Yoshihiko Takahashi chuckles politely when asked if he is weary of having the same conversation with passengers every day as he shuttles them around Tokyo in his white and blue all-electric taxi. How often do you have to recharge? How far can you go? Does this car really have no emissions? Those are just some of the queries he has grown used to during his 90-day trial use of three zero-emission taxis, and a designated battery-switch station in the first undertaking of its kind in the world.