Recherche

Publications - revues à comité de lecture (en cours de construction)

Sélection de publications dans des revues en Economie :

Abstract

Mobility enables to find jobs, go to school or meet people. However, long distances, high costs, car dependency and poor accessibility are sources of mobility vulnerabilities. The current rise in fuel prices may have a strong impact on mobility, especially for households that rely heavily on their cars. Moreover, the need to reduce air pollution and greenhouse gases emissions requires the implementation of ambitious environmental policies. It is therefore necessary to identify transport poor households, affected by financial issues, as well as vulnerable households whose mobility would be strongly impacted by changes in individual mobility conditions and would have difficulties to adapt to this situation. To this end, we construct VulMob, a multidimensional indicator made up of thirteen individual factors organized in four dimensions: financial resources and transport affordability, work constraints, heavy car use and accessibility and structural constraints. We apply this indicator to the Grenoble area, in France. Our results show that 9.6% are highly vulnerable, meaning that they face at least six vulnerability issues and 5.5% of the households face transport affordability issues. A typology of five profiles of highly vulnerable households shows that some are financially constrained; others are heavy car users, work at night or face public transport accessibility problems. 

Abstract

Using a stated preferences survey, the objective of this paper is to investigate the intra- and inter-individual heterogeneity of mode choice, when travel time is subject to variability. By‘inter-individual heterogeneity’ is meant that people are different in terms of attitude to risk and have different utility functions. By ‘intra-individual heterogeneity’ is meant that the behaviour may be different even when performed by the same individual when faced with a different mode of transport. Based on Rank-Dependent Utility Theory, the paper shows that the occurrence of delays associated with train trips is overestimated whereas they are underestimated for car trips. A latent-class logit model offers a somewhat different perspective: if, overall, car users are more likely to perceive possible delays for train trips than for car trips, train users tend to consider the objective occurrence of delays as they are presented in the survey and adopt a risk neutral choice behaviour. 

Abstract

Based on choice experiments conducted in the Rhône-Alpes Region (France), we estimate an Integrated Choice and Latent Variable model that addresses heterogeneity in values of interurban travel time. We evaluate how sensitivity to travel time by public transport is distributed according to the level of comfort. Comfort is modeled as a function of objective attributes and individual perceptions about it: whether a seat is guaranteed, quality of trip experience (feelings experienced), (perceived) use of travel time during the trip, and overall ease of using public transport (perceived behavioral control). The results show that the last two play a significant role in the choice of a public transport mode and that the value of time function is downward sloping with higher levels of objective and perceived comfort. We discuss public policy implications and show that the most effective measure, in terms of economic benefits, would be to optimize and target investments in seat capacity supply. 


Abstract

This paper considers the recently introduced family of reference models dedicated to non-ordered alternatives. The link function of reference models is that of the multinomial logit model (MNL) replacing the logistic cumulative distribution function (cdf) by other cdfs (e.g., Gumbel, Student). We determine all usual economic outputs (willingness-to-pay, elasticities,...). We also show that the IIA property generally does not hold for this family of models, because of their noninvariance to the alternative chosen as a reference. We estimate and compare five reference models to the MNL on a travel mode-choice survey: according to the chosen cdf, reference models lead to a better fit and retrieve consistent economic outputs estimations even when there is a high unobserved heterogeneity. 

Abstract

Starting from the intuition that people with high environmental concern have a better perception of public transport and therefore a better perception of the utility of public transport, we construct a theoretical model in which the effect of environmental concern on mode choice habits is mediated by the indirect utility of travel. Travel procures the direct utility of providing access to activities, but it also offers an indirect utility that is inherently personal and perceptual. We approach the indirect utility of public transport by measuring perceptions of time and feelings. The indirect utility of the car is approached by measuring affective and symbolic motives. Taking into account car use habits and habits of public transport use, the results show that people who have a high environmental concern perceive public transport use as easier, more useful and more pleasurable than people who do not have that environmental motivation  

Sélection de publications dans des revues pluridisciplinaires :

Abstract

Background

Frequent car use contributes to health and environmental issues such as air pollution, climate change and obesity. Active and sustainable mobility (bike, walk, public transport, car sharing) may address these issues. Different strategies have been implemented in past research, involving hard levers, aimed at modifying the economical or geographical context (e.g., free public transport), and soft levers, aimed at modifying psychological processes (e.g., personalised transport advice). However, few studies have combined both hard and soft levers. In addition, few have used robust methodologies (e.g., randomised controlled trials), followed behavioural changes in the long-term, and been anchored in behaviour change theories. InterMob aims to address these limits by implementing a 24-month randomised controlled trial including hard and soft levers. The objectives of InterMob are to a) evaluate the effectiveness of an experimental arm versus an active controlled arm, and b) identify the processes of mobility change.

Methods

Regular car users living in Grenoble (N = 300) will be recruited and randomised to one of the two arms. The experimental arm consists in a six-month intervention combining hard levers (free access to transport/bikes), and soft levers (e.g., personalised transport advice). The control arm consists in a six-month intervention aimed at raising awareness on air pollution and its health effects. Both arms will include eight evaluation weeks (spread out over 24 months) based on a GPS, an accelerometer, and a pollution sensor. Moreover, participants will complete mobility logbooks and surveys measuring psychological constructs, socio-economical, and socio-spatial characteristics.

Discussion

InterMob will assess the effectiveness of two interventions aimed at reducing car use within regular car users in the short-, mid- and long-term. Moreover, InterMob will allow to better understand the psychological processes of behaviour change, and the socio-economical and geographical conditions under which the intervention is efficient in reducing car use. Finally, the benefits of mobility change in terms of physical activity, quality of life, and exposure to pollution will be quantified.

Abstract

Context

Policies aiming at decreasing air pollutants (e.g., fine particulate matter, PM2.5) are often designed without targeting an explicit health benefit nor carrying out cost-benefit analyses.

Methods

We developed a transdisciplinary backward and forward approach at the conurbation level: from health objectives set by local decision-makers, we estimated which reductions in PM2.5 exposures and emissions would allow to reach them, and identified urban policies leading to these reductions (backward approach). We finally conducted health impact and cost-benefit analyses of these policies (forward approach). The policies were related to the most emitting sectors in the considered area (Grenoble, France), wood heating and transport sectors. The forward approach also considered the health impact and co-benefits of these policies related to changes in physical activity and CO2 emissions.

Findings

Decision-makers set three health targets, corresponding to decreases by 33% to 67% in PM2.5-attributable mortality in 2030, compared to 2016. A decrease by 42% in PM2.5 exposure (from 13.9 µg/m3) was required to reach the decrease by 67% in PM2.5-attributable mortality. For each Euro invested, the total benefit was about 30€ for policies focusing on wood heating, and 1 to 68€ for traffic policies. Acting on a single sector was not enough to attain a 67% decrease in PM2.5-attributable mortality. This target could be achieved by replacing all inefficient wood heating equipment by low-emission pellet stoves and reducing by 36% the traffic of private motorized vehicles. This would require to increase the share of active modes (walking, biking…), inducing increases in physical activity and additional health benefits beyond the initial target. Annual net benefits were between €484 and €629 per capita for policies with report on active modes, compared to between €162 and €270 without.

Conclusions

Urban policies strongly reducing air pollution-attributable mortality can be identified by our approach. Such policies can be cost-efficient.