I recently read in the Southwest Journal that there is still some protest against the Southwest LRT line The ironic part of this protest is the attempt to paint the light rail line as being detrimental to the environment, specifically the forest cover in the kenilworth corridor.
The claim was made that “5,000 trees will be lost which will negate any environmental benefits of the line.” I have an engineering background, so I saw an opportunity to do the math. The average tree sequesters 50 pounds of CO2 per year. A gallon of gasoline emits 19.2 lb of CO2 when burned, and we can assume that a car gets around 25 miles per gallon. 5,000 trees will sequester the CO2 emitted by a car traveling for 315,000 miles in a year.
If a commuter drives 10 miles per day 250 miles per year and switches to the light rail line, this is equivelent to 126 person-trips per day on the line. The Green line is projected to have 16,000 trips per day. I’ll leave the rest of the conclusion as an excercise for the reader.