry industry to exploit strategic flexibility as a means of coping with a rapidly changing environment. Potential sources of flexibility are examined in the paper and possible constraints identified. For the sector in question, it appears that strategic flexibility has been unduly limited by the nature of the resources employed, by prevailing corporate values, and by a tendency to respond to environmental uncertainty by short‐term reactions rather than long‐term measures. The general conclusion of the paper is that the sector examined, and possibly the industry as a whole, is strategically weak.     

Velocity and normal tyre force estimation for heavy trucks based on vehicle dynamic simulation considering the road slope angle

A precise estimation of vehicle velocities can be valuable for improving the performance of the vehicle dynamics control (VDC) system and this estimation relies heavily upon the accuracy of longitudinal and lateral tyre force calculation governed by the prediction of normal tyre forces. This paper presents a computational method based on the unscented Kalman filter (UKF) method to estimate both longitudinal and lateral velocities and develops a novel quasi-stationary method to predict normal tyre forces of heavy trucks on a sloping road. The vehicle dynamic model is constructed with a planar dynamic model combined with the Pacejka tyre model. The novel quasi-stationary method for predicting normal tyre forces is able to characterise the typical chassis configuration of the heavy trucks. The validation is conducted through comparing the predicted results with those simulated by the TruckSim and it has a good agreement between these results without compromising the convergence speed and stability.     

Evaluating efficiency in the Norwegian bus industry using data envelopment analysis

This paper focuses on the performance of Norwegian bus companies subsidized by the government. The performance is evaluated from a productive efficiency point of view. The framework is that of a deterministic non-parametric Data Envelopment Analysis (DEA) approach to efficiency measurement. In this context several important issues are addressed: efficiency rankings, distribution and scale properties in the bus industry, potentials for efficiency improvements in the sector, the impact of ownership, area of operation and scope, and ways of improving efficiency in the sector. The findings show that the average bus company exhibits increasing return to scale in production of its services. The extent of such returns however vary, with size and is more prevalent among smaller companies. The average bus company is found to have a considerable input saving potential of about 28 percent. Neither economies of scope nor company ownership are found to have an influence on company performance. It is suggested that geographical factors need a closer attention in future research. The implications of DEA results are discussed and concluding remarks offered.