Drivers can make driving plans and save traveling time if they can download real-time pictures taken at each driver's point of interest (POI). We designed a system that provides pictures taken by other drivers at a driver's POI. In one naive system design, vehicles send picture data to a central server via a cellular network whenever they take a picture. However, sending all pictures taken by vehicles to the server leads to high processing loads on the server and major amounts of cellular network traffic. In this paper, we propose a scalable data sharing system that uses VANETs and a cellular network for providing a picture taken at POI. For realizing the system, we propose a data upload control method. In this method, all vehicles exchange metadata via VANETs to know the existence of pictures taken by other vehicles and reduce the traffic for uploading pictures taken under a similar condition of other pictures. We evaluate the performance of the proposed method through simulations. The simulation results show that the proposed method reduces the cellular network traffic to 36% in comparison with a system that sends all pictures received by the server to meet all driver POI picture requests.
