科研之友
微信
新浪微博
Facebook
分享链接
摘要
Demand systems are widely applied to the energy and fuel demand research as result of growing concerns over climate change and global warming, especially these issues in cities. However, in existing literature on consumer demand, the authors too often ignore the theoretical regularity conditions, or do not report the results of full regularity checks. As a consequence, the duality theory and second-order conditions for optimizing behavior are invalid in face of the real-world problem. And, the conclusions or suggestions proposed based on the empirical researches are thereby inappropriate and even misleading. Driven by the gap between theoretical models and practical problems, we estimate the demand for road passenger transport in China, which is considered to be one of the most important sources of air pollution in city, using three flexible functional forms, the Rotterdam model, the Almost Ideal Demand System (AIDS), and the quadratic AIDS (QUAIDS). We focus on all theoretical regularities (positivity, monotonicity, curvature, adding-up, homogeneity, and symmetry), and argue that unless there is a coincidence, flexible functional forms are subject to certain theoretical regularities, and that all these regularities are equally important both in theory and in practice. Empirical estimation shows that the AIDS model is the only model that is able to provide theoretically consistent estimation of the demand for road passenger transport in China. Our results also imply that the private transportation is elastic in price changes, compared to urban public transportation and intercity public transportation. We bridge the gap between theoretical modelling and empirical research on consumer energy (fuel) demand, especially in the research about consumer demand for energy-intensive products and services. Our study points out a crucially important fact that the researchers and policy makers must pay attention to the regularities of the theoretical modelling in the practical applications.
