"1.) shift change in 15 minutes. So they can take you 15 minutes away but they can't drive an hour into Brooklyn and miss their shift change. 2.) Car maintenance, refueling. If the car is running low on fuel they can pick people up on short drives towards the gas station but it wouldn't make sense for them to go the opposite way."

99% of the time these are not the circumstances when a cab driver attempts a pick-up but refuses when he hears the location.