Workshop report - Beyond competitive tendering

Most countries contemplating the introduction of competition-based organizational forms did not perceive the British deregulated bus regime to be the way forward. A deeper analysis of facts and an international coverage of the local successes of that regime remained marginal and, as a result, the reputation of deregulated regimes remained bad or - at best - a contentious issue. The rush for competitive tendering was further stimulated by the European Commission’s endeavour to enact a Regulation that put forward competitive tendering of exclusive contracts as the preferred way to organise local public transport markets. Yet, as discussed in this workshop, deregulation in various guises may well play a growing role in local and regional transport. This is already visible in long-distance coach transport and in (international) European railway markets as from 2010. The workshop paper discusses whether such competition-based institutional alternatives to competitive tendering can provide efficiency and service improvements, how such competition-based alternatives should be ‘regulated’ and, alternatively, how a non-competitive direct award could perhaps still guarantee good performance.     

Evidence of convective instability in congested traffic flow: A systematic empirical and theoretical investigation

An extended open system such as traffic flow is said to be convectively unstable if perturbations of the stationary state grow but propagate in only one direction, so they eventually leave the system. By means of data analysis, simulations, and analytical calculations, we give evidence that this concept is relevant for instabilities of congested traffic flow. We analyze detector data from several hundred traffic jams and propose estimates for the linear growth rate, the wavelength, the propagation velocity, and the severity of the associated bottleneck that can be evaluated semi-automatically. Scatter plots of these quantities reveal systematic dependencies. On the theoretical side, we derive, for a wide class of microscopic and macroscopic traffic models, analytical criteria for convective and absolute linear instabilities. Based on the relative positions of the stability limits in the fundamental diagram, we divide these models into five stability classes which uniquely determine the set of possible elementary spatiotemporal patterns in open systems with a bottleneck. Only two classes, both dominated by convective instabilities, are compatible with observations. By means of approximate solutions of convectively unstable systems with sustained localized noise, we show that the observed spatiotemporal phenomena can also be described analytically. The parameters of the analytical expressions can be inferred from observations, and also (analytically) derived from the model equations.     

International comparison of market risks across shipping-related industries

This paper compares the behaviour of shipping and shipping-related company stock returns to reveal whether systematic risk differs from the average in the market and across sub-sectors of the maritime industry. Following an extensive collection of information through a postal questionnaire survey, 108 publicly listed shipping and shipping-related companies, across stock exchanges of the world, are classified by sector according to their core business activity. The Capital Asset Pricing Model (CAPM) is employed for the period 1996-1999 to model stock returns and measure sector βs (systematic risk). Stock returns over the period are mostly negative. The systematic risks of the Drilling and Offshore sectors are significantly higher than those of all other sectors, but are not different from each other. There is no significant difference between the systematic risks of the Bulk, Tanker, Container and Ferry sectors. The systematic risk of the Cruise sector lies somewhere between these two groups. There is no difference in the systematic risk of companies that diversified within shipping or shipping-related industries when compared to companies that diversified in other areas. Over all companies in the sample, βis lower than the market average, and so are the βs of the Ferry, Tanker, Bulk, Container and Yard sectors. Only the βof the Drilling sector is statistically higher than one, while the Cruise, Diversified and Offshore sectors are statistically one.     

Commercial public bus transport services in Germany: How a market in motion struggles with its regulatory framework

After decades of stagnation, the competitive market for commercial public bus transport services in Germany is beginning to move. Nevertheless, compared to the total market volume, the number of cases where competition is observable remains small. An empirical analysis of competition in the commercial services market as compared to competition in the non-commercial services market confirms that entry barriers do exist. These barriers clearly impede competitive developments in this embryonic market, which relies on the market initiatives of operators to develop. The paper identifies a key entry barrier in the institutional framework: for potential market entrants, the overall uncertainty regarding competitive procedures for commercial services is significantly higher than usual in tendering procedures. This high uncertainty poses the main disadvantage for newcomers as compared to incumbents.     

