https://hdl.handle.net/2123/17664 2026-06-14T13:32:06Z https://hdl.handle.net/2123/19449 Efficient Designs for Alternative Specific Choice Experiments Bliemer, Michiel CJ; Rose, John M In the past, research on the construction of efficient designs for stated choice experiments has been limited to unlabeled experiments with generic parameter estimates. In this paper, by deriving the asymptotic (co)variance matrix for the alternative-specific MNL model, the authors are able to generate efficient alternative-specific experiments. The authors show that D-error assuming prior parameter values equal to zero is unable to explain statistical efficiency in orthogonal designs and that wide attribute levels are likely to yield more reliable parameter estimates than using narrow attribute levels. The authors also show that the D-optimality criterion may yield inefficient parameter estimates for some design attributes given that trade-offs are made between the efficiencies of different parameter estimates. 2005-03-01T00:00:00Z https://hdl.handle.net/2123/19538 The implications of respondent attribute processing rules and experimental design on WTP in stated choice experiments Hensher, David A. Individual’s process the information in stated choice (SC) experiments in many different ways. In order to accommodate decisions rules that are used in processing information, there is good sense in conditioning the parameterisation of stated choice design attributes on these rules. In particular, rules might be invoked to cope with the dimensionality of the SC design. In this paper we investigate the impact of rules such as attribute aggregation and reference dependency on preference profiles for specific design attributes, as well as the design specification, as we vary the dimensionality of an SC design. Prior to identifying the empirical differences in valuation of travel time savings due to design specification, we account for scale differences from pooling 16 stated choice designs. The heteroscedastic extreme value logit model is estimated to identify the role of design dimensionality and attribute processing rules, after accounting for scale differences across the pooled data designs The empirical evidence, drawn from a study in Sydney of car commuter route choice, suggests that accounting for the way that stated choice designs are processed, given their dimensionality, does make a statistically significant difference on measures of willingness to pay, as does accounting for scale differences between pooled data designs. This evidence has value in guiding the design of SC experiments and in adjusting results from different SC designs when comparing the evidence. 2005-06-01T00:00:00Z https://hdl.handle.net/2123/19450 Accounting for Heterogeneity in the Variance of Unobserved Effects in Mixed Logit Models Greene, William; Hensher, David A.; Rose, John The growing popularity of mixed logit to obtain estimates of willingness to pay (WTP) has focussed on the distribution of the random parameters and the possibility of estimating deep parameters to account for heterogeneity around the mean of the distribution. However the possibility exists to add further behavioural information associated with the variance of the random parameter distribution, through parameterisation of its heterogeneity (or heteroskedasticity). In this paper we extend the mixed logit model to account for this heterogeneity and illustrate the implications this has on the moments of the willingness to pay for travel time savings in the context of commuter choice of mode. The empirical study highlights the statistical and behavioural gains but warns of the potential downside of exposing the distribution of the parameterised numerator and/or denominator of the more complex WTP function to a sign change and extreme values over the range of the distribution. 2005-01-01T00:00:00Z https://hdl.handle.net/2123/19464 Road User Charging: The Global Relevance of Recent Developments in the United Kingdom Hensher, David A.; Puckett, Sean Charging users of the roads for the costs they impose on the system is not new. Economists have been promoting its virtues for as long as arguments about economic efficiency have been in print. What is different today is that a growing number (but by no means all) of decision makers are showing a greater interest and commitment to finding ways to improve the efficiency of the road system, be it through infrastructure expansion and/or other means. Of special interest is the growing level of traffic congestion, and a feeling of almost helplessness, that we seem to have failed in finding a way forward to maintain traffic congestion at levels that are acceptable to the public, and are consistent with principles of good economic practice. The literature abounds with suggestions on how this might be achieved, focused primarily on various pricing regimes that say as much as about levels of charges as they do about the role of the revenue raised, the latter as controversial as the former. The current state of technology provides a capability to introduce sophisticated charging mechanisms. We are at a stage in the evolution of ‘solutions’ to dealing with inefficient road use and provision of road funds that offers real prospects of delivering outcomes that can align with political, social and user demands and expectations. This paper provides a global perspective on the road to efficiency, using the UK contributions in the special issue as a backdrop of what can be done. The issues and challenges are sufficiently global to enable the contributions to be of immediate relevance beyond the UK. 2005-09-01T00:00:00Z https://hdl.handle.net/2123/19447 Sample optimality in the