WZSC Glossary
Browse the glossary using this index
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1 |
|---|
15th percentile speedthe speed at or below which 15 percent of vehicles travel. Also, see Speed distribution. | |
8 |
|---|
85th-Percentile SpeedThe speed at or below which 85 percent of the motor vehicles travel. Also, see Speed distribution. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
A |
|---|
AADT | |
AASHTO | |
Acceleration Development RateThe rate at which the centripetal acceleration necessary to negotiate a horizontal curve is developed on the transition segment leading up to the curve. | |
Accessible Pedestrian SignalA device that communicates information about pedestrian signal timing in non-visual format such as audible tones, speech messages, and/or vibrating surfaces. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
Accessible Pedestrian Signal DetectorA device designated to assist the pedestrian who has visual or physical disabilities in activating the pedestrian phase. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
Active Grade Crossing Warning SystemThe flashing-light signals, with or without warning gates, together with the necessary control equipment used to inform road users of the approach or presence of rail traffic at grade crossings. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
ACTIVITY AREA | |
Actual Sight DistanceThe sight distance provided by the highway as designed. | |
Actuated OperationA type of traffic control signal operation in which some or all signal phases are operated on the basis of actuation. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
ActuationInitiation of a change in or extension of a traffic signal phase through the operation of any type of detector. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
ADA | |
ADAAG | |
ADT | |
ADVANCE FLAGGERAn additional flagger(s), stationed
in advance of the primary flagger, responsible
for warning approaching traffic that traffic is slowed or
stopped ahead and that they need to slow down themselves. The
advance flagger is preceded by
additional flagger signing – see Advance
Flagger detail. The
advance flagger does not stop
traffic, and uses the
SLOW sign paddle only to
get the approaching drivers’ attention. | |
Advance PreemptionThe notification of approaching rail traffic that is forwarded to the highway traffic signal controller unit or assembly by the railroad or light rail transit equipment in advance of the activation of the railroad or light rail transit warning devices. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
Advance Preemption TimeThe period of time that is the difference between the required maximum highway traffic signal preemption time and the activation of the railroad or light rail transit warning devices. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
ADVANCE WARNING AREAAn essential portion of all work zones and
may vary from a series
of signs starting a mile or more in advance of the work space to a single
sign or flashing lights on a
work vehicle. | |
Advisory Speed | |
AFAD | |
Alley | |
Altered Speed ZoneA speed limit, other than a statutory speed limit, that is based upon an engineering study. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
ANSI | |
ApproachAll lanes of traffic moving toward an intersection or a midblock location from one direction, including any adjacent parking lane(s). MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
ARROW BOARDSLighted sign panels conforming
to the requirements of the MUTCD with a matrix of
lights capable of either flashing or sequential
display of directional mode arrows or chevrons or non-directional
(caution) mode. These devices are also referred to as (sequential)
arrow panels. | |
Arterial Highway (Street) | |
AT GRADE CROSSING (CROSS TRAFFIC ONLY)Railway right-of-way (ROW) over which no other traffic may pass, except to
cross at grade level crossings. A median strip
right-of-way with grade-level crossing at intersection streets is included. | |
AT GRADE CROSSING (MIXED AND CROSS TRAFFIC) | |
Attended Lane (Manual Lane)A toll lane adjacent to
a toll booth occupied by
a human toll collector who makes change, issues receipts, and
perform other toll-related functions. Attended lanes at toll plazas typically
require vehicles to stop to
pay the toll. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Automatic Lane | |
Average Annual Daily Traffic (AADT)The total volume of traffic passing a
point or segment of a highway facility in
both directions for one year divided by the number of days in the
year. Normally, periodic daily traffic volumes are
adjusted for hours of the day counted, days of the week, and
seasons of the year to arrive at average annual daily traffic.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Average Daily Traffic (ADT)The average 24 hour volume, being the total volume during a stated
period divided by the number of days in that period. Normally, this
would be periodic daily traffic volumes over
several days, not adjusted for days of the week or seasons of the
year. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Average Day | |
Average Speed | |
B |
|---|
BackplateSee Signal Backplate.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
BARRICADES | |
Barrier-Separated LaneA preferential lane or
other special purpose lane that is separated from the adjacent
general-purpose lane(s) by a physical barrier. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
BeaconA highway traffic signal
with one or more signal sections that
