The objective of this paper was study guidelines for taxation to promote the use of energy efficient passenger cars. The passenger car taxation of 4 developed countries; namely Japan Germany United Kingdom (UK) and United States (US) were analyzed and compared with Thai taxation. And studied barriers for promote the use of energy efficient passenger cars in Thailand. This survey conducted by using the close-ended questionnaires collecting data from 400 people who used passenger cars in Bangkok. The results found that tax on acquisition in the developed countries were only subjected to sales tax while Thailand’s acquisition tax composed of customs duty excise duty municipal tax and value added tax. The ownership tax rates of passenger cars in Japan Germany and UK were based on different fuel consumption parameters such as cylinder capacity vehicle weight and CO2 emissions which can promote energy efficient cars. On the contrary the ownership tax rate of USA and Thailand reduces with the age of vehicle. Fuel tax was imposed to support the country energy policy. Opinion survey results of barriers for promoting energy efficient passenger cars in Thailand showed that the significant problems were the lack of incentives measures to promote the use of energy efficient cars.

Nowadays energy conservation is widely recognized due to fuel crisis. Petroleum is one of the primary energy used in various aspects especially by factories which consume energy at very high rate. Air pollution has been caused for this reason. Lots of industrial sectors have paid attention to this problem and have found out in different ways to manage it. The purpose of this work was to apply compressed air energy which is zero emission energy as an alternative energy instead of fossil energy. This energy was used in a prototype small three-wheeler powered by an impact wrench. The vehicle carried two tanks of 10 liters of air which pressure is 90 bars. The three-wheeler used chains and gears to transmit power to wheels. The gear increased torque ratio of the impact wrench. An air valve was controlled by a sling-controlling lever. On rear wheel hub 3-speed gear was fitted to enable the car move conveniently according to speed of motor and road condition. Test results showed that air car could move with the maximum speed of 21.4 km/hr and the farthest distance of 1917 meters. The longest period of time which the car could move was about 5-6 minutes. The highest torque produced by impact wrench was 2.323 Nm at rotating speed of 3400 rpm. It was also found that between the rotating speed of 2000 and 4000 rpm the impact wrench produced the best performance and this is a good condition to be chosen for further research and development for maximum efficiency.