"A person can achieve an average annual savings of $8,368 per year by taking public transportation instead of driving, based on today’s gas prices and the average unreserved parking rate, according to the American Public Transportation Association’s (APTA) “Transit Savings Report.”
APTA’s monthly “Transit Savings Report” shows how much a person can save on a monthly or yearly basis by taking public transportation and living with one fewer car in his or her household.
The report reminds commuters that taking public transportation is the quickest way to save money compared with the overall driving costs of commuting by auto or light truck.
Even with gas prices $1.378 lower than last year, the report calculates the monthly savings for public transit users at $697 per month based on today’s gas price of $1.727 as reported by AAA.
The report shows the average annual savings represents almost one-third more than the average amount a household pays for food in a year ($6,111), according to the Food Institute."
The cities that were used in the study are all located in the USA. It appears that there still a substantial saves when using an inter-city transit such as Go Transit. You can go to the APTA calculator in order to figure your savings by riding public transportation.