I find driving cheaper in the
long run. In other words, with everything considered.
If I were single, yes, I`d say public transport is significantly cheaper... But with a family, it would cost as much to take a round trip to a department store by train as 10 trips by car.
The cost advantages REALLY become clear once you start taking long trips. We visit the relatives every month or so, and a train trip up there would be about 25,000 for the 3 of us - plus whatever else we buy to eat along the way, etc. By car, it`s less than 5000 even if we take the expressway.
Cars do cost to much to own and park if you, say, live in Tokyo and hardly ever leave the city. Parking spaces can run as much as renting an apartment it seems... But most other places and they`re not that bad.
Just filled the car today; 96yen/l for regular, 101/l for premium. At the highest in summer, it was 188/l for regular... And I can`t even remember premium as we certainly couldn`t afford it.