Portland is a PR machine for light rail & streetcar

Here are Some Facts About Portland Oregon

A value of 125,000 (a) is generally used as the heat content of one gallon of gasoline. (138,700 for Diesel)

If one gallon takes you 10 miles, then each mile required 1/10 of a gallon.

Expressed as an equation (Applying rules of fractions to the units):

BTU per gallon

BTU per vehicle-mile = ------------------------------

vehicle-miles per gallon

Next you can adjust for more than one passenger. (The driver of a car is a passenger, the bus driver is not):

BTU per vehicle-mile

BTU per passenger-mile = ------------------------------

passengers per vehicle

For 32 MPG:

125,000 / 32=3,906 per vehicle mile

3,906 / 1.2 passengers = 3,255 BTU per passenger-mile

For 60 MPG:

125,000 / 60 = 2,083 BTU per vehicle mile

2,083 / 2 passengers = 1,042 BTU per passenger-mile

Analysing Trimet's claimed mileage for cars and SUVs:

14 mpg:

125,000 divided by 14 mpg = 8,928 BTU per vehicle-mile. 8,928 / 8,150 = 1.10 passengers

17 mpg:

125,000 divided by 17 mpg = 7,352BTU per vehicle-mile. 7,352 / 6,712 = 1.19 passengers

a. Some sources show gasoline at 123,976 BTU/gal. (this is a difference of about 0.8%)

How to calculate BTU per passenger mile from miles per gallon