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SAE J2735-Draft-Rev26 [issued: 09-18-08]
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This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
3.11 Controller Assembly: A complete electrical device mounted in a cabinet for controlling the operation
of a highway traffic signal.
3.12 Controller Unit: That part of a controller assembly that is devoted to the selection and timing of the
display of signal indications.
3.13 cycle: One complete sequence of signal indications.
3.14 cycle length: The duration of one complete sequence of signal indications. The cycle length is not
generally fixed at actuated controllers.
3.15 dark mode: The lack of all signal indications at a signalized location. (The dark mode is most
commonly associated with power failures, ramp meters, beacons, and some movable bridge signals.) Note
that when the SPAT message is used to convey the status of a non-signalized 4-way stop type of
intersection, if an approach is modeled as being in the dark mode, it would indicate that the signage is
missing (normally a flashing red stop would be indicated).
3.16 data: Representations of static or dynamic entities in a formalized manner suitable for
communication, interpretation, or processing by humans or by machines.
3.17 data concept: Any of a group of data dictionary structures defined in this standard (e.g., data element,
data element concept, entity type, property, value domain, data frame, or message) referring to abstractions
or things in the natural world that can be identified with explicit boundaries and meaning and whose
properties and behavior all follow the same rules.
3.18 data consumer: Any entity in the ITS environment which consumes data from others.
3.19 data dictionary: An information technology for documenting, storing and retrieving the syntactical
form (i.e., representational form) and some usage semantics of data elements and other data concepts. The
major message sets of ITS, of which DSRC is but one, are kept and represented in a data dictionary.
3.20 data element: A syntactically formal representation of some single unit of information of interest
(such as a fact, proposition, observation, etc.) with a singular instance value at any point in time, about
some entity of interest (e.g., a person, place, process, property, object, concept, association, state, event). A
data element is considered indivisible.
3.21 data frame: (formerly: Data Structure, which appears in the early ITS efforts, is now more commonly
called a Data Frame. The definition and meaning, which follows, remains the same.): Any construct used
to represent the contents of a Data Dictionary. From a computer science perspective, data frames are
viewed as logical groupings of other data frames and of data elements to describe "structures" or parts of
messages used in this and other standards. A data frame is a collection of one or more other data concepts
in a known ordering. These data concepts may be simple (data elements) or complex (data frames).
3.22 data plane: The communication protocols defined to carry application and management data across
the communications medium.
3.23 data registry: An advanced data dictionary that contains not only data about data elements in terms of
their names, representational forms and usage in applications, but also substantial data about the semantics
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