design of stated choice experiments Rose, John M; Bliemer, Michiel CJ Stated choice (SC) experiments represent the dominant data paradigm in the study of behavioral responses of individuals, households as well as other organizations, yet little is known about the sample size requirements for models estimated from such data. Current sampling theory does not adequately address the issue and hence researchers have had to resort to simple rules of thumb or ignore the issue and collect samples of arbitrary size, hoping that the sample is sufficiently large enough to produce reliable parameter estimates. In this paper, we demonstrate how to generate efficient designs (based on D-efficiency and a newly proposed sample size S-efficiency measure) using prior parameter values to estimate multinomial logit models containing both generic and alternative-specific parameters. Sample size requirements for such designs in SC studies are investigated. Using a numerical case study, we show that using S-efficiency can substantially reduce the sample size required of SC studies. 2005-06-01T00:00:00Z https://hdl.handle.net/2123/19528 Recovering costs through price and service differentiation: Accounting for exogenous information on attribute processing strategies in airline choice Rose, John M; Hensher, David A.; Greene, William H The entry of low cost airlines has thrown out a challenge to all airlines to find ways of attracting passengers, through a mix of fare discounting, greater frequency, improved flight times and no-frill’s levels of on-board service. All of these competitive strategies have an impact on cost recovery. As airlines seek business in an increasingly heterogeneous passenger market, a greater understanding of what matters to potential passengers in choosing an airline grows in importance. Which attributes really do matter to specific classes of passengers? Traditional studies of passenger airline choice assume that all attributes matter, but some to a lesser extent. What happens to the empirical evidence on willingness to pay when specific attributes are totally ignored by particular passengers? In this paper, we examine the impact of individual-specific attribute processing strategies (APS) on the inclusion/exclusion of attributes on the parameter estimates and behavioural outputs of models of airline service and fare level choice. Current modelling practice assumes that whilst respondents may exhibit preference heterogeneity, they employ a homogenous APS with regards to how they process the presence/absence of attributes of stated choice (SC) experiments. We demonstrate how information collected exogenous of the SC experiment on whether respondents either ignored or considered each attribute of the SC task may be used in the estimation process, and how such information may be used to provide outputs that are APS segment specific. Accounting for the inclusion/exclusion of attributes has important implications on the willingness to pay for varying levels of service. 2005-06-01T00:00:00Z https://hdl.handle.net/2123/19463 Community Perceptions of ‘TravelSmart’ Behaviour in South Australia Bertoia, Tony; Tideman, Jill; Stopher, Peter R Insights from psychology and marketing have recently led to an alternative to information-based behaviour change campaigns, known as community-based social marketing. The key to this approach is the identification of barriers that prevent individuals from engaging in sustainable behaviours, and the implementation of strategies (‘tools’) specifically targeted at addressing these perceived barriers. The aim of the current study was to contribute to travel behaviour change research by enhancing our understanding of the reasons people choose to engage or not engage in reducing car use. Face-to-face interviews were conducted on a sample of 392 individuals from the western Adelaide metropolitan region. The survey instrument utilised various questioning techniques such as open-ended questions, agreement scales (to attitudinal statements), and importance scales, to identify the perceived benefits and barriers to reducing car use among members of this community. The survey was conducted prior to the commencement of the TravelSmart intervention in the western suburbs of the Adelaide metropolitan region. The survey identified ‘convenience’ and the importance of ‘making small changes’ as the dominant factors distinguishing those who identify themselves as actively trying to reduce their car use from those who are not currently active in this behaviour. The results obtained from this study suggest the existence of key differences in the priorities of people who are currently active and currently inactive in reducing car use. 2005-08-01T00:00:00Z https://hdl.handle.net/2123/19525 Accounting for Exogenous Information on Decision Maker Processing Strategies in Models of Discrete Choice: Attribute Exclusion Strategies in Airline Choice Rose, John M; Hensher, David A.; Greene, William H In this paper, we examine the impact of individual specific information processing strategies (IPS) on the inclusion/exclusion of attributes on the parameter estimates and behavioural outputs of models of discrete choice. Current modelling practice assumes that whilst respondents may exhibit preference heterogeneity, they employ a homogenous IPS with regards to how they process the presence/absence of attributes of SC experiments. We demonstrate how information collected exogenous of the SC experiment on whether respondents either ignored or considered each attribute of the SC task may be used in the estimation process, and how such information may be used to provide outputs that are IPS segment specific. We contend that accounting the inclusion/exclusion of attributes will result in behaviourally richer population parameter estimates. 