Taxis in China can be a challenge. Fare is obviously a function of distance and going rate/km. And when you know neither...

And then there's the issue of 'the scenic route' and plain old 'geographically challenged' drivers.

If you can get a heads up on what the price should be, great - otherwise stick with a metered taxi. In such situations I tend to find women drivers by far the best option - not likely to smoke you out of the car, there's evidence they've got a least a modicum of self-preservation, and they're generally more honest.