The habit-driven life: Accounting for inertia in departure time choices for commuting trips

This paper aims to explicitly account for the impact of inertia (or habit) on departure time decisions, and explore (1) to what extent departure time is influenced by inertia, (2) what influences individuals’ inertia with respect to departure time decisions, and (3) to what extent it impacts transport policies. We estimate an integrated choice and latent variable (ICLV) model using a stated preference survey for morning car commuters in the Greater Copenhagen Area. We interact the rescheduling components in the Scheduling Model (SM) with the latent variable Inertia. The modelling results show that higher levels of inertia yields higher rescheduling penalties and lower willing to shift departure time. Furthermore, we find that inertia in departure time is influenced by gender, presence of children in the household as well as work type. We test the behavioral responses to demand management policies for segments with different inertia, and find that the least inertial segment showed the highest substitution patterns, while the most inertial segment show the lowest substitution patterns. Finally, we compared the ICLV model to a reference model without inertia, and find that the effects of the demand management strategy is overestimated if inertia is neglected

Individuals' Decisions in the Presence of Multiple Goals

This paper develops new directions on how individuals’ use of multiple goals can be incorporated in econometric model

Molecular characterisation of a Cryptosporidium parvum rhoptry protein candidate related to the rhoptry neck proteins TgRON1 of Toxoplasma gondii and PfASP of Plasmodium falciparum.

Given the lack of knowledge on the rhoptry proteins of Cryptosporidium parvum, we searched for putative members of this protein class in the CryptoDB database using as queries known Toxoplasma gondii rhoptry molecules. We cloned a C. parvum sporozoite cDNA of 4269bp encoding the sushi domain-containing protein cgd8_2530, which shared low amino acid sequence identity, yet a highly conserved domain architecture with the rhoptry neck proteins TgRON1 of T. gondii and PfASP of Plasmodium falciparum. On denaturing and native gels, cgd8_2530 migrated at approximately 150 and 1000 kDa, respectively, suggesting an involvement in a multi-subunit protein complex. Immunoflorescence localised cgd8_2530 to a single, elongated area anterior to sporozoite micronemes and showed protein relocation to the parasite-host cell interface in early epicellular stages. Our data strongly suggest a rhoptry localization for the newly characterised protein, which was therefore renamed C. parvum putative rhoptry pr

Addressing endogeneity in strategic urban mode choice models

Endogeneity is a potential anomaly in econometric models, which may cause inconsistent parameter estimates. Transport models are prone to this problem and applications that properly correct for it are scarce. This paper focuses on how to address this issue in the case of strategic urban mode choice models (i.e., the third stage of classic strategic transport models), possibly the main tool for the assessment of costly transport projects. To address this problem, we propose and validate, for the first time, adequate instruments that may be obtained from data that is already available in this context. The proposed method is implemented using the Control Function approach, which we use to detect and correct for endogeneity in a case study in Valparaiso, Chile. The effects arising from the neglected endogeneity in this case study reflect on an overestimation between 26-49% of the subjective value of time and an underestimation of 33-75% of modal elasticities.ANID, FONDECYT 1191104 Instituto Sistemas Complejos de Ingenieria (ISCI) ANID PIA/BASAL AFB180003 BRT+Centre of Excellence - Volvo Research and Educational Foundation

Empirical Identification in the Mixed Logit Model: Analysing the Effect of Data Richness

Mixed Logit model, Empirical identification, Data richness, Repeated choice tasks,

Accounting for inertia in modal choices: some new evidence using a RP/SP dataset

Inertia, RP/SP dataset, Modal choice, Weighted experiences,

Income, Time Effects and Direct Preferences in a Multimodal Choice Context: Application of Mixed RP/SP Models with Non-Linear Utilities

Transport problems typically involve at least two types of constraints, on income and on time. Therefore, the indirect utility function depends either on the income available after having subtracted the cost of the discrete alternative and on the free time left after having worked and travelled by each competing option. In the typical linear-in-the-attributes and in-the-parameters specification, that represents the first grade approximation of the indirect utility function, the effect of income and time constraints cancel out and only the cost and time of the alternatives matter in the comparison between them. From a microeconomic point of view this is equivalent to assume that income and time effects could be disregarded; which is not always the case. To account for these effects the utility function should include second order attributes; however, in non-linear utility functions it may not be easy to distinguish among several effects that could be relevant: direct preferences for good and leisure, and simple interactions between attributes other than income and time effects. This paper analyses these effects from a theoretical point of view focusing on the possible confounding problem in detecting income and time effects. We use a dataset collected for a modal choice context and containing both revealed and stated preference data, and estimate several NL models examining the effect of the different second-order terms on detecting income and time effects. We compared specifications including square cost and time attributes, interactions between time and cost, cost divided by the income available to be spent on free time, and time multiplied by free time. Our results confirm the strong effect of direct preferences for goods and leisure time on choice, and the potential confounding effect between quadratic attributes and other non-linear omitted terms. Finally, we also found that care should be taken in highlighting income and time effects using mixed data sources, since confounding effects can occur when non-linearities are accounted for in both data sets. Copyright Springer Science + Business Media, LLC 2006Income and time effects, RP/SP data, Non-linearities,

On the Treatment of Repeated Observations in Panel Data: Efficiency of Mixed Logit Parameter Estimates

Panel data with repeated observations, Discrete choice models, Parameter efficiency,