Hi Boram,

You may want to use vehicle-km instead of passenger-km for the Activity Level variable since you know the number of vehicles. You will need to make an assumption on the annual vehicle-km per vehicle in order to calculate total vehicle-km. A quick Google search revealed a few sources with information on annual vehicle-distance per vehicle that may help get you started(disclaimer: I haven't read these sources in detail):

• https://www.afdc.energy.gov/data/10309
• https://www.eea.europa.eu/data-and-maps/data/external/annual-distance-travelled-by-cars
• https://www.researchgate.net/publication/281020242_Car_Annual_Vehicle_Kilometer_Travelled_Estimated_from_Car_Manufacturer_Data_-_An_Improved_Method
• https://www.eia.gov/todayinenergy/detail.php?id=26192

You can enter the fuel economy in the final energy intensity variable. Recall that fuel economy is defined as energy consumption per unit of vehicle-distance traveled (or its inverse, in the case of MPG). For example, if you know a vehicle's fuel economy in MPG, then calculate its inverse to find the gallons per mile and enter this value in final energy intensity (you will need to change the units accordingly).

Also, currently the way your branches are set up, the same final energy intensity (or fuel economy) will apply to all car types (i.e. electric cars will have the same fuel economy as diesel vehicles), even though fuel economy usually differs between car types. Instead of using the green-colored Categories with Energy Intensity folder for the branches labeled "Cars" and "Buses", if you were to use the yellow-colored Categories folder instead, you would be able to enter different fuel economies for each vehicle type (note that you can't actually change the property type of the branches, you will have to re-create your entire structure if you choose to implement this suggestion).

Hope this helps!

Emily