Singapore has solved this problem, with a little assistance from satellite technology. Imagine Walrasian taxi markets. The taxi driver receives a satellite message on his little thingie, specifying where the customer wishes to be picked up and where he wishes to go. The cabbie, if interested, then enters a bid for how much he will charge. The customer is matched with the cabbie who enters the lowest bid. Amazing, no? And if it is raining, you have the ability to pay more to actually get a taxi.
This is for real (i.e., I saw it twice), but alas I cannot find anything through Google. It is called CanBid, at least on the little machine thingies in the cabs. I’ve opened up comments in case you know more than I do.
They also price the roads, I might add, using electronic sensors. Privacy is no issue, since you don’t have any privacy here anyway.
You should consider this place for your next vacation. I came for work, but I have been consistently charmed and delighted.