Application for iPhone/Android to request taxi

Please read carefully. We are looking to create an app for Android and iPhone, that would work as follows: The app is for people interested in taxi services. Upon download, people will be requested to enter their information: name, telephone number, among others. Then they would be taken to the app's main page, which would be a map of the user's area, with a dot indicating the user's location. At the bottom of the screen there would be a button saying "Request taxi". Whenever the user wants a taxi to come, they would tap that button. That would send the user's information and location to our central web system. Our affiliated taxi drivers would have a different version of the app on their smartphones. They would also have to enter their information, and would at any moment have the option to register themselves as "taken" or "available". When someone sends a request to the central system, the system would determine which "available" taxi is the closest to that person's location. A notification would then be sent to the taxi driver, asking him if he wants to go pick up the customer. He would have the option to decline or accept. If he declines, the system would look for another taxi close to the client's location. If he accepts, a notification would be sent to the client, and the real-time location of the taxi would appear on the client's map. The customer would have at any moment, the option of cancelling his request. After the customer gets out of the taxi (that would be determined by GPS), the app would ask him to rate his trip. The entire app system would be manageable from a web service. We must be able to loacte the taxi drivers from the web, as well as be notified of the requests of the customers on the web. We would be able to manually send notifications to both the taxi drivers and the customers. Also, the taxi drivers' apps would have to be activated from that web service. They could also be deactivated. Additional details will be provided if necessary. The image attached is an example of what the customers' app's main page can look like.