Ideas for Car-Pooling

While commuting to office, I was seeing people calling and then checking where their friends or office cabs are coming. This involves so much of talking. So idea was formed. We could technologically form groups and then based on the location of the friends on the car, the locations are shared and then the person exactly knows how long it would take for the cab to reach the location and then exactly wait. this would really solve the issue of constantly thinking have i really missed the cab, or is the cab late, what would be the average time to reach to the location. Only thing is that this would make those people who lie about their location would be in soup. I want to work on this idea and build atleast the basic framework so that it can be shared in Google Apps.