Econometric guidance for developing UrbanSim models. First lessons from the SustainCity project.

In the context of the SustainCity project (www.sustaincity.eu), three European cities (Brussels, Paris and Zurich) will be modelled using the land use microsimulation platform UrbanSim. This platform relies on various models interacting with each other, to predict long-term urban development. The aim of this paper is to provide some econometric insight into this process. A common set of notation and assumptions are first defined, and the more common model structures (linear regression, multinomial logit, nested logit, mixed MNL and latent variable models) are described in a consistent way. Special treatments and approaches that are required due to the specific nature of the data in this type of applications (i.e. involving very large number of alternatives, and often exhibiting endogeneity, correlation, and (pseudo-)panel data properties) will also be discussed. For example, importance sampling, spatial econometrics, Geographically Weighted Regression (GWR) and endogeneity issues will be covered. Applications and specific options of the following models: (i) household location choice model, (ii) jobs location/firmography, (iii) real estate price model, and (iv) land development model, will be demonstrated using examples from the on-going case studies in Brussels, Paris and Zurich. Finally, lessons learnt in relation to the econometric models from these on-going case studies will be summarized.

Measuring educational inequalities:A method and an application to Albania

In this paper, we investigate whether educational inequalities stem rather from differences between families or within families. In a poor economy, schooling is costly for parents and education is likely to be unequally distributed among siblings. Drawing on discrete ordered choice models, we present a simple method to estimate the between and within components of both the explained and unexplained variances of education. For our empirical analysis, we use the LSMS survey conducted in 2002 in Albania. We explain about 40% of the total variance and find that inequalities in education are mainly due to differences between families. Differences within family are lower and far less easily explained.Education, intra-household inequality, random effects ordered Probit models, siblings

Congestion on risky routes with risk adverse drivers

We study the impact of information on risk adverse drivers who maximize their von Neumann and Morgerstern expected utility (rather than minimizing expected travel time). The preferences of the users are described by their utility functions. Beside the (potentially inconsistent) mean variance model used so far in transportation, we consider three other standard utility functions: the mean standard deviation model, and the CARA and CRRA utility functions. We show that maximization of expected utility provides a more general formulation than minimization of expected travel time (the latter case corresponds to the standard Wardrop principle). We illustrate the proposed approach with a simple network which consists in one origin/one destination and two routes in parallel. Total demand is inelastic. Capacity on one route is constant and on the other route it is stochastic, and depends on the states of nature, with two possible values. We assume that all users have the same value of time but that they differ in their risk aversion parameter. Equilibrium travel time then depends on the distribution of risk aversion. We consider two polar information regimes: no information and full information. We study the differential impacts of information according to the level of risk aversion, and compute the social value of information. We introduce a formula to compute the value of information that is the individual willingness to pay for information (or in economic terms, the compensating variation). Moreover, we find that optimal route choice may depend on global factors (and not only on local traffic conditions). This has serious implications on the design of driver information systems. Finally, we study road pricing when users are risk neutral (and minimize the expected travel time) and when users are risk adverse. We compare the level of tolls, as well as the benefits of road pricing with and without taking into account risk aversion.

Risk in Transport investments

We discuss how the standard Cost-Benefit Analysis should be modified in order to take risk (and uncertainty) into account. We propose different approaches used in finance (Value at Risk, Conditional Value at Risk, Downside Risk Measures, and Efficiency Ratio) as useful tools to model the impact of risk in project evaluation. After introducing the concepts, we show how they could be used in CBA and provide some simple examples to illustrate how such concepts can be applied to evaluate the desirability of a new project infrastructure.Cost-Benefit Analysis, Risk, transportation, large project, Value at Risk, Conditional Value at Risk.

