Jeremy Shires

DRIVER RESPONSE TO VARIABLE MESSAGE SIGNS: A STATED PREFERENCE INVESTIGATION

Abstract This paper uses a Stated Preference approach to undertake a detailed assessment of the effect on drivers’ route choice of information provided by variable message signs (VMS). Although drivers’ response to VMS information will vary according to the availability of alternative routes and the extent to which they are close substitutes, our findings show that route choice can be strongly influenced by the provision of information about traffic conditions ahead. This has important implications for the use of VMS systems as part of comprehensive traffic management and control systems. The principal findings are that the impact of VMS information depends on: the content of the message, such as the cause of delay and its extent; local circumstances, such as relative journey times in normal conditions; and drivers’ characteristics, such as their age, sex and previous network knowledge. The impact of qualitative indicators, visible queues and delays were examined. It was found that not only is delay time more highly valued than normal travel time, which is to be expected, but that drivers become more sensitive to delay time as delay times increased across the range presented.

An international meta-analysis of values of travel time savings

Values of travel time savings are often used in cost-benefit analysis of transport projects and policies, and also to compute generalised travel costs. There has been considerable debate as to whether different research methods (e.g. stated versus revealed preference) will lead to different values of travel time savings, and which segmentations (e.g. by income or mode) are most important to capture the heterogeneity in these values. In addition there are many countries where no specific valuation studies have been done. In this paper new equations are estimated on the outcomes of value of travel time savings studies from various countries. In the data set, several countries appear more than once, which is taken into account by estimating random effects panel models. The meta-analysis sheds some new light on the variation of the value of travel time savings by income, country, travel purpose, mode, distance and by survey method. Furthermore, the resulting meta-models are applied to produce new values of travel time savings for business travel, commuting and for other purposes in passenger transport, for 25 European Union Member states. Similar methods could be used to statistically analyse studies carried out on other non-monetary effects, both for transport and non-transport projects, and for inclusion in cost-benefit analysis.

AN ASSESSMENT OF ADVANCED TRANSPORT TELEMATICS EVALUATION PROCEDURES

This paper reviews and critically assesses procedures which have been adopted to evaluate Advanced Transport Telematics (ATT) projects. The importance of such a review at this juncture stems from the changing position of ATT in transport planning. ATT is no longer simply a field for experimentation, where technical feasibility and user acceptance are dominant concerns. Rather it is a potential mainstream contributor to the functioning of road transport systems. For this reason, ATT project appraisal needs to be developed to the same form, level of sophistication and consistency as the appraisal of conventional transport infrastructure investment. Based on the review set out here, we argue that appropriate methods have not yet been established which, in turn, poses a number of challenging questions, since current socio‐economic evaluation procedures are not directly suited to either measuring or evaluating many of the impacts which ATT schemes are implemented to achieve.

Impact of delays on passenger train services: evidence from Great Britain

The impact of delays on passenger railways, with specific reference to the national rail network in Great Britain, is examined. A key distinction is made between punctuality (trains running late) and reliability (trains canceled). In Britain these have been combined into a public performance measure, which deteriorated markedly as a consequence of the Hatfield accident in 2000 but has since gradually improved. Causes of delay can be associated with train operators, infrastructure authorities, and external factors. In Great Britain, train operators apparently have been better able to manage delay than the infrastructure authority. Traditional means of valuing delay have used stated preference methods that incorporate a measure of mean lateness and have shown that a minute of late time is typically valued as equivalent to 3 min of timetabled journey time. This is referred to as the reliability multiplier. Studies have also focused on the value placed on the standard deviation of journey time and compare this valuation against that of mean journey time to produce the reliability ratio. The most recent work finds that the reliability ratio may be higher than previously thought, whereas the reliability multiplier may be lower than previously thought, especially for long journeys. In addition, recent work that has made use of revealed preference data to infer elasticities of demand with respect to delays indicates that most market segments are relatively insensitive to delays. In total, this recent work suggests that passengers in Britain may be becoming less sensitive to reliability, and reasons for this are examined.

Employer Expectations for Commuting and Business-Related Travel in an Environment Rich in Information and Communication Technologies

The collection and the analysis of data on working from home (teleworking) and on the use of information and communication technologies (ICT) to substitute for business travel are described, and conclusions are drawn. Data were collected from senior management by using a web-based questionnaire incorporating several innovative features; in addition to data on current and expected levels of home-working and business travel in a range of ICT scenarios, data were collected on the respondents perception of the impact of different factors on future levels of these activities. Also, to test the robustness of respondent opinions, the impact of alternative versions of a briefing text—one positive and one negative about the role of ICT—on respondent expectations was evaluated. Analysis revealed that a number of factors that are often ignored or taken as constant would be influential in the future levels of homeworking and business travel. Generally, issues of cost appeared to be much less influential than the spe...

A latent class approach to dealing with respondent uncertainty in a stated choice survey for fare simplification on bus journeys

This article presents the findings of an analysis making use of a stated choice survey looking at bus travellers’ preferences for specific fare structures. Specifically, respondents were given the choice between the current fare structure, which is largely distance based, a fixed fare structure, and a zonal fare structure. It was anticipated that there might be two sources of substantial respondent uncertainty, in relation to the current fare as well as the number of zones a specific journey covers. These two types of uncertainty could create a significant level of bias in the results, and in this article, we put forward a modelling approach based on a latent class structure that allows us to accommodate this respondent uncertainty and avoid the source of bias. Latent class structures are used widely to allow for variations in sensitivities across individual decision makers; here, we show how such a structure is equally well suited to deal with respondent uncertainty expressed through variations in the perceived fares of different journey options.

A generalized approach for measuring the marginal social costs of road transport in Europe

ABSTRACT Social marginal cost pricing requires bottom-up calculations of social marginal costs for all circumstances. Because this is not practicable for policymaking, we suggest an approach to generalize available cost estimates and present results from this for two case studies. We conclude that in the peak period congestion costs are the most important externality of road use, and that accidents, wear and tear, and noise costs all appear to be more important than global warming. This suggests that the policy priority should be measures to tackle the other elements of transport externalities alongside global warming costs.