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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.
3.70 provider service table: The collection of data describing the applications that are registered with a
WAVE device.
3.71 red clearance interval: An optional interval that follows a yellow change interval and precedes the
next conflicting green interval.
3.72 reference lane: A reference lane is a lane drivable by motorized vehicle traffic which also contains a
detailed path definition of the lane’s geometry (a center line path and width) as well as basic attributes
(such as the allowed maneuvers) about the lane. The provided path data may optionally be shared with
another nearby lane (a “computed lane”) in the same intersection. It is one of several basic types of lanes
defined in the message set.
3.73 reference point: A reference point is a complete latitude – longitude – and vertical point on the
reference surface which is used as an initial starting point for subsequent orthogonal offset X, Y, Z values
from that point. All roadway geometry, maps of intersections, lane and curve descriptions, and other
geometrical data that is encoded in this standard uses a systems of local reference points to index and offset
the data that follows.
3.74 registration: One of three modes, or states, of operation known as Registration, Initialization, and
Operations which DSRC systems operate in. The Registration mode is the process by which critical
parameters pertaining to the device and applications using it are entered into the device's Management
Information Base (MIB). Registration must be completed before a DSRC device can be ready for
operations. The registration process is defined in IEEE P1609.3 and is controlled by the WAVE
Management Entity (WME).
3.75 road side unit: A Road Side Unit (RSU) is a DSRC device used to transmit to, and receive from,
DSRC equipped moving vehicles (OBUs). The RSU transmits from a fixed position on the roadside
(which may in fact be a permanent installation or from "temporary" equipment brought on-site for a period
of time associated with an incident, road construction, or other event). RSUs have the ability to transmit
signals with greater power than OBUs and may have TCIP/IP connectivity to other nodes or the Internet.
3.76 semi-actuated operation: A type of traffic control signal operation in which at least one, but not all,
signal phases function on the basis of actuation.
3.77 service channel: Secondary channels used for application-specific information exchanges.
3.78 service table: A data store containing the pertinent information about applications available through
the WAVE device.
3.79 signal head: An assembly of one or more signal lamps. One or more signal heads maybe used to
provide complementary indications to one of more approaches, which may cover multiple lanes. The
definitive mapping to specific lanes can be determined by examining the SPAT and MAP fragment
messages.
3.80 signal phase: The right-of-way, yellow change, and red clearance intervals in a cycle that are assigned
to an independent traffic movement, or combination of movements. Each of these cycles are reflected in
the SPAT message for the lanes that are part of the movement(s), along with its expected timing interval
(which may be updated in signal systems that vary the time interval based on actuation or other methods).
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