operates in a flashing mode.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
BEACON (TRUCK-MOUNTED) | |
Bicycle | |
Bicycle FacilitiesA general term denoting improvements and provisions that
accommodate or encourage bicycling, including parking and storage
facilities, and shared roadways not
specifically defined for bicycle use.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Bicycle Lane | |
BikewayA generic term for any road, street, path, or way
that in some manner is specifically designated for bicycle travel,
regardless of whether such facilities are designated for the
exclusive use of bicycles or are to be
shared with other transportation modes. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
BLOCKADE VEHICLE | |
Brake Reaction TimeThe elapsed time between recognition of an object in roadway ahead and application of the brakes. | ||
Braking DistanceThe distance traveled while braking to a complete stop. | ||
BUFFER SPACE | ||
BUFFER SPACESA section of clear road between the taper and the work space providing an extra margin of safety for both traffic and workers. The buffer space should be kept clear of vehicles, equipment, materials and personnel to provide a clear recovery area. | ||
Buffer-Separated LaneA preferential lane or
other special purpose lane that is separated from the adjacent
general-purpose lane(s) by a pattern of standard longitudinal
pavement markings that is wider than a normal or wide lane line
marking. The buffer area might
include rumble strips,
textured pavement, or channelizing devices such as tubular markers or
traversable curbs, but does not include a physical barrier.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
C |
|---|
Cantilevered Signal StructureA structure, also referred to as a mast arm, that is rigidly
attached to a vertical pole and is used to provide overhead support
of highway traffic signal
faces or grade crossing signal
units. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
CATENARYAn overhead wire conductor and support system that supplies the
750-volt direct current (DC) power to the streetcar’s current
collecting pantograph. | |
Center Line Markings | |
CertificationA process which assesses an individual's knowledge and skills to determine if the individual meets a minimum standard of qualification. | |
CFR | |
Changeable Message SignA sign that is capable
of displaying more than one message (one of which might be a
"blank" display), changeable manually, by remote control, or by
automatic control. Electronic-display changeable message signs are
referred to as Dynamic Message Signs in the National Intelligent
Transportation Systems (ITS) Architecture and
are referred to as Variable Message Signs in the National
Electrical Manufacturers Association (NEMA) standards publication.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Channelizing DevicesThe function of channelizing devices is to warn road users of conditions created by work activities in or near the roadway and to guide road users. ... Channelizing devices provide for smooth and gradual vehicular traffic flow from one lane to another, onto a bypass or detour, or into a narrower traveled way. They are also used to channelize vehicular traffic away from the work space, pavement drop-offs, pedestrian or shared-use paths, or opposing directions of vehicular traffic. ... Channelizing devices include cones, tubular markers, vertical panels, drums, barricades, and longitudinal channelizing devices. MUTCD 2009 Edition with May 2012 | |
Channelizing Line Markings | |
CHASE VEHICLEThe vehicle that enters
the road first in a
rolling slowdown. The chase vehicle moves forward
with traffic in front of
the rolling blockade, positioning itself behind the last through
vehicle before
entering the work space. Seeing the
chase vehicle go by,
workers can move into
the open travel lanes and begin working. | |
ChockA wedge or block for blocking the movement of a wheel. | |
Circadian RhythmsPhysical, mental, and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness. | |
Circular IntersectionAn intersection that has
an island, generally
circular in design, located in the center of the intersection where
traffic passes to the
right of the island. Circular
intersections include
roundabouts, rotaries,
and traffic circles.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Circulatory RoadwayThe roadway within a
circular intersection
on which traffic travels in a
counterclockwise direction around an island in the center
of the circular intersection.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Clear Storage DistanceWhen used in Part 8, the distance available for vehicle storage
measured between 6 feet from the rail nearest the intersection to the
intersection stop line or the
normal stopping point on the highway. At skewed
grade crossings and
intersections, the
6-foot distance shall be measured
perpendicular to the nearest rail either along the center line or
edge line of the highway, as
appropriate, to obtain the shorter distance. Where exit gates are used,
the distance available for vehicle storage is
measured from the point where the rear of the vehicle would be clear
of the exit gate arm. In
cases where the exit gate arm is
parallel to the track(s) and is not perpendicular to the highway, the distance
is measured either along the center line or edge line of the
highway, as
