中国汽车需求预测:基于Gompertz模型的分析

人均收入水平是影响汽车拥有率的决定性因素.本文在前人研究的基础上,运用Gomp-ertz模型研究汽车拥有率和人均收入之间的非线性关系.本文选取的研究对象既包括当今的发达国家,又包括众多发展中国家,尤其是亚洲的欠发达国家.通过对各国的时间序列数据和多国的横截面数据做回归,并对汽车拥有率及其收入弹性做国际比较,研究发现Gompertz方程能够很好地解释各国汽车拥有率发展共有趋势:在一国经济发展过程中,汽车拥有率先加速增长,在经历了一个拐点后,减速增长,最后无限趋近于共有的餍足点,本文设为0.62;而收入弹性呈先上升,在达到最大值后下降的状态.本文重点分析了近年来中国的汽车拥有率问题,并预测出中国的汽车拥有率拐点在人均GDP YIP=12 000,汽车拥有率VIp=0.2281上,假定中国人均GDP的增长速度在3%-7%的范围内,这个拐点将发生在2015-2042年之间,那时的汽车总量将大于259 996 496辆.此外,收入分配不均对中国的汽车拥有率有着重要的影响.

CAR OWNERSHIP FORECAST IN CHINA--An Analysis Based on Gompertz Equation

Per capita income plays a dominating role in explaining the variation in car ownership. Based on previous studies, this project assesses the nonlinear relationship between car ownership and per capita GDP by using the Gompertz model. The representative countries selected include developed countries as well as a number of developing countries, especially the less developed countries in Asia. This paper examined the time-series regressions of individual countries and cross-section regression of representative countries as a whole. From international comparison of car ownership and income elasticities, this study concludes that the Gompertz function can explain the pattern of car ownership at country level worldwide: as an economy grows over time, the growth of car ownership rises, and after some inflection point, falls. Car ownership ends up being infinitely approaching the common saturation level, which is 0.62 by assumption. Income elasticity first increases, and then decreases after reaching its maximum value. Further, as the major task of the paper, a car ownership forecast of China is carried out. In the case of China, the inflection point is found at the point of per capita income YIP = 12,000 yuan (constant RMB) and car ownership VIP = 0.2281, which is most likely to occur during the year 2015 to 2042 assuming a range of 7% to 3% average per capita GDP growth rate, and at this point, the car stock will be more than 259,996,496. In addition, income inequality has a significant effect on car ow nership in China.