Discrete choice models with capacity constraints: an empirical analysis of the housing market of the greater Paris region

Discrete choice models are based on the idea that each user can choose both freely and independently from other users in a given set of alternatives. But this is not the case in several situations. In particular, limitations and interactions can occur when the number of available products of one type is smaller than the total demand for this type. As a consequence, some individuals can be denied their preferred choice. We develop a methodology to address those constraints and we apply it to residential location choice, where our empirical data suggest that availability constraints may bias actual choices. The analysis provides some theoretical developments and elaborates an iterative procedure for estimating demand in the presence of capacity constraints. The empirical application relies on the location choice model developed and estimated in [6] for Ile de France (Paris region) and generalizes it to integrate capacity constraints.Residential location, constrained Logit, capacity constraints, sampling, Ilede- France

Congestion, risk aversion and the value of information

Information about traffic conditions is conveyed to drivers by radio and variable message signs, and more recently available via the Internet and Advanced Traveler Information Systems (ATIS). This has spurred research on how travelers respond to information, how much they are likely to benefit from it and how much they are willing to pay for it. We analyze the decisions of drivers whether to acquire information and which route to take on a simple congested road network. Four information regimes are considered: No information, Free information which is publicly available at no cost, Costly information which is publicly available for a fee, and Private information which is available free to a single individual. We find that Private information is individually more valuable than either Free or Costly information, while the benefits from Free and Costly information cannot be ranked in general. We also find that Free or Costly information can decrease the expected utility of drivers who are sufficiently risk-averse.

Individual and couple decision behavior under risk: Evidence on the dynamics of power balance

This paper reports results of an experiment designed to analyze the link between risky decisions made by couples and risky decisions made separately by each spouse. We estimate both the spouses and the couples' degrees of risk aversion, we assess how the risk preferences of the two spouses aggregate when they make risky decisions and we shed light on the dynamics of the decision process that takes place when couples make risky decisions. We find that, far from being fixed, the balance of power within the household is malleable. In most couples, men have, initially, more decision-making power than women but women who ultimately implement the joint decisions gain more and more power over the course of decision making.Balance of power; Experiments; Household decision-making; Risk.

Individual and Couple Decision Behavior under Risk:The Power of Ultimate Control

This paper reports results of an experiment designed to analyze the link between risky decisions made by couples, and risky decisions made separately by each spouse. We estimate both the individuals and the couples’ degrees of risk aversion, and we analyze how the risk preferences of the two spouses aggregate when they have to perform joint decisions under risk. We show that the man has more decision power than the woman, but the woman’s decision power increases when she has ultimate control over the joint decision.

Risk aversion, the value of information and traffic equilibrium

Information about traffic conditions has traditionally been conveyed to drivers by radio and variable message signs, and more recently via the Internet and Advanced Traveler Information Systems. This has spurred research on how travelers respond to information, how much they are willing to pay for it and how much they are likely to benefit from it collectively. In this paper we analyze the decisions of drivers whether to acquire information and which route to take on a simple congested road network. Drivers vary in their degree of risk aversion with respect to travel time. Four information regimes are considered: No information, Free information which is publicly available at no cost, Costly information which is publicly available for a fee, and Private information which is available free to a single individual. Private information is shown to be individually more valuable than either Free or Costly information, while the benefits from Free and Costly information cannot be ranked in general. Free or Costly information can decrease the expected utility of drivers who are very risk-averse, and with sufficient risk aversion in the population the aggregate compensating variation for information can be negative.Transportation, route choice, information provision, expected utility, congestion

Eliciting Utility for (Non)Expected Utility Preferences Using Invariance Transformations

This paper presents a methodology to determine the preferences of an individual facing risk in the framework of (non)-expected utility theory. When individual preference satisfies a given invariance property, his utility function is solution of a functional equation associated to a specific transformation. Conversely, there exist transformations characterizing any given utility function and its invariance property. More precisely, invariance with respect to two transformations uniquely determines the individual utility function. We provide examples of such transformations for CARA or CRRA utility, but also with any other utility specification and discuss the example of DARA and IRRA specifications.Utility theory; risk aversion, elicitation of preferences.