Privatisation and the quality of rail services

Using the concept of generalised costs to reflect quality in rail services, we consider the level of provision and quality of these services in the various forms they may take in a privatised environment within a model where we assume linear and separable demand and cost functions for analytical simplicity. Using the Pareto-efficient output and quality outcomes under a fully integrated system for reference (as well as those for a fully integrated profit-maximising monopolist) we show that if either bilateral monopoly or complementary monopoly emerge as a market structure the output of train services and their quality will generally fall. In the case of the emergence of both bilateral monopoly and complementary monopoly our analysis again suggests poor welfare outcomes. The implication that can be drawn from our analysis is that a regulator of a privatised rail system faces some severe problems if she is to attain the appropriate welfare targets.     

Traffic assignment by trip type using volume restraint and link restraint for application in small urban areas

This research involved the development of a new traffic assignment model consisting of a set of procedures for an urbanized area with a population of 172,000. Historical, social, and economic data were used as input to conventional trip generation and trip distribution models to produce a trip table for network assignment. This fixed table was divided into three trip types: external-external trips, external-internal trips, and internal-internal trips. The methodology used to develop the new traffic assignment model assigned each of the trip types by varying the diversion of trips from the minimum path. External-external trips were assigned on a minimum path routing and external-internal trips were assigned with a slight diversion from the minimum path. Internal-internal trips were assigned with more diversion than external-internal trips and adjusted by utilizing iterative volume restraint and incremental link restraint. A statistical analysis indicated that assigning trips by trip types using trip diversion and volume and link restraint produces a significant improvement in the accuracy of the assigned traffic volumes.     

A maritime productivity study 1859-1919

This is one of two papers designed to test the ability of a theoretical model of productivity measurement [1] with times series empirical data. The analysis was able to identify trends in productivity growth for sailing ships and stcamships. scparating long and short run components . One of the interesting features of the findings is that the long run growth rate is the same for both sailing and steamships. Although sail and steam appear to be two unique technologies, it is found that technologica progress is evolutionary not revolutionary.

The techique using covariance analysis proved useful for times series productivity measurement.     

Rogue ships—a shipowner's view

The paper, first of all, examines what a 'rogue ship' is and then moves on to the various practical solutions as to how to deal with the problem. There is no one single answer but the author believes that it is in the interest of society in general to get rid of these ships.     

Latent structure in road systems

The application of Q-analysis to road transport systems is introduced in this paper, but no prior knowledge of the methodology is assumed. It is argued that the route-link relation of transport systems has a connectivity structure overlooked by conventional transportation theory, and that this structure constrains traffic flow. This is illustrated at the micro-level by a complicated road intersection, and at the macro-level with a simple analysis of a town. The representation of road systems is discussed in this context, and it leads to a new result called the Link Face Theorem. It is suggested that the conventional theory can be usefully extended by studying the latent structure of road systems which is presently overlooked.     

Transport planning with multiple criteria: The analytic hierarchy process applications and progress review

Five examples of applications of the Analytic Hierarchy Process (AHP) are made to illustrate the different uses of this ratio scale multicriteria decision method in transportation. They include a commuter route selection hierarchy, a best mix of routes to Pittsburgh's new International Airport, a benefits/costs hierarchy to choose the best mode to cross a river, a planning hierarchy for a transport system and a simple dependence with feedback cycle to choose a car when criteria depend on the alternatives. For a better appreciation of the use and power of the method, the examples are followed by a resume of developments in research on the (AHP) in the last few years.     

Crosswind Sensitivity of Passenger Cars and the Influence of Chassis and Aerodynamic Properties on Driver Preferences

Results of vehicle crosswind research involving both full-scale driver-vehicle tests and associated analyses are presented. The paper focuses on experimental crosswind testing of several different vehicle configurations and a group of seven drivers. A test procedure, which utilized wind-generating fans arranged in alternating directions to provide a crosswind “gauntlet”, is introduced and described. Driver preferences for certain basic chassis and aerodynamic properties are demonstrated and linked to elementary system responses measured during the crosswind gauntlet tests. Based on these experimental findings and confirming analytical results, a two-stage vehicle design process is then recommended for predicting and analyzing the crosswind sensitivity of a particular vehicle or new design.     

Environmental changes in the western Black Sea related to anthropogenic and natural conditions

The Black Sea northwestern shelf (NWS) ecosystem has been subjected to the strongest anthropogenic pressure of the entire Black Sea as about 80% of the freshwater runoff is discharged there.This paper presents a review of the global environmental changes related mainly to increased eutrophication in the western Black Sea basin.A case study (CoMSBlack 92a cruise) attempts to highlight the interaction of some natural and anthropogenic factors responsible for specific chemical and biological features in the western Black Sea environment. The significance of processes located near the Danube river mouth, which, due to their relatively small space scale, have not been recognized before, is clarified. Hydrological processess of specific importance to the distribution and transformation of antropogenic inputs are river plume dynamics, coastal upwelling and mixing and downwelling over the shelf break and slope in this part of the basin. A layer of low hydrological variability (“conservative layer”) appears to be a natural feature of the area, hypothesized to precondition specific biological and chemical processes there.The results suggest that the interplay between the Danube anthropogenic nutrient load with the natural hydrological fronts and gradients provides opportunities for enhanced biological activity thus contributing to the global environmental changes in the Black Sea NWS.     

Simplical decomposition of the asymmetric traffic assignment problem

This paper presents a convergent simplicial decomposition algorithm for the variational inequality formulation of the asymmetric traffic assignment problem. It alternates between generating minimum path trees based on the cost function evaluated at the current iterate and the approximate solving of a master variational inequality subject to simple convexity constraints. Thus it generalizes the popular Frank-Wolfe method (where the master problem is a line search) to the asymmetric problem. Rules are given for dropping flow patterns which are not needed to express the current iterate as a convex combination of previous patterns. The results of some computational testing are reported.