2005-08-01T00:00:00Z https://hdl.handle.net/2123/19494 Auction Settings Impacts on the Performance of Truckload Transportation Marketplaces Figliozzi, Miguel Andres; Mahmassani, Hani S.; Jaillet, Patrick This paper compares the performance of different sequential auction settings for the procurement of truckload services. In this environment, demands arrive randomly over time and are described by pick up, delivery locations and hard timewindows. Upon demand arrival, carriers compete for the loads. Different auction and information disclosure settings are studied. Learning methodologies are discussed and analyzed. Simulation results are presented. 2005-03-01T00:00:00Z https://hdl.handle.net/2123/19523 The implications on willingness to pay of a stochastic treatment of attribute processing in stated choice studies Hensher, David A.; Rose, John; Bertoia, Tony Individuals processing the information in a stated choice experiment are asked to evaluate a set of attributes offered and to choose their most preferred alternative. It has always been thought that some attributes are not attended to in this process for many reasons, including a coping strategy to handle their perception of the complexity of the choice task. However analysts proceed, with rare exception, to estimate discrete choice models as if all attributes have influenced the outcome to some degree. In this paper we investigate the implications of bounding the attribute processing task by attribute elimination through not attending to one or more attributes. Using a sample of car non-commuters in Sydney we estimate a mixed logit model in which all attributes are assumed to be attended to, and models which assume that certain attribute(s) are not attended to, based on supplementary information provided by respondents. The supplementary information is accounted for in a deterministic and a stochastic way; the latter in recognition of the analyst’s lack of full information on why a specific attribute processing (AP) strategy was adopted by each sampled individual. We compare the value of travel time savings distribution under alternative attribute processing regimes. As expected, there are noticeable variations in the mean and standard deviation willingness to pay (WTP) across the three AP strategies. 2005-06-01T00:00:00Z https://hdl.handle.net/2123/19479 The signs of the times: Imposing a globally signed condition on willingness to pay distributions Hensher, David A. A feature of recent developments in choice models that enable estimation of the distribution of willingness to pay (WTP), is that the sign of the distribution can change over the range. Behaviourally this often makes little sense for attributes such as travel time on non-discretionary travel, despite a growing recognition of positive utility over some travel time ranges. This can in part be attributed to the analytical distribution that is selected (except the cumbersome lognormal), many of which are unconstrained over the full range. Although a number of analysts have imposed constraints on various distributions for random parameters that can satisfy the single-sign condition, these restrictions are, with rare exception, only satisfied for the mean and the standard deviation estimates of a random parameter. When heterogeneity around the mean and/or heteroscedasticity around the standard deviation is allowed for, however, the constraint condition is often not satisfied. Given the popularity of distributions other than the lognormal, in order to satisfy the sign condition under the most general form of parameterisation, we need to impose a global sign condition. In this paper we show how this might be achieved in the context of the valuation of travel time savings for car commuters choosing amongst an offered set of route-specific travel times and costs. We illustrate the impact of the constraint under a globally constrained Rayleigh distribution for total travel time parameterisation, contrasting the evidence with a multinomial logit model and a range of other distributional assumptions within the mixed logit framework 2005-07-01T00:00:00Z https://hdl.handle.net/2123/19521 Designing a Procedure to Undertake Long Term Evaluation of the Effects of TravelSmart Interventions Stopher, Peter; Greaves, Stephen; Xu, Min; Lauer, Natalie As part of the program of strategies to reduce the emission of greenhouse gases in Australia, the ACT, Queensland, South Australian, and Victorian governments have joined together to undertake a program of voluntary travel behaviour change (VTBC) strategies. This paper outlines and evaluates the options available for a long term monitoring program to measure the effects of VBTC interventions. In particular, it deals with which measurement method to employ, how to conduct the sampling, how frequently to measure the population, and how to enhance the primary data set for a national monitoring program. The paper explores a wide range of options available to the project partners. At a minimum, it is recommended that a purpose-specific annual odometer survey be conducted on a rotating panel of households. However, a far richer data set would be provided through the use of personal global positioning systems (GPS) devices for data collection over periods of up to 1 month at six-monthly intervals on a panel of households. A number of combinations of these two survey methods are suggested. The paper considers the use of established tools, such as travel diaries, and established surveys, such as the SMVU, but ultimately finds them inadequate for the task. In recommending pioneering new monitoring methods and practices, the authors acknowledge a number of areas which will require further investigation. Specifically, further investigation of issues relating to respondent burden and data variability in different survey designs will need to be conducted. Much work will be required to develop and test the instruments to be employed in the administration of the options recommended in this paper. 