In much of the world, compressed natural gas (CNG) has been a long recognized alternative transportation fuel due to the fact that it is domestic, one of the cleanest burning and most affordable alternative transportation fuel available - directly addressing three key issues of the countries: national security, global warming & air quality and the economy. However, due to the complex adoption dynamics and diffusion processes, most endeavors to introduce and build sustainable demand for natural gas vehicles (NGVs) have been underachieved. This paper analyzes a wide range of policies to promote natural gas vehicles in new as well as in mature markets. In this paper, several success and failure factors for the introduction of natural gas vehicles (NGVs) are examined and compare the government policies for the adoption of natural gas vehicles (NGVs) throughout the world but majorly concentrated on twelve countries: China, Iran, Pakistan, Argentina, India, Brazil, Thailand, Italy, United States, Germany, Sweden and South Korea. The paper examines the transition road map to CNG technology implantation and identifies lessons that could be useful to developed countries in their efforts to deploy natural gas vehicles.