Economic development and changes in car ownership patterns.

The contributions of this paper are twofold: On the one hand, the paper analyses the factors determining the growth in car ownership in Spain over the last two decades, and, on the other, the paper provides empirical evidence for a controversial methodological issue. From a methodological point of view, the paper compares the two alternative decision mechanisms used for modelling car ownership: ordered-response versus unordered-response mechanisms. A discrete choice model is estimated at three points in time: 1980, 1990 and 2000. The study concludes that on the basis of forecasting performance, the multinomial logit model and the ordered probit model are almost undistinguishable. As for the empirical results, it can be emphasised that income elasticity is not constant and declines as car ownership increases. Besides, households living in rural areas are less sensitive than those living in urban areas. Car ownership is also sensitive to the quality of public transport for those living in the largest cities. The results also confirmed the existence of a generation effect, which will vanish around the year 2020, a weak life-cycle effect, and a positive effect of employment on the number of cars per household. Finally, the change in the estimated coefficients over time reflects an increase in mobility needs and, consequently, an increase in car ownership.Car ownership, ordered probit model, multinomial logit model.

Cross-section data, disequilibrium situations and estimated coefficients: evidence from car ownership demand

The objective of this paper is to analyse to what extent the use of cross-section data will distort the estimated elasticities for car ownership demand when the observed variables do not correspond to a state equilibrium for some individuals in the sample. Our proposal consists of approximating the equilibrium values of the observed variables by constructing a pseudo-panel data set which entails averaging individuals observed at different points of time into cohorts. The results show that individual and aggregate data lead to almost the same value for income elasticity, whereas with respect to working adult elasticity the similarity is less pronounced.Cross-section, Pseudo panel, Disequilibrium.

Traffic forecasts under uncertainty and capacity constraints

Traffic forecasts provide essential input for the appraisal of transport investment projects. However, according to recent empirical evidence, long-term predictions are subject to high levels of uncertainty. This paper quantifies uncertainty in traffic forecasts for the tolled motorway network in Spain. Uncertainty is quantified in the form of a confidence interval for the traffic forecast that includes both model uncertainty and input uncertainty. We apply a stochastic simulation process based on bootstrapping techniques. Furthermore, the paper proposes a new methodology to account for capacity constraints in long-term traffic forecasts. Specifically, we suggest a dynamic model in which the speed of adjustment is related to the ratio between the actual traffic flow and the maximum capacity of the motorway. This methodology is applied to a specific public policy that consists of suppressing the toll on a certain motorway section before the concession expires.

La política de las coaliciones en Cataluña

En este trabajo se analizan las diferentes características de los gobiernos autonómicos de Cataluña, todos ellos de coalición. La atención se centra, especialmente, en analizar los efectos que tienen los gobiernos de coalición sobre tres grandes ámbitos: el rendimiento electoral, la distribución intracoalicional del poder y el rendimiento intergubernamental

Hedonic prices for cars: an application to the Spanish car market, 1981-2005

In this paper we provide a comparison of different formulations for hedonic regression analysis in order to construct a quality-adjusted price index for the Spanish car market over the period 1981-2005. Specifically, we address the issue of instability of coefficients over time, and propose two alternative estimation procedures based, firstly, on a moving sample of observations and, secondly, on a moving average of estimated coefficients in single period equations. The statistical tests applied support the proposed methodologies. On empirical grounds two conclusions can be emphasised. Firstly, our study concludes that, taking quality changes into account, car prices in Spain deflated by CPI declined by 40% between 1981 and 2005. This result is robust to the alternative estimation procedures employed in the study. Secondly, an analysis of sigma-convergence shows that for quality-adjusted prices a clear trend in σ-convergence emerges between 1986 and 1992, whereas such a trend does not exists for observed prices. This result has to be related to Spain’s integration into the European Comunity