Methods and systems are disclosed for participative sensing of events and conditions by road vehicles, collection of this data from a large number of road vehicles by a central server, processing the data to identify events and conditions which may be of interest to other vehicles in a particular location, and sending notifications of the events and conditions to vehicles. A large number of vehicles use participative sensing systems to identify a safety-related event or condition which should be reported to the central server—such as a large pothole, an obstacle in the roadway, an icy road surface, a traffic accident, etc. The central server stores and aggregates the data, filters it and ages it. Vehicles requesting advisories from the central server will receive notices of safety-related events and conditions based on their location and heading. Driver warnings can be issued, and vehicle systems may respond to the notices.