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Portland is a PR machine for light rail & streetcar

Here are Some Facts About Portland Oregon          

“It must always be remembered how cost-effectiveness works in the public sector: the cost IS the benefit.” - author unknown





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