Released around the turn of the milennium on the Dreamcast (and in Japanese arcades), TBG - developed by Fortyfive (who made Swat Kats on the SNES!) - had you get behind the wheel of one of the Japanese capital's metropolitan buses. And it was serious about it.
While theoritically giving the player more flexibility than train sims, given you're on the road, its guidelines were just as rigid: stray from the road or fail to obey even minor traffic conditions and that was it.
Gameplay was thus resigned to...driving a bus. Slowly, and stopping at a lot of red lights, with missions lasting up to twenty minutes at a turn.
Don't get too judgemental. While it looks and sounds boring as hell, there's a hardcore market for this kind of simulation. Why? Remember: not everyone fantasises about being sci-fi solders or sports stars. Some people just like to kick back and pretend they operate public transport.