Life in the big city is not easy, but you know that you should be fare as that is the right thing to do. Besides, every cop in town would be looking for you if you are sleezy. For an honest taxi driver to make a living, he needs to meet more than his boundary.
In this game, you need to meet the requirement of each level to make some progress. Usually, it has something to do with picking up customers and delivering them to their destination. Sounds easy, but that won't be easy since there are rules on the road that you need to follow. Also remember to go to the gas station before you run out of gas. if you didn't then you need to pay more than what is needed.