Accessible
pedestrian signal (APS). A device that communicates information
about pedestrian timing in nonvisual format such as audible tones,
verbal messages, and/or vibrating surfaces. (MUTCD)
Actuated operation. A type of traffic control signal
operation in which some or all signal phases are operated on the basis
of actuation. (MUTCD)
Actuation. Initiation of a change in or extension
of a traffic signal phase through the operation of any type of detector.
(MUTCD)
Actuation indicator. Either a light, a tone, a voice
message, or both audible and visual indicators that indicate to pedestrians
that the button press has been accepted.
Alert tone at onset of walk interval. A very brief
burst of high frequency sound, rapidly decaying to a 500 Hz WALK tone,
to alert pedestrians to the exact onset of the walk interval.
APS. See Accessible pedestrian signal.
Audible beacon. Use of a sound source to provide
directional orientation and alignment information.
Automatic volume adjustment. An APS volume control
that is automatically responsive to ambient (background) sound; automatic
gain control.
Braille street name. Provision of the name of the associated
street in Braille above the APS pushbutton.
Button actuated timer (BAT). See Extended button
press.
Clearance interval indicator. Tones sounding during
the pedestrian clearance interval that are differentiated from the
walk interval indicator (tones).
Controller unit. That part of a controller assembly
that is devoted to the selection and timing of the display of signal
indications. (MUTCD)
Crosswalk. (a) that part of a roadway at an intersection
included within the connections of the lateral lines of the sidewalks
on opposite sides of the highway measured from the curbs or in the
absence of curbs, from the edges of the traversable roadway, and in
the absence of a sidewalk on one side of the roadway, the part of
a roadway included within the extension of the lateral lines of the
sidewalk at right angles to the centerline; (b) any portion of a roadway
at an intersection or elsewhere distinctly indicated for pedestrian
crossing by lines or other markings on the surface. (MUTCD)
Crosswalk map. See Tactile map.
Cycle Length. The time required for one complete
sequence of signal indications. (MUTCD)
Detectable warning. A standardized surface feature
built in or applied to walking surfaces or other elements to warn
visually impaired people of hazards on a circulation path.
Detector. A sensing device used for determining the
presence or passage of vehicles or pedestrians. (MUTCD)
Extended button press. On APS, holding the ped button
down between 1-3 sec. may activate special features, including audible
beaconing and extended pedestrian clearance interval.
Fixed time operation. See Pretimed operation.
Flashing (flashing mode). A mode of operation in
which a traffic signal indication is turned on and off repetitively.
(MUTCD)
Full-actuated operation. A type of traffic control signal operation
in which all signal phases function on the basis of actuation. (MUTCD)
Intersection. (a) the area embraced within the prolongation
or connection of the lateral curb lines, or if none, the lateral boundary
lines of the roadways of two highways that join one another at, or
approximately at, right angles, or the area within which vehicles
traveling on different highways that join at any other angle may come
into conflict; (b) the junction of an alley or driveway with a roadway
or highway shall not constitute an intersection. (MUTCD)
Interval. The part of a signal cycle during which
signal indications do not change. (MUTCD)
Interval sequence. The order of appearance of signal indications
during successive intervals of a signal cycle. (MUTCD)
Locator signal. See Pushbutton locator tone.
Long button press. See Extended button press.
Long cane. A cane individually prescribed to provide
safety and orientation information to persons who are blind or visually
impaired; typically much longer than a support cane and not intended
for support; typically has a white, reflective surface.
Major street. The street normally carrying the higher
volume of vehicular traffic. (MUTCD)
Minor street. The street normally carrying the lower
volume of vehicular traffic. (MUTCD)
Passive
pedestrian detection. A feature that uses sensors (piezo-electric,
infrared, microwave, or video camera serving remote sensor software)
to trigger, cancel, or lengthen pedestrian timing, or to trigger the
pushbutton locator tone when the pedestrian enters the detection zone.
Pedestrian. People who travel on foot or who use assistive
devices, such as wheelchairs, for mobility.