appropriate, to obtain the shorter distance. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Clear ZoneThe total roadside border area, starting at the edge of the traveled way, that is available for an errant driver to stop or regain control of a vehicle. This area might consist of a shoulder, a recoverable slope, and/or a non-recoverable, traversable slope with a clear run-out area at its toe. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | ||
CMSchangeable message
sign MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Coefficient of FrictionA dimensionless parameter that quantifies the resistance to sliding at the interface of two surfaces. | |
Collector HighwayA term denoting a highway that in rural
areas connects small towns and local highways to arterial
highways, and in urban
areas provides land access and traffic circulation
within residential, commercial, and business areas and connects
local highways to the
arterial highways.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Competent Person"One who is capable of identifying existing and predictable hazards in the surroundings or working environments which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them." OSHA (29 CFR 1926 Subpart C). | |
Concurrent Flow Preferential LaneA preferential lane that
is operated in the same direction as the adjacent mixed flow lanes,
separated from the adjacent general-purpose freeway lanes by a
standard lane stripe, painted buffer, or barrier.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
CONES | |
Conflict MonitorA device used to detect and respond to improper or conflicting
signal indications and
improper operating voltages in a traffic controller
assembly.MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Constant Warning Time DetectionA means of detecting rail traffic that
provides relatively uniform warning time for the approach of trains or
light rail transit traffic that are not
accelerating or decelerating after being detected.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Contiguous Lane | |
Controller Assemblya complete electrical device mounted in a cabinet for controlling
the operation of a highway traffic
signal. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Controller UnitThat part of a controller assembly
that is devoted to the selection and timing of the display of
signal indications.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Conventional Road | |
Counter-Flow LaneA lane operating in a direction opposite to the normal flow of
traffic designated for
peak direction of travel during at least a portion of the day.
Counter-flow lanes are usually separated from the off-peak
direction lanes by tubular markers or
other flexible channelizing devices, temporary lane separators, or
movable or permanent barrier. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
CrashworthyA characteristic of a roadside appurtenance that has been
successfully crash tested in accordance with a national standard
such as the National Cooperative Highway Research
Program Report 350, "Recommended Procedures for the Safety
Performance Evaluation of Highway Features."
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
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 center line; (b) Any portion of a roadway at an intersection or
elsewhere distinctly indicated as a pedestrian crossing by
pavement marking lines on the surface, which might be supplemented
by contrasting pavement texture, style, or color.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Crosswalk Lines | |
Cycle LengthThe time required for one complete sequence of signal indications.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
D |
|---|
Dark ModeThe lack of all signal indications at
a signalized location. (The dark mode is most commonly associated
with power failures, ramp meters, hybrid beacons,
beacons, and some
movable bridge
signals.) MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
dBAA-weighted decibels | |
Decision Sight DistanceThe distance required for a driver to detect an unexpected or otherwise difficult-to-perceive information source or hazard in a roadway environment that may be visually cluttered, recognize the hazard or its potential threat, select an appropriate speed and path, and initiate and complete the required safety maneuver safely and efficiently. See also Sight Distance, Stopping Sight Distance, Passing Sight Distance, and Intersection Sight Distance. | ||
Delineator | |
Design Speed | |
Design Vehicle | |
Designated Bicycle Route | |
Designated design speed | |
DetectableHaving a continuous edge within 6 inches of the surface so that
pedestrians who have
visual disabilities can sense its presence and receive usable
guidance information. | |
DetectorA device used for determining the presence or passage of vehicles or pedestrians.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
DEVICE SPACINGThe longitudinal distances between channelization devices (cones, tubular markers,
drums) in a taper or along tangent
sections of the work and buffer spaces. | |
DownstreamA term that refers to a location that is encountered by traffic subsequent to
an upstream location as
it flows in an "upstream to
downstream" direction. For example, "the downstream end of a lane
line separating the turn lane from a through lane on the approach to an
intersection" is the
end of the lane line that is closest to the intersection.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Dropped LaneA through lane that becomes a mandatory turn lane on a conventional roadway,
or a through lane that becomes a mandatory exit lane on a freeway or expressway. The end of
an acceleration lane and reductions in the number of through lanes
