The part you're missing: All the people whose public transit you funded aren't driving! It reduced traffic! You benefitted from it, whether you realize it or not. People in the cities pay lots of car and gas-related taxes, despite not owning a car - same thing. That street goes both ways. They fund streets and highways and infrastructure in your area just like you fund public transit in theirs. It's mutually beneficial, even though both parties are funding stuff they may not use.