The distance is 16.2 kms, maybe 3-5$ in gas and 23 minutes travel time (google maps) for 40-45$, that does seem expensive, never really looked too deeply into cab costs. Throw in 5$ for maintenance costs on vehicle (average) and still doesn't come to 10$.
I want to pay for time I'm in vehicle, not the time he's waiting for a fare, I guess it doesn't work that way though.
With the price of gas these days, a moderately fuel efficient car should be able to travel at least 100 kms on $10 of fuel.

