The set of TestMessage messages are used to provide expandable messages for local and regional deployment use. This is intended to support the development new message and information exchanges of their own within the common framework of the overall V2X message set and this data dictionary. A few common data elements are provided for consistency, while the remainder of the message content can be defined by the developer using the normal regional methods. It is anticipated that over time the concepts developed in these messages will migrate into the data dictionary and message set itself.