that do not involve a mandatory turn or exit are not considered
dropped lanes. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Drums (Barrels)Lightweight, flexible, and deformable barrel-shape channelization
devices used to temporarily redirect traffic traveling
through a work zone or incident
response area. Drums can be used in tapers and along
tangent areas to separate traffic from a
work space and guide
traffic along a
desired path. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Dual-Arrow Signal SectionA type of signal section
designed to include both a yellow arrow and a green arrow.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Dynamic Envelope | |
Dynamic Exit Gate Operating ModeA mode of operation where the exit gate operation is
based on the presence of vehicles within the
minimum track clearance
distance. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
E |
|---|
Edge Line MarkingsWhite or yellow pavement marking lines that delineate the right or
left edge(s) of a traveled way.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
EDGE OF TRAVELED WAYThe traveled way is the
portion of the highway for the
movement of vehicles not including
shoulders. The edge of
traveled way is often
delineated by the “fog line” or edge of
pavement. | |
Electronic Toll Collection (ETC)A system for automated collection of tolls from moving or stopped
vehicles through
wireless technologies such as radio-frequency communication or
optical scanning. ETC systems are
classified as one of the following: 1. systems that require users
to have registered toll accounts, with the use of equipment inside
or on the exterior of vehicles, such as a
transponder or barcode decal, that communicates with or is detected
by roadside or overhead receiving equipment, or with the use of
license plate optical scanning, to automatically deduct the toll
from the registered user account, or 2. systems that do not require
users to have registered toll accounts because vehicle license plates
are optically scanned and invoices for the toll amount are sent
through postal mail to the address of the vehicle owner.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Electronic Toll Collection (ETC) Account Only Lane | |
Emergency-Vehicle Hybrid Beacon | |
Emergency-Vehicle Traffic Control Signal | |
End-of-Roadway MarkerA device used to warn and alert road users of the end
of a roadway in other than
temporary traffic control
zones. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Engineering JudgmentThe evaluation of available pertinent information, and the
application of appropriate principles, provisions, and practices as
contained in this Manual and other sources, for the purpose of
deciding upon the applicability, design, operation, or installation
of a traffic control
device. Engineering judgment shall be exercised by
an engineer, or by an individual working under the supervision of
an engineer, through the application of procedures and criteria
established by the engineer. Documentation of engineering judgment
is not required. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Engineering StudyThe comprehensive analysis and evaluation of available pertinent
information, and the application of appropriate principles,
provisions, and practices as contained in this Manual and other
sources, for the purpose of deciding upon the applicability,
design, operation, or installation of a traffic control
device. An engineering study shall be performed by
an engineer, or by an individual working under the supervision of
an engineer, through the application of procedures and criteria
established by the engineer. An engineering study shall be documented.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Entrance GateAn automatic gate that can be
lowered across the lanes approaching a grade crossing to
block road users from
entering the grade crossing.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
EPA | |
ETC | |
EV | |
Exact Change Lane (Automatic Lane) | |
Exit GateAn automatic gate that can be
lowered across the lanes departing a grade crossing to
block road users from
entering the grade crossing by
driving in the opposing traffic
lanes. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Exit Gate Clearance TimeFor Four-Quadrant Gate systems at
grade crossings, the
amount of time provided to delay the descent of the exit gate arm(s) after
entrance gate arm(s)
begin to descend. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Exit Gate Operating ModeFor Four-Quadrant Gate systems at
grade crossings, the
mode of control used to govern the operation of the exit gate arms.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Expressway | ||
EXTENDED TRAFFIC QUEUE | |
F |
|---|
FHWA | |
FlaggerA person who actively controls the flow of vehicular traffic into and/or through a temporary traffic control zone using hand-signaling devices or an Automated Flagger Assistance Device (AFAD). MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | ||
FLAGGER TAPER | |
FlasherA device used to turn highway traffic signal
indications on and off at a repetitive rate of approximately once
per second. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Flashingan operation in which a light source, such as a traffic signal indication, is
turned on and off repetitively. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Flashing ModeA mode of operation in which at least one traffic signal indication in
each vehicular signal face of a
highway traffic signal
is turned on and off repetitively. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Flashing-Light SignalsA warning device consisting of two red signal indications
