As in Tokyo, taxi drivers in Hiroshima often know little of their city, but to avoid loss of face before foreigners, will not admit their ignorance, and will accept any destination without concern for how long it may take them to find it.
as 引导的比较从句，省略成分为常态。承前省略或蒙后省略都十分常见，本句就是蒙后省略了重复的成分。
in Tokyo 和 in Hiroshima 是对应的。省略的就是对应之外的成分。完整的表达，其实是不允许的啰嗦表达：
As taxi drivers in Tokyo often know little of their city，
As in Tokyo 是省略造成的结果。as 是比较连词，不是介词，不能说介宾。从句省略成分很正常。
