APTA then compares the average monthly transit fare to the average cost of driving. The cost of driving is calculated using the 2017 AAA average cost of driving formula. That formula is based on variable and fixed costs. The variable costs include the cost of gas, maintenance and tires. The fixed costs include insurance, license registration, depreciation and finance charges. The comparison also uses the average mileage of a mid-size auto at 23.1 miles per gallon and the current price for self-serve regular unleaded gasoline as recorded by AAA each month. The analysis also assumes that a person will drive an average of 15,000 miles per year. The savings is based on the assumption that a person in a two-person household lives with one less car.
In determining the cost of parking, APTA uses the data from the most recent available Colliers International Parking Rate Study for monthly unreserved parking rates for the United States which is the most recent report available.
To calculate your individual savings, with or without car ownership, go to www.publictransportation.org.