| 摘要 | The fuel consumption for passenger vehicles is determined by sequential or interactive various decisions: the number of cars to own, the type of vehicles to own, the type of motor fuels, the classes and models of vehicles to hold and the demand for fuels which is calculated from kilometers traveled of each vehicle given the previous several choices. Therefore, in order to assess the effects of energy policies on transportation sector, it is necessary to develop the econometric models to analyze the ownership and use pattern of passenger car.
The purpose of this study is to specify the choice models of a passenger car by fuel type and to analyze the effects of the change of relative fuel prices on interfuel substitutions in the passenger vehicle sector. Specially, this study focuses on the effects of the second energy tax reform on interfuel substitutions. The relative price ratios among gasoline, diesel, LPG(liquified petroleum gas) are planned to change to 100:85:50 in July 2007 from 100:47:26 in July 2000.
In this study, we utilize the discrete choice models based on the random utility model to analyze the behavioral choices among mutually exclusive alternatives such as gasoline, diesel, and LPG cars. Conditional logit, nested logit and heteroscedastic logit models are applicable for our study to analyze the effects of changes of the relative fuel-price ratios. In addition, we analyze the effects of household-specific characteristics such as income, age, gender, kilometers traveled on the probabilities of choosing vehicles by fuel type. For this analysis, we use a multinomial logit model. The data and information for this study were collected in a survey of Korea Energy Economics Institute conducted for about 1,800 households in 2004.
Results of the analysis of the multinomial logit model which is utilized to assess the effects of household-specific characteristics are summarized as follows. Firstly, drivers with a large demand of kilometers are more inclined to own diesel or LPG cars than to own gasoline cars. Secondly, drivers who mainly use cars for business purposes are likely to hold diesel cars. Thirdly, female drivers prefer gasoline vehicles to diesel or LPG ones. Finally, drivers with low income are inclined to choice LPG cars in order to lower their variable (energy) costs.
Korean government have carried out the second energy tax reform since 2005 to handle the problem of the first energy tax reform caused a rapid dissemination of diesel cars. Three models including conditional logit, nested logit and heteroscedastic logit are utilized to grasp the impacts of the second tax reform on the choice probabilities of passenger vehicles by fuel type. The major finding of this study is that the second reform decreases the probabilities of choosing diesel cars, but increases the probabilities of holding gasoline and LPG vehicles. In other words, the second reform has an effect on mitigating an explosive increase of diesel cars.
There are a few drawbacks in our study. First of all, the results of our analysis are based on a very simple model structure which consists of only three alternatives - gasoline, diesel, LPG cars - without considering classes and models of vehicles by fuel type. Secondly, we inevitably omit important attributes of choice alternatives (vehicles) such as vehicle price, energy efficiency, interior space and horsepower of each vehicle due to the limited availability of data. |
