 |
 |
 |
 |
|
 |
 |
SAE J2735-Draft-Rev28 [issued: 11-10-08]
-
16 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
3.40 intelligent transportation systems (ITS): Systems that apply modern technology to transportation
problems. Another appropriate meaning of the ITS acronym is integrated transportation systems, which
stressed that ITS systems will often integrate components and users from many domains, both public and
private.
3.41 interoperability: The ability to share information between heterogeneous applications and systems.
3.42 intersection: In the context of this standard an intersection is a nexus where two or more approaches
meet and vehicles and other type users may travel between the connecting links. Typically this is a
signalized intersection when considered by this standard, and as such the modes of allowed travel are
reflected in the signal phases, the geometry of the intersection itself, and the local regulatory environment.
The messages of this standard convey some of this information to the traveling public. Specifically, the
MAP message conveys the relevant the road geometry, while the SPAT message conveys the current signal
indication to allow and control movement in the intersection.
3.43 intersection control beacon: A beacon used only at an intersection to control two or more directions
of travel.
3.44 interval: The part of a signal cycle during which signal indications are stable and do not change. In
the SPAT message the current timing value for the remaining interval time estimate as well as the
anticipated interval for yellow change interval is provided for each lane. Because signal interval times
commonly change based on triggering events in many types of signaling systems, the value provided in the
SPAT message may represent a minimal value that is extended and updated as the message is re-issued
each time.
3.45 interval sequence: 3.48 interval sequence: The order of appearance of signal indications during
successive intervals of a signal cycle.
3.46 ITIS: International Traveler Information Systems, the term commonly associated with the standard for
incident phrases developed by the SAE ATIS Committee in conjunction with ITE TMDD and other
standards. This work contains a wide variety of standard phrases to describe incidents and is expected to be
used throughout the ITS industry. The codes found there can be used for sorting and classifying types of
incident events, as well as creating uniform human readable phrases. In the capacity of classifying incident
types, ITIS phrases are used in many areas. ITIS phrases can also be freely mixed with text and used to
describe many incidents.
3.47 lane: In the context of this standard a lane is a portion of the transportation network (typically a
section of roadway geometry) which is being described (its paths and various attributes about it) or referred
to. In the DSRC message set, the lane object is widely used. Lanes consist not only of sections of
“drivable” roadway trasversed by motor vehicles, but other types of lanes including pedestrian and bicycle
walkways, trains and transit lanes, and certain types of dividers and barriers. When used in describing an
intersection, a lane is defined for each possible path into and out of the intersection (in the MAP message),
and the current signal phase (and therefore the allowed movements) then applicable to that lane or its
approach is provided in the SPAT message.
3.48 lane-use control signal: A signal face displaying signal indications to permit or prohibit the use of
specific lanes of a roadway or to indicate the impending prohibition of such use.
3.49 link: A service channel being used in support of application data transfer needs.