Main countries set up the method and follow the way that IPCC proposes in each GHG statistical method to get base-line of transportation sector. Main country or organization proposes decrement method in transportation sector based on the premise that it meets transportation demand and transportation safety, the main goal improves the efficiency of the fuel, uses low GHG emission fuels, reduces vehicle traveling mileages, combines economic inducement and offer, to slow down the growth. Using Taiwan energy#s balance table as principle to assess the emission of GHG in transportation sector, the result is 37,885 Gg CO2 eq in 2003. Predicted emission of GHG in transportation sector will be 57,438 Gg CO2 eq in 2025. 5 meetings and forums were held to distinguish greenhouse gas emission statistical and predicted estimate method of adopting, the dependability and exactness of the data, examine compile manual, and discuss the possible problems after Kyoto Protocol executed.Compared with other countries, the vehicle energy efficiency is still low in Taiwan. To reduce transport activity, and to use clean masses transport system are important tasks. More decrement measures should be considered. Based on the conclusion of national energy meeting (2005), decrement goal in transportation sector can roughly reach the energy-conserving goal of 2015 years and CO2 decrement goal of 2010 years, but it is still unable to reach the target emission for 2020 and 2025 years. To accomplish the reduction amount for year 2025, it needs to execute more forced controlling measures. The total emission index, the average quantity index, and the regenerated energy rate of utilization index are proposed for the decrement index.

greenhouse gas,transportation section,decrement measures