Do you ever get the feeling that the taxi you took didn’t go the shortest route? Sure it could be because of traffic or road work, but you still wonder if he’s taking a longer road than necessary. And why wouldn’t you? The driver gets paid by kilometer after all!
The idea would be to have an app that you start when the taxi starts, and then stop when you’ve arrived at the location. It would then plot out the route on a map, with some stats as time taken and lenght “driven”. It would also plot out the Google Map route so you can compare.