Like most other Green Wheelers I'm concerned about the many negative impacts of motorized transportation and am working to promote and use better alternatives.

For many years I've been working to make lower impact transportation choices. In recent years I've been doing research to quantify the impact of each transportation choice.

As my New Year's resolution for 2007 I decided to keep a personal motorized transportation log. My goals are to:

• Quantify my impacts (greenhouse gas emissions and fuel consumption),
• Look back trip by trip to see how I can make better choices
• Develop better habits
• Make better choices before each trip

For each trip I enter a line with the following information:

• Date of Trip
• Distance
• Number of passengers (for private vehicles)
• Purpose of trip
• Approximate MPG or per-passenger MPG of vehicle

I also created a spreadsheet for entering all the log information and doing calculations.

For instance, on January 1 I took a bus trip from Phoenix to Arcata:

Date of Trip: 1/1/07
Distance: 1200 miles
Number of passengers: not applicable
Purpose of trip: return from Phoenix
Passenger-miles per gallon: 120

Using these figures I calculate 10 gallons of fuel per passenger and using 20 lb of CO2 per gallon gives 200 lb of CO2. For air travel you should multiply this by 2.5 to include the extra impact of emissions at the altitude that jets fly.

On Mach 10 I went on a hike near Honeydew:

Date of Trip: 3/10/07
Distance: 110 miles
Number of passengers: 3
Purpose of trip: hiking
Miles per gallon: 50

Using these figures I calculate 0.73 gallons of fuel per passenger and using 20 lb of CO2 per gallon gives 14.6 lb of CO2.

I project that my total per-passenger fuel use for 2007 will be about 40 gallons. My CO2 generation will be about 800 pounds. U.S. average for personal transportation energy use is about 20,000 pounds per year so my personal use is less than 4% of U.S. average. I estimate that back in 1974 my personal transportation CO2 emissions were about 40,000 pounds per year.

The biggest changes that I made (in order of impact) since 1974 were:

• Stop flying
• Live close to work
• Higher mpg car
• Take public transportation
• Bicycle
• Carpool

Airplanes and single-passenger cars are quick and convenient and don't take very much planning. Alternatives are slower, less convenient and take more advance planning.

Making the changes that I made over the past 30 years took awareness, information and willingness to put doing the right thing rather than what is the easiest and the most convenient. Keeping a personal transportation log can be a tool to make those changes in your life.

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Note: Michael shared an interesting way of looking at his fuel usage, by getting a very rough idea of its equivalence in the amount of land that would be necessary to grow an equal quantity of calories worth of biomass as the calories in the gallons of fuel he burns.

 

Here's what he's found:

I did a very quick back-of-the envelope calculation.
Assuming that my personal share of transportation energy is 40 gallons per year.

1 gallon of gasoline = 125,000 BTU

(40 gallons/year) X (125,000 BTU/gallon) = 5 X 10^6 BTU/year = 1.26 X 10^6 kcal/year (commonly called simply "calories)

(1.26 X 10^6 kcal/year)/(365 days/year) = 3450 kcal/day

3450 kcal is slightly more than I eat per day.

So, even at the incredibly low figure of 40 gallons of gasoline consumed per year, Michael's energy usage in gasoline is equivalent to the amount of food he eats over the year in calories. How this translates to land use equivalence is difficult to do, since many crops and parts of plants that are used to produce biofuels are different from what we eat, but it gives an idea of the energy intensivity of motorized transportation and the of the amount of biomass energy necessary to create fuel for vehicles.

Attached is a copy of the spreadsheet Michael has used to calculate person miles per gallon and gasoline usage.