Vehicle-to-vehicle and vehicle-to-infrastructure communications are accomplished via a scalable ad hoc geographic routing protocol. As vehicles move along roadways, they can query other vehicles and entities for information. Responses to queries can be used to determine information such as traffic conditions, a retail store sale, that a restaurant has tables available, and/or that parking spaces are available, for example. Businesses, vehicles, and other entities along roadways can geocast pertinent information to vehicles passing by. Vehicles can cache information as it is received.