2.3.3. Travel Behavior and GHG Emissions

The variables used in analyzing travel emissions were annual per capita transportation emissions from local, domestic, and international travel. The GHG emissions were taken from the previous study of Czepkiewicz et al. [15]. They used a broad life cycle assessment (LCA) approach, accounting for both direct and indirect emissions, such as those from direct combustion, fuel and electricity production, transport infrastructure construction, and vehicle manufacturing and maintenance [15].

A large number of respondents reported zero emissions from either local, domestic, or international travel. Binary variables signifying participation or non-participation in each type of travel were computed. For those that participated in travel, the natural logarithm of emissions was used to normalize the data.
