Methane (CH₄) is an important greenhouse gas emitted by vehicles. This study provides estimates of emissions of this important and often not well characterized greenhouse gas (GHG) emission related to transportation energy use. It aims to assist urban community planners and policymakers to prioritize and choose implementation strategies for low carbon cities. The paper focuses on emissions of CH₄ from vehicles. Unlike emissions of CO₂, which are relatively easy to estimate, emissions of CH₄ are a function of many complex aspects of combustion dynamics and depend on the type of emission control systems used. In this context, they cannot be derived easily and instead must be determined through the use of published emission factors for each combination of fuel, end-use technology, combustion conditions, and emission control systems. Emissions of CH₄ play a significant role with regards to the relative CO₂⁻equivalent GHG emissions of the use of alternative transportation fuels, in comparison with the use of conventional fuels. By analyzing a database based on literature review this study analyzes all the factors affecting the creation of CH₄ emissions from different vehicle types. Statistical analysis indicated “r” values ranging from 0.10 to 0.85 for all vehicles.