For now, let's focus on Passenger Travel and Energy Use, please look at the 3 middle columns starting with the one just to the left of the Energy intensities header, labeled: Load factor. The relationship between these columns is mathematical. The 3rd column is the middle column divided by the 1st column. Three facts emerge:
- The energy intensity of typical passenger car travel in this country is 3,447 BTUs per passenger mile.
- The average load factor for passenger car travel is 1.55 persons per vehicle.
- Discounting motorcycles for safety reasons, the least energy intense means of passenger travel is rail. Rail has an aggregate average energy intensity of 2,590 BTUs per passenger mile with a load factor of 25.6 persons per vehicle. The most efficient rail service is Intercity (Amtrak) at 2,271 BTUs per passenger mile.
When one travels in a car with three people in it, the energy intensity of that trip drops to 1781 BTUs per passenger mile. That most efficient, average loaded Amtrak train uses 28% more energy than a typical car with three people in it.
Look at commuter rail.
Look at commuter rail.
- How many passengers do you need to carry in your car before your trip is less energy intensive than a trip on commuter rail? (Assume your rail trip will be at average commuter rail passenger load factor.)
- Will extending the tracks improve the load factor of commuter rail? (I don't know if there is a categorical answer to this question.)
- If the average car seats 5, what is the lowest energy intensity obtainable with that average car?
This appendix, from the same source document, shows variation in the energy efficiency of rail choices based on geographic location of the service:
