The Impact of Automobile Diffusion on the Income Elasticity of Motor Fuel Demand

Abstract

Prompted by the recent surge in light oil product consumption, this paper analyses the demand for non-commercial motor fuel and proposes a long-run forecasting model. In doing so, our aim is to be able to reproduce a few key stylized facts observed in secular evolutions of the motor fuel intensity of GDP and related notably to the derived nature of oil demand. Using a database covering 77 countries over the 1986-1998 period, we explain sequentially the stock of private vehicles per capita and fuel consumption per vehicle. The former is expressed as an S-shaped function of real per-capita income, which takes into account the dynamics specific to the dissemination of a durable good in a population. By explicitly considering the distinct phases of the development of the automobile market, our approach enables us to propose an explanation to the space-time variability in long-run income elasticities reported in the literature - especially its decline as per-capita income increases and the resulting gap between elasticities in emerging countries compared to developed countries. Our two-equation model also enables us to reproduce the “bell” shaped curve of the motor fuel intensity of GDP as a function of per-capita income, as well as the other principal properties of resource intensity-of-use linked to the process of dematerialization which, for any country, follows the industrialization period.