Estimating the willingness to pay and value of risk reduction for car occupants in the road environment

In recent years there has been a re-focus on the valuation of a statistical life from the ex post or human capital method to an ex ante willingness to pay (WTP) approach. This is in part a recognition that we may have been undervaluing the cost of fatalities and injuries to society associated with crashes, but also a strong belief in the need to focus on establishing the amount, ex ante, that individuals are willing to pay to reduce the risk of exposure to circumstances that might lead to death or degree of injury on the road network. This study has developed a framework in which to identify the degree of preference heterogeneity in willingness to pay by individuals who are drivers or passengers in cars to avoid being killed or injured. A stated choice experiment approach is developed. The empirical setting is a choice of route for a particular trip that a sample of individuals periodically undertakes in Australia. The particular trip is described in enough detail to provide the respondent with a familiar market environment, providing all the relevant background information required for making a decision. Mixed logit models are estimated to obtain the marginal (dis)utilities associated with each influence on the choice amongst the attribute packages offered in the stated choice scenarios. These estimates are used to obtain the WTP distributions for fatality and injury avoidance, which are then aggregated to obtain estimates of the value of risk reduction (VRR), of which the fatality class is also known as the value of a statistical life (VSL).     

Random covariance heterogeneity in discrete choice models

In this paper, we extend the standard discrete choice modelling framework by allowing for random variations in the substitution patterns between alternatives across respondents, leading to increased model flexibility. The paper shows how such a Mixed Covariance model can be specified either with purely random variation or with a mixture of random and deterministic variation. Additionally, the model can be based on an underlying GEV or ECL structure. Finally, the model can be specified as a continuous mixture or as a discrete mixture. An application on Stated Preference data for the choice of departure time and travel mode shows that important gains in model performance can be obtained by allowing for random covariance heterogeneity. Furthermore, the approach leads to significant differences in the implied willingness to pay measures, and the substitution patterns between alternatives.     

Workshop report - Public policy and transport

This workshop considered the wider public policy goals of a range of transport interventions. Particular attention was paid to assessing the role of integration of the different components of the transport system and of the integration of transport with other economic sectors. This assessment was informed by Ray Pawson’s realist evaluation approach, with its emphasis on the inter-relationships between context, process and outcome. The context was provided by case studies covering small urban areas, large urban areas and inter-urban corridors. The three key processes identified related to a regulated system with public ownership and control, a deregulated system with private sector ownership (‘competition in the market’) and a system in which there was public planning of the transport system but private provision (‘competition for the market’). Outcomes can be assessed using cost-benefit analysis tools to determine impacts on economic welfare or more qualitative approaches can be used to determine the extent to which accessibility or sustainability goals have been achieved. The evidence provided suggests that wider public policy goals are more important for urban than for inter-urban transport and it thus in urban areas where integration should be pursued with most vigour. The most relevant process for achieving this would seem to be variants of the competition for the market model. Some policy recommendations are made and implications for further research and for future conferences assessed.     

What’s so funny about peace, love and transport integration?

The 1998 White Paper proposed integration as the solution to Great Britain’s land transport problems. Most commentators agree that this much vaunted New Deal for Transport has been a failure. Yet some ten years later policy papers from bodies such as the Institution of Civil Engineers and the Centre for Cities are still proposing integration as a possible panacea.There are a number of reasons for the failure of integrated transport over the last decade. The first is the failure to define the concept. The second is the failure to operationalise the concept. The third is the lack of an evidence base on the success of integrated transport policies. Evidence is now emerging in Britain on the benefits (and indeed the costs) of some aspects of integrated transport policies. The fourth, and perhaps the most crucial, is the lack of will in terms of politicians, civil servants and the public at large, to adopt the behavioural changes necessary for an integrated transport policy to be successful. A series of organisational and funding changes are proposed that could advance the prospects for integration.     