Pedestrian change interval. An interval during which
the flashing UPRAISED HAND (symbolizing DONT WALK) signal indication
is displayed. When a verbal message is provided at an accessible pedestrian
signal, the verbal message is "wait." (MUTCD)
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Pedestrian
clearance time. The time provided for a pedestrian crossing
in a crosswalk, after leaving the curb or shoulder, to travel to the
center of the farthest traveled lane or to a median. (MUTCD)
Pedestrian phase (or ped phase). The cycle of pedestrian
timing consisting of three parts: (1) The walk interval (WALK sign);
(2) the pedestrian clearance interval (flashing DON’T WALK);
and the pedestrian change interval (steady DON’T WALK).
Pedestrian signal head. A signal head, which contains
the symbols WALKING PERSON (symbolizing WALK) and UPRAISED HAND (symbolizing
DON’T WALK), that is installed to direct pedestrian traffic
at a traffic control signal. (MUTCD).
Pedhead. See Pedestrian signal head.
Permissive mode. A mode of traffic control signal operation
in which, when a CIRCULAR GREEN signal indication is displayed, left
or right turns may be made after yielding to pedestrians and/or oncoming
traffic. (MUTCD)
Preemption control. The transfer of normal operation
of a traffic control signal to a special control mode of operation.
(MUTCD)
Pretimed operation. A type of traffic control signal
operation in which none of the signal phases function on the basis
of actuation. (MUTCD)
Priority control. A means by which the assignment
of right-of-way is obtained or modified. (MUTCD)
PROWAAC. Public Rights of Way Access Advisory Committee
of the U.S. Access Board, that includes advocates, engineers, architects,
and public works officials.
Protected mode. A mode of traffic control signal
operation in which left or right turns may be made when a left or
right GREEN ARROW signal indication is displayed. (MUTCD)
Pushbutton. A button to activate pedestrian timing.
(MUTCD)
Pushbutton locator tone. A repeating sound that informs
approaching pedestrians that they are required to push a button to
actuate pedestrian timing and that enables pedestrians who have visual
disabilities to locate the pushbutton. (MUTCD)
Pushbutton message. A speech message that provides additional
information when the APS pedestrian pushbutton is pushed.
Remote activation. A handheld pushbutton device allowing
a pedestrian to send a message over a short distance to call the ped
phase.
Semiactuated operation. A type of traffic control
signal operation in which at least one, but not all, signal phases
function on the basis of actuation. (MUTCD)
Signal head. An assembly of one or more signal faces together
with the associated signal housings. (MUTCD)
Signal indication. The illumination of a signal lens or equivalent
device. (MUTCD)
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. (MUTCD)
Signal section. The assembly of a signal housing,
signal lens, and light source with necessary components to be used
for providing one signal indication. (MUTCD)
Signal timing. The amount of time allocated for the display
of a signal indication. (MUTCD)
Signal warrant. A threshold condition that, if found to be
satisfied as part of an engineering study, shall result in analysis
of other traffic conditions or factors to determine whether a traffic
control signal or other improvement is justified. (MUTCD)
Steady (steady mode). The continuous illumination
of a signal indication for the duration of an interval, signal phase,
or consecutive signal phases. (MUTCD)
Tactile. An object that can be perceived using the
sense of touch.
Tactile arrow (aligned in direction of travel). A
raised (tactile) arrow in an APS pushbutton that helps users know
which crosswalk is actuated by the pushbutton.
Tactile map. A raised schematic map (located on an
APS pushbutton housing) that shows what will be encountered as the
pedestrian negotiates the crosswalk controlled by that push button.
Traffic control signal (traffic signal). Any highway
traffic signal by which traffic is alternately directed to stop and
permitted to proceed. (MUTCD)
Vibrotactile pedestrian device. A device that communicates,
by touch, information about pedestrian timing using a vibrating surface.
(MUTCD)
Walk interval. An interval during which the WALKING PERSON
(symbolizing WALK) signal indication is displayed. When a verbal message
is provided at an accessible pedestrian signal, the verbal message
is "walk sign." (MUTCD)
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Glossary
