This book present a new method for calculating motorcycle emission base on global possition system data. This toolbox uses GPS data which was collected from motorcycle usage activities. The data was then used as inputs into the toolbox for calculating precisely the total amount of emissions as well as the amounts from each type of emissions such as CO, CO2, HC, NOx, etc. On the other hand, the understanding of other factors which affect emissions from motorcycles is also very important for attaining suitable emission control policies. Thus, another purpose of this study is to discover these factors by combining the GPS information with results from the household travel survey (which includes household/individual, socio-economic information as well as household members' trip diaries). To do this, we employ the multilevel modeling method.