Three-phase traffic theory and two-phase models with a fundamental diagram in the light of empirical stylized facts

Despite the availability of large empirical data sets and the long history of traffic modeling, the theory of traffic congestion on freeways is still highly controversial. In this contribution, we compare Kerner’s three-phase traffic theory with the phase diagram approach for traffic models with a fundamental diagram. We discuss the inconsistent use of the term “traffic phase” and show that patterns demanded by three-phase traffic theory can be reproduced with simple two-phase models, if the model parameters are suitably specified and factors characteristic for real traffic flows are considered, such as effects of noise or heterogeneity or the actual freeway design (e.g. combinations of off- and on-ramps). Conversely, we demonstrate that models created to reproduce three-phase traffic theory create similar spatiotemporal traffic states and associated phase diagrams, no matter whether the parameters imply a fundamental diagram in equilibrium or non-unique flow-density relationships. In conclusion, there are different ways of reproducing the empirical stylized facts of spatiotemporal congestion patterns summarized in this contribution, and it appears possible to overcome the controversy by a more precise definition of the scientific terms and a more careful comparison of models and data, considering effects of the measurement process and the right level of detail in the traffic model used.     

Experiences with Competitive Tendering of Bus Services in Germany

Abstract

After a long transition period with only a few isolated procedures for competitive tendering, the market for German public transport bus services has seen numerous such tenders in recent years. The results are complex. From the public transport authorities’ point of view, the main effects are a decrease in subsidy payments, with relatively low expenses relating to the tendering process (allocation, contract management). The overall level of competition is high, with five to seven bidders on average, although this has been declining in recent years. Entry barriers have been identified at significant levels for several parameters, especially with respect to the volume tendered and the revenue risk to be borne by the operator out of net‐cost contracts. Demonstrably small‐ and medium‐sized transport operators have been able to increase their market share in the starting phase of introducing tendering, with diminishing success rates in recent years. Due to the increased quality requirements in competitive tendering, the quality of public transport available has improved considerably, and environmental standards have been better implemented and sustained. As far as employees are concerned, a trend towards wages below the wage rate of private operators cannot be observed. However, their level is well below the level of public incumbent operators.     

Adaptive cruise control design for active congestion avoidance

We present an adaptive cruise control (ACC) strategy where the acceleration characteristics, that is, the driving style automatically adapts to different traffic situations. The three components of the concept are the ACC itself, implemented in the form of a car-following model, an algorithm for the automatic real-time detection of the traffic situation based on local information, and a strategy matrix to adapt the driving characteristics (that is, the parameters of the ACC controller) to the traffic conditions. Optionally, inter-vehicle and infrastructure-to-car communication can be used to improve the accuracy of determining the traffic states. Within a microscopic simulation framework, we have simulated the complete concept on a road section with an on-ramp bottleneck, using empirical loop-detector data for an afternoon rush-hour as input for the upstream boundary. We found that the ACC vehicles improve the traffic stability and the dynamic road capacity. While traffic congestion in the reference scenario was completely eliminated when simulating a proportion of 25% ACC vehicles, travel times were already significantly reduced for much lower penetration rates. The efficiency of the proposed driving strategy even for low market penetrations is a promising result for a successful application in future driver assistance systems.     

Validation of traffic flow models with respect to the spatiotemporal evolution of congested traffic patterns

We propose a quantitative approach for calibrating and validating key features of traffic instabilities based on speed time series obtained from aggregated data of a series of neighboring stationary detectors. The approach can be used to validate models that are calibrated by other criteria with respect to their collective dynamics. We apply the proposed criteria to historic traffic databases of several freeways in Germany containing about 400 occurrences of congestions thereby providing a reference for model calibration and quality assessment with respect to the spatiotemporal dynamics. First tests with microscopic and macroscopic models indicate that the criteria are both robust and discriminative, i.e., clearly distinguishes between models of higher and lower predictive power.     

The perception and image of shipping

The image of the shipping industry plays a vital role in developing maritime transport as a major future, sustainable transport alternative. In particular, it is crucial to understand the image the shipping industry has among young people and the anatomy of the concept in order to be able to effectively promote careers in shipping, to cultivate shipping as an attractive labour market and to develop attractive educational programmes. The focus of this paper is the image of the shipping industry. This study reports on the findings of a large-scale survey of the image of shipping- and image-related concepts among upper secondary school pupils in Sweden, Norway and Greece. We define and analyse empirically by means of multivariate statistical analysis the anatomy of the image concept. We identify various image dimensions, estimate how young people rate the shipping industry along these dimensions and estimate their relative importance to young people who are planning their future careers. The results from this study can be used as a base for describing and explaining the images that young people have of the shipping industry. Such knowledge is fundamental for deriving and developing constructive strategies to promote careers in shipping, to adapt shipping to the expectations of young people and to develop creative and relevant educational programmes. Finally, understanding the image of shipping among young people is important not only for the shipping industry, but for other stakeholders as well, such as ship-owners associations, trade associations, labour unions, transport authorities and administrations and policy makers at the national and supra-national level.