2005-06-01T00:00:00Z https://hdl.handle.net/2123/19422 The implications of Willingness to Pay of Respondents Ignoring Specific Attributes Hensher, David A.; Rose, John; Greene, William H Individuals processing the information in a stated choice experiment are typically assumed to evaluate each and every attribute offered within and between alternatives, and to choose their most preferred alternative. However, it has always been thought that some attributes are ignored in this process for many reasons, including a coping strategy to handle one’s perception of the complexity of the choice task. Nonetheless, analysts typically proceed to estimate discrete choice models as if all attributes have influenced the outcome to some degree. The cognitive processes used to evaluate trade-offs are complex with boundaries often placed on the task to assist the respondent. These boundaries can include prioritising attributes and ignoring specific attributes. In this paper we investigate the implications of bounding the information processing task by attribute elimination through ignoring one or more attributes. Using a sample of car commuters in Sydney we estimate mixed logit models that assume all attributes are candidate contributors, and models that assume certain attributes are ignored, the latter based on supplementary information provided by respondents. We compare the value of travel time savings under the alternative attribute processing regimes. Assuming that all attributes are not ignored and duly processed, leads to estimates of parameters which produce significantly different willingness to pay (WTP) to that obtained when the exclusion rule is invoked. 2005-01-01T00:00:00Z https://hdl.handle.net/2123/19403 The implications of respondent information processing rules on preference revelation in stated choice experiments Hensher, David A. Individual’s process the information in stated choice (SC) experiments in many different ways. In order to accommodate decisions rules that are used in processing information, there is good sense in conditioning the parameterisation of stated choice design attributes on these rules. In particular, rules might be invoked to cope with the dimensionality of the SC design. The information processing strategy (IPS) can act as a qualifier of heterogeneity in the mean and/or heteroscedasticity of the distribution of the marginal (dis)utility of design attributes. In this paper we investigate the impact of rules such as attribute aggregation and reference dependency on the mean and the standard deviation parameters to produce revised preference profiles for specific design attributes, as we vary the dimensionality of an SC design. By contrasting mixed logit models with and without IPS conditioning, we are able to establish the extent of parameter shift and the implications on outputs such as willingness to pay. The empirical evidence, drawn from a study in Sydney of car commuter route choice, suggests that accounting for the way that stated choice designs are processed, given their dimensionality, does make a statistically significant difference on the profile of preferences for specific attributes and alternatives. This evidence has value in guiding the design of SC experiments and in adjusting results from different SC designs when comparing the evidence. 2005-01-01T00:00:00Z https://hdl.handle.net/2123/19535 Efficiency and Sample Size Requirements for Stated Choice Studies Bliemer, Michiel CJ; Rose, John M Stated choice (SC) experiments represent the dominant data paradigm in the study of behavioral responses of individuals, households as well as other organizations, yet little is known about the sample size requirements for models estimated from such data. Current sampling theory does not adequately address the issue and hence researchers have had to resort to simple rules of thumb or ignore the issue and collect samples of arbitrary size, hoping that the sample is sufficiently large enough to produce reliable parameter estimates. In this paper, we demonstrate how to generate efficient designs (based on D-efficiency and a newly proposed sample size S-efficiency measure) using prior parameter values to estimate multinomial logit models containing both generic and alternative-specific parameters. Sample size requirements for such designs in SC studies are investigated. In a numerical case study is shown that a D-efficient and even more an Sefficient design needs a (much) smaller sample size than a random orthogonal design. Furthermore, it is shown that wide level range has a significant positive influence on the efficiency of the design and therefore on the reliability of the parameter estimates. 2005-04-01T00:00:00Z https://hdl.handle.net/2123/19448 Constructing Efficient Choice Experiments Rose, John M; Bliemer, Michiel C. J. Research on the construction of efficient designs for stated choice (SC) experiments has been limited to either unlabeled experiments with generic parameter estimates or labeled experiments with alternative specific parameter estimates. Designs combining both generic and alternative specific parameters have not yet been addressed. In this paper, by deriving the asymptotic (co)variance matrix for the most general MNL model, the authors are able to demonstrate how efficient experiments that allow for the estimation of both types of estimates may be generated. The authors go onto show how estimation of the asymptotic (co)variance matrix may also be used to determine sample size requirements for SC experiments. 