Impact of within family negotiation on mobility choices
The study of short-term mobility decisions (daily commutes) and of the long-term mobility decisions (residential location and workplace) allowed us to highlight the role of bargaining within the household. We analyzed and estimated the interdependence of the choices made by the different household members to explain the final decisions as a result of an intra-family negotiation process. <br />Our first set of results focuses on the commuting behaviour of spouses competing for the use of the household vehicle(s). Our second set of results concerns the residential location of spouses; they show that it is the result of compromises between spouses when they have workplaces far apart from each other. In both cases, taking the negotiation into account corrects the bias in the measurement of the value of time, a key element in the Cost-Benefit Analysis. Our work demonstrates the impact of circumstances (being together or alone) on the value of time. Finally, we evaluated the impacts of public policies on residential location choices by analysing the role of capacity or credit constraints, as well as of social mix.
We developed an original methodology combining survey data and census data to build different models. These can be used to estimate the value of time based on individual characteristics, on mode choice (private vehicle vs public transport), on comfort level and on the context. They also make it possible to estimate the costs of early or late arrivals. We have designed nested discrete choice models to analyse decision trees concerning the purchase or rental of housing, the choice of the type of dwelling (apartment vs house) and of the place of residence. These models integrate the trade-offs between housing prices, access to services and public infrastructures, social mix and travel time of each spouse. They also include capacity constraints (housing supply does not adjust to household demand) or access to credit. Our methodology also makes it possible to analyse the decisions of spouses when their preferences or constraints diverge, based on negotiation models adjusted to the family context.
Several websites highlight our work: Elitisme.fr (showcase for academics), Riskdynametrics.com (survey available to the general public, to students and to Professors), Metropolis.elitisme.fr (application to test public transport policies, which will be addressed eventually to a large audience). The models obtained are designed to feed urban simulation models (UrbanSim) or traffic models (METROPOLIS). Discussions are ongoing with the software editors, the Société du Grand Paris, La Poste and the Ministry of Ecology, to explore some potential partnerships.
The ELITISME project has established a new modeling method that can be adapted to a multitude of questions in family economics and other areas, when a decision is taken jointly by several household members. Public policy evaluation results were presented and discussed with a wide audience, not only academics, but also representatives of public authorities, with a view to jointly developing simulation models and other operational tools allowing policyholders to decisions to improve their assessment of public policies or and major investment projects.
The results of this project highlight the drawbacks of the simplifications commonly used in modeling household behavior and their detrimental effects on the conclusions of transport models and more generally on the evaluation of public policies. The work carried out proposes more realistic alternative models of the decision-making process within couples.
In this project, we have published 15 articles, a book and a special issue promoting ELITISME conference organized in the honour of Nobel Laureate D. McFadden. The final conference brought together specialists (family economics, geography, urban and regional economics, game theory and econometrics) and public decision-makers. Our work allowed to promote to the scientific community and to the civil society innovative methods to model household behaviour.
Our general purpose is to analyze decisions related to mode choice and residential location, with a special emphasis on within-family decision process and on policy implications. Our approach extends the current literature by explicitly recognizing that the decisions of different family members are interrelated and we describe them as the outcome of a within-family bargaining process. On the one hand, this project will provide a new application field to family economics, and on the other hand, urban and transportation economics will benefit from economic literature on bargaining and collective decisions, largely ignored till now, with a few exceptions by some consortium members.
In Part 1, we model spouses’ joint mode choice for commuting trips. The interaction is due to the fact that spouses may share a single car, or may carpool. As such, the choice of the car (or of who is driving it if it is shared) is described as the outcome of a bargaining process.
In Part 2, we study residential location choices, which are the outcome of a subtle compromise when the two spouses work at different places, extending up to a three-stage nested Logit model. More precisely, we will model tenure choice, residential location choice and workplace choices, in the context of hierarchical nested models, including the (Pareto) weights of each spouse. The research combines stated preferences (using survey and experimental economics data), and revealed preferences (using census data for the Paris-Ile-de-France Region).
In Part 3, we investigate the effect of public urban policies on household residential location choices by extending Part 2 models to investigate the effects of (1) capacity constraint (when prices do not clear the market and supply is lower than demand in some places); and (2) credit constraints on household tenure and location choices. Credit constraints either refrain households from buying some apartment or house, or induce them to move far enough from the city center (and often far from their job location) in order to find an affordable housing. These financial constraints are based on household income and other characteristics, and affect household joint residential decisions.
The project is coordinated by University of Cergy-Pontoise (UCP), which has established a tradition in transportation and urban economics, and associates ENS-Cachan, with researchers specialized in discrete choice models and public policies, and Ecole Polytechnique, who plays a major role in the management of large data sources, and in data collection. This mix of resources and knowledge is crucial to attain the purpose of this interdisciplinary project.
This collaborative project involving scholars in France, Europe, USA and Australia builds on the results of two previous projects coordinated scientifically by ENS-Cachan, for the first one and by UCP, for the second one. (1) In SustainCity, a collaborative PF7 European project (with 12 partners), a European Land Use and Transport Integrated (LUTI) model was developed and applied by UCP to Paris Region. (2) In the French Predit project MobMen, an interactive survey (MIMéTTIC, Mobilité Individuelle, mobilité des Ménages, Tarification des Transports Individuels et Collectifs) was administered. UCP elaborated an innovative protocol and collected individual data (4,000 respondents, including 1,000 couples). This unique dataset provides the information required to build mobility family decision models. Given the innovative dimension of this project, such data based was required for the development of realistic couple decision models. Other data will be used: The French General Population Census, and the data collected with on-line questionnaires and in experimental economics laboratories.
The medium and long-term social and economic implications of several policies will be analyzed, such as: tolling, zoning, regulation, provision of infrastructure or provision of social housing.
Madame Nathalie Picard (THéorie Economique Modélisation et Application)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
PREG-CECO Ecole Polytechnique
THEMA THéorie Economique Modélisation et Application
Help of the ANR 385,564 euros
Beginning and duration of the scientific project: September 2014 - 36 Months