A device may receive basic safety message (BSM) data from vehicles, and may determine, based on a quantity of the vehicles and speed data identified in the BSM data, a primary geofence area that includes a first set of the vehicles. The device may determine a secondary geofence area based on the speed data and the quantity of the vehicles, wherein the secondary geofence area is greater in size than the primary geofence area. The device may determine a difference between the primary geofence area and the secondary geofence area to generate a difference geofence area that includes a second set of the vehicles that is different than the first set of the vehicles. The device may generate a multicast message based on the BSM data associated with the second set of the vehicles, and may broadcast the multicast message to the first set of the vehicles.