arranged horizontally that are activated to flash alternately when
rail traffic is
approaching or present at a grade crossing.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
FOG LINEA pavement marking line that delineates the edge of the traveled way. Also
referred to as the “edge line.” | |
Foot-candleOne lumen per square foot. | |
FRA | |
Freeway | ||
FTA | |
Full-Actuated OperationA type of traffic control signal
operation in which all signal phases function
on the basis of actuation.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
G |
|---|
Gatean automatically-operated or manually-operated traffic control device
that is used to physically obstruct road users such that
they are discouraged from proceeding past a particular point on a
roadway or pathway, or such that
they are discouraged from entering a particular grade crossing, ramp,
lane, roadway, or facility.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Grade Crossing | |
Guide Sign | |
H |
|---|
High conspicuity tape | |
HIGH SPEEDA designated (posted) speed of 45 mph or
above. | |
HIGH VOLUMEWhile defined by each Agency, typically identified as average daily traffic
(ADT) volumes greater than 2000 vehicles per day. | |
High-Occupancy Vehicle (HOV) | |
High-visibility vest/apparel | |
Highway | ||
Highway Traffic SignalA power-operated traffic control device
by which traffic is warned or
directed to take some specific action. These devices do not include
power-operated signs, steadily-illuminated pavement markers,
warning lights (see
Section 6F.83), or steady burning electric lamps. | |
Highway-Light Rail Transit Grade Crossing | |
Highway-Rail Grade Crossing | |
HOT | |
HOTM | |
HOTO | |
HOV | |
HOV Lane | |
Hybrid Beacon | |
I |
|---|
ILEV | |
In-Roadway LightsA special type of highway traffic signal
installed in the roadway surface to
warn road users that they
are approaching a condition on or adjacent to the roadway that might not
be readily apparent and might require the road users to slow
down and/or come to a stop. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Inferred design speed | |
Inherently Low Emission Vehicle (ILEV) | |
Interchange | |
InterconnectionWhen used in Part 8, the electrical connection between the railroad
or light rail transit active warning system and the highway traffic signal
controller assembly
for the purpose of preemption.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Intermediate InterchangeAn interchange with an
urban or rural route that is not a major or minor interchange as
defined in this Section. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Internal Traffic Control PlanA traffic control plan developed to control the flow of construction workers, vehicles, and equipment within the work space. | ||
Internal traffic control plan coordinatorA person designated by the contractor as a competent person who
has the ability to recognize hazards associated with the movement
of construction vehicles, equipment,
and personnel within the work space and has the
authority to modify conditions to eliminate those hazards. | |
IntersectionIntersection is defined as follows: (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 might come into conflict. (b) The junction of an
alley or driveway with
a roadway or highway shall not constitute
an intersection, unless the roadway or highway at said
junction is controlled by a traffic control
device. (c) If a highway includes two
roadways that are 30
feet or more apart (see definition of Median), then every
crossing of each roadway of such
divided highway by an
intersecting highway shall be a separate
intersection .(d) If both intersecting highways include two
roadways that are 30
feet or more apart, then every crossing of any two roadways of such
highways shall be a separate
intersection. At a location controlled by a traffic control
signal, regardless of the distance between the separate
intersections as defined in (c) and (d) above: (1) If a stop line, yield line,
or crosswalk has not been
designated on the roadway (within the
median) between the
separate intersections, the two intersections and the roadway (median) between them
shall be considered as
one intersection; (2) Where a stop line, yield line,
or crosswalk is
designated on the roadway on the
intersection approach, the area
within the crosswalk and/or
beyond the designated stop line or yield
line shall be part of the
intersection; and (3) Where a crosswalk is
designated on a roadway on the
departure from the intersection, the intersection shall include the area
extending to the far side of such crosswalk.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Intersection Control BeaconA beacon used only at an
intersection to
control two or more directions of travel. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Intersection Sight DistanceThe corner sight distance available for a vehicle approaching an intersection to see oncoming vehicles approaching from crossing legs (the left and right). | ||
IntervalThe part of a signal cycle during which signal indications do
not change. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Interval SequenceThe order of appearance of signal indications
during successive intervals of a signal
cycle. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
ISEA | |
IslandA defined area between traffic lanes for
control of vehicular movements, for toll collection, or for
pedestrian refuge. It
includes all end protection and approach treatments.