2011-05-27T00:00:00Z https://hdl.handle.net/2123/19282 Competitive tendering as a contracting mechanism for subsidising transportation: The bus experience Hensher, David A.; Wallis, Ian P. Competitive tendering (CT) is a popular mechanism for the provision of transport services where a major objective is the containment of the cost to government of service provision. Although the primary focus is recognised as cost efficiency, whereby the cost outcome should be conditional on a given level of service, difficulties in establishing appropriate tests for service level compliance has become a cause of concern about the effectiveness of the CT paradigm as a value for money initiative. While recognizing the growing evidence that competitive tendering can reduce levels of subsidy, typically in the 20-30% range, what is lacking in the support is an explicit statement that such gains are usually a windfall gain when first introducing CT, and especially when the incumbent is a public supplier (or a public operator almost exclusively dependent on government funding), and that financial gains through retendering are notably absent. Furthermore the risk of discouraging investment back into the provision of services because of uncertainty of continuity is starting to show up as incentive-incompatible and a discouragement to quality operators who would in the normal course of business reinvest much more. This has led to a growing interest in and support for performance based contracts (PBCs) in which the incentive structure is more conducive to the growing the business (under a trusting partnership between the regulator and the operator) and where CT is a last resort noncompliance strategy. This paper reviews the international successes and failure of CT as a subsidy reduction strategy within the bus sector, and promotes the idea of PBCs as a way of recognizing the real role of subsidy under the umbrella of a value for money objective. 2005-09-01T00:00:00Z https://hdl.handle.net/2123/19236 Evaluation of Different Approaches for the Truckload Vehicle Routing Problem in a Competitive Environment Figliozzi, Miguel Andres The principal focus of this research is to evaluate the effectiveness of different approaches for the vehicle routing problem in a competitive environment (VRPCE). This paper focuses on the study of the VRPCE in a marketplace with time-sensitive truckload pickup-and-delivery requests. In this paper, two carriers compete for service requests; each arriving service request triggers an auction where carriers compete with each other to win the right of servicing the load. This paper will show how the efficiency of routing and costing approaches in different market settings will depend on these carriers’ approaches. A simulation framework is used to evaluate different strategies. Some results and the overall simulation framework are also discussed 2005-06-01T00:00:00Z https://hdl.handle.net/2123/19238 Travel Behaviour of Seniors in an Aging Population: An Exploratory Study of Trip Chains and Modal Preferences in the Greater Metropolitan Area of Sydney Alsnih, Rahaf; Hensher, David A Three concurrent demographic shifts, the aging of the population, and increase in incomes and an increase in health of senior citizens, are likely to cause significant changes to travel demand structures. An increasing proportion of the population will have both relatively high levels of free time which afford the opportunity to undertake a range of activities and the financial and physical capability to carry out these activities. Hence, it is essential to understand how demand for private and public transport may evolve with respect to these fundamental demographic changes. This paper utilises travel demand data to examine this issue, highlighting the likelihood that, as the population continues to age, traffic demand is likely to increase across times of day, impacting the population as a whole through increases in the scope and scale of traffic congestion. A healthy, relatively older and relatively wealthy population is shown to be likely to continue its reliance on the private vehicle, contrary to a traditional belief that, as people age, their demand for travel wanes, along with their personal use of automobiles relative to the use of public transport. 2005-09-01T00:00:00Z https://hdl.handle.net/2123/19241 Route choice behavior of freeway travelers under realtime traffic information provision–application of the best route and the habitual route choice mechanisms Jou, Rong-Chang; Hensher, David A; Chen, Ke-Hung The route choice behaviour on freeways between Taipei and Taichung in Taiwan under real-time traffic information provision is investigated. Two types of route choice mechanisms (the best-route and habitual-route) are analysed using ordered probit models to identify the major influences on freeway travellers’ route choice behaviour. The level of service associated with each route is defined as a generalized cost saving and specified non-linearly with a spline-like threshold inherent to travellers. The marginal (dis)utility thresholds in the ‘best’ and ‘habitual’ behaviour models are identified through a grid search assessed on overall goodness of fit. The findings from this study provide a better understanding of the effects of Advanced Traveller Information Systems on drivers’ route choice behaviour, and a useful reference when planning for the provision of realtime information for drivers. 2005-12-01T00:00:00Z