In response to detecting a traffic event such as a motorcycle lane splitting or an accident, a vehicle broadcasts a notification over a V2V communication channel. Traffic events may be detected using sensor systems of the vehicle or in response to messages reporting the event. Notifications may be received from the vehicle over a cellular communication channel. Roadside infrastructure, such as DSRC or cellular communication installations receive the notification and may rebroadcast it to adjacent vehicles. A DSRC installation may broadcast the message by way of a cellular communication installation and vice versa. The vehicle may provide a cellular notification by way of a driver's mobile device connected to a controller of the vehicle.