Startup Idea : Tracking Public Transport Service in Real-time

The idea is to enable travelers/passengers/commuters by providing information about desired bus/train in real-time on their smartphones. With this feature, users would be able to know the location of desired bus/train (where particular bus/train is currently and possibly how long would it take to reach her pick-up point so that user can be sure and well informed about the arrival timings). Building real-time tracking system for each and every bus/train is not scalable solution. So, I am thinking of leveraging smartphones' built-in technologies (e.g., GPS, Internet). As part of solution, we need to install RFID like devices in bus/train. This device can uniquely identify bus/train and its service provider. Other related metadata (e.g., route, timings, etc.) can be stored on server. When user travels via such RFID-enabled bus/train, user's smartphone can post the RFID data along with current location to server and subsequently other commuters will be able to get the latest updates about the bus/train that they wish to catch.