Investigating links between transport disadvantage, social exclusion and well-being in Melbourne - Updated results

This paper updates results of an international study aimed at quantifying the links between transport disadvantage (TD), social exclusion (SE) and well-being (WB) in Melbourne, Australia. The study extends knowledge associated with SE and transport by quantify social and behavioural implications of lack of public and private transport and the nature of the social WB benefits associated with improving services.Study aims and methodology are outlined. Recent findings covered relate to car ownership on the urban fringe, patterns of transport disadvantage, the analysis of time poverty related to transport disadvantage, measuring the economic value of additional mobility and use of a Structural Equation Model (SEM) to relate WB and SE to TD and a series of explanatory factors.Overall results suggest that those without a car on the urban fringe adjust well with their circumstances by living close to activity centres. They demonstrate sustainable choices, trading off budgets and home location to balance mobility and accessibility. Poorer households with high car ownership value mobility and cheaper more remote fringe dwellings but demonstrate numerous strategies to reduce high car costs which are acknowledged as a significant burden. Analysis identifies 4 key types of transport disadvantage including a ‘vulnerable/impaired’ group which should be of much greater concern for targeted policy than others due to poor scoring on SE and WB scales. The economic value of new mobility is also explored with results suggesting $AUD 20 per average new trip which is four times larger than conventional values for generated travel.Analysis has also suggested that transport disadvantage can relate to socially advantaged as well as socially disadvantaged groups through time poverty. This was found to be an important mitigating factor when relating TD to WB. A statistically reliable structural equation model is developed suggesting the SE-WB link is strong (−.87) with a modest link between TD-SE (.27).Areas for future research in the project are also summarised.     

Goal achievement with trusting partnerships at the tactical level

Recent Thredbo Conferences have begun to explore the importance of the relationship between public transport service purchaser and provider in the development of successful public transport services. However, practical examples to test the trusting partnership model are rare. Bus service planning and delivery in Melbourne, Australia, has pioneered the trusting partnership approach, from agreement about desirable service standards and requisite operator qualifications (at the Tactical level) to detailed service delivery contracts. New negotiated performance-based metropolitan bus contracts commenced in January 2009, embodying principles discussed in previous Thredbo Conferences. This paper reports on the Tactical planning process that agreed service standards and the subsequent contract negotiation process, reflecting a trusting partnership between purchaser and provider, while remaining transparent and accountable and maintaining performance pressure on the provider. It shows how patronage growth rates have increased dramatically and identifies areas where further enhancements should be explored in the contracting area.     

Some observed details of freeway traffic evolution

Certain details of traffic evolution were studied along a 2 km, homogenous freeway segment located upstream of a bottleneck. By comparing (transformed) cumulative curves constructed from the vehicle counts measured at neighboring loop detectors, it was found that waves propagated through queued traffic like a random walk with predictable statistical variation. There was no observed dependency of wave speed on flow. As such, these waves neither focused nor fanned outward and shocks arose only at the interfaces between free-flowing traffic and the back of queues. Although these traffic features may have long been suspected, actual observations of this kind have hitherto not been documented. Also of note, the shocks separating queued and unqueued traffic sometimes exhibited unexpectedly long transitions between these two states. Finally, some observations presented here corroborate earlier reports that, in unqueued traffic, vehicle velocity is insensitive to flows and that forward-moving changes in traffic states therefore travel with vehicles. Taken together, these findings suggest that certain rather simple models suffice for describing traffic on homogeneous freeway segments; brief discussion of this is offered in Section 5.     

Comparison of sediment profile image data with profiles of oxygen and Eh from sediment cores

A study of oil and gas development in the Gulf of Mexico provided a unique opportunity to compare data from sediment profile images (SPI) with that of sediment cores collected at locations in the central Gulf of Mexico from 1034 to 1175 m. Variables measured from SPI included sediment grain-size, sediment texture, apparent depth of oxygen penetration (aDOP) into the sediments, and parameters related to biogenic activity (tubes, burrows, feeding pits or mounds, and subsurface feeding voids). Variables measured from the sediment cores included sedimentation rate, dissolved oxygen profiles, and redox potential (Eh). There was a high degree of concordance between the two data sets based on correlation analysis. For example, the correlation between aDOP and maximum penetration of oxygen into the sediment was 0.69. For deep-sea sediment, SPI provides a means by which general geochemical conditions of near surface sediment can be remotely assessed providing a quick method for mapping surficial geochemistry over large areas.