UTMC systems depend on a number of agreed, "open" interfaces between systems, system components and applications. These interfaces are defined in a series of "Data Objects" which specify the content and structure of the data being exchanged.

At a UTMC instation (the data management centre) a common database is used to hold all system information and thereby make it available to, for example, a traffic management application. The database and traffic management application may be from different suppliers and so the Data Objects are used to ensure that each supplier understands and can use the data provided by the other.

When data held in the UTMC database is to be sent to a roadside device, for example, a variable message sign, an application at the instation retrieves the data from the database and transmits it to the sign. As there are several suppliers of signs, there is a UTMC data object which defines the interface between the instation and the sign. In this way, signs from multiple suppliers can be connected to the same UTMC system.

All Data Objects are maintained in a Data Objects Registry under the supervision of a Specifications and Standards Group which has representatives from both industry and public sector purchasers.