Within an intersection area, a
median or an outer
separation is considered to be an island. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
ITCPA traffic control plan developed to control the flow of construction workers, vehicles, and equipment within the work space. | ||
ITE | |
ITS | |
L |
|---|
Lane DropSee Dropped Lane.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Lane Line Markings | |
Lane-Use Control SignalA signal face displaying
indications to permit or prohibit the use of specific lanes of a
roadway or to indicate
the impending prohibition of such use. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Lateral buffer spaceA "lateral buffer space may be used to
separate the traffic space from the
work space . . . [or a
hazardous area], such as excavations or pavement drop-offs. A
lateral buffer space also
may be used between
two travel lanes, especially [those carrying traffic in opposite
directions]. The width of the lateral buffer space should be determined
by engineering judgment"
[FHWA 2000 (MUTCD: Section
6C.06)]. | |
LED | |
LegendSee Sign Legend.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
LensSee Signal Lens.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Light balloonA self-inflating elliptical lighting fixture designed to produce uniform non-glare illumination. | |
Light Rail Transit Traffic (Light Rail Transit Equipment)Every device in, upon, or by which any person or property can be
transported on light rail transit tracks, including single-unit
light rail transit cars (such at streetcars and
trolleys) and assemblies of multiple light rail transit cars
coupled together. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Locomotive HornAn air horn, steam whistle, or similar audible warning device (see
49 CFR Part 229.129)
mounted on a locomotive or control cab car. The terms "locomotive
horn," "train whistle,"
"locomotive whistle," and "train horn" are used
interchangeably in the
railroad industry. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Logo | |
Longitudinal Markings | |
LouverSee Signal Louver.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
LOW SPEEDA designated (posted) speed of 40 mph or
below. | |
LOW VOLUME | |
LP | |
M |
|---|
Major InterchangeAn interchange with
another freeway or expressway, or an
interchange with a
high-volume multi-lane highway, principal
urban arterial, or major rural route where the interchanging
traffic is heavy or
includes many road users unfamiliar
with the area. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Major Street | |
Malfunction Management UnitSame as Conflict Monitor.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Managed LaneA highway lane or set of
lanes, or a highway facility, for
which variable operational strategies such as direction of travel,
tolling, pricing, and/or vehicle type or
occupancy requirements
are implemented and managed in real-time in response to changing
conditions. Managed lanes are typically buffer- or barrier-separated
lanes parallel to the general-purpose lanes of a highway in which
access is restricted to designated locations. There are also some
highways on which all
lanes are managed. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Manual Lane | |
Maximum Highway Traffic Signal Preemption TimeThe maximum amount of time needed following initiation of the
preemption sequence
for the highway traffic
signals to complete the timing of the right-of-way transfer
time, queue clearance time,
and separation time.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
MAYIndicates an allowed (optional) alternative to a mandatory condition or action. | |
MedianThe area between two roadways of a divided
highway measured from
edge of traveled way
to edge of traveled way.
The median excludes turn lanes. The median width might be different
between intersections,
interchanges, and at
opposite approaches of the same intersection.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
melatoninmelatonin is a hormone produced by the pineal gland that regulates sleep and wakefulness. | |
MillingProcess in which a rotating drum, equipped with special working tools, cuts the pavement to a predetermined depth and reduces the cuttings to a minimum size in the process. Also called cold planing [Webster 1995: p. 125]. | |
Minimum Track Clearance DistanceFor standard two-quadrant warning devices, the minimum track
clearance distance is the length along a highway at one or more
railroad or light rail transit tracks, measured from the highway stop line, warning
device, or 12 feet perpendicular to the track center line, to 6
feet beyond the track(s) measured perpendicular to the far rail,
along the center line or edge line of the highway, as
appropriate, to obtain the longer distance. For Four-Quadrant
Gate systems, the
minimum track clearance distance is the length along a highway at one or more
railroad or light rail transit tracks, measured either from the
highway stop line or entrance
warning device, to the point where the rear of the vehicle would be clear
of the exit gate arm. In
cases where the exit gate arm is
parallel to the track(s) and is not perpendicular to the highway, the distance
is measured either along the center line or edge line of the
highway, as
appropriate, to obtain the longer distance. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Minimum Warning TimeWhen used in Part 8, the least amount of time active warning
devices shall operate prior to
the arrival of rail traffic at a
grade crossing.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Minor InterchangeAn interchange where
traffic is local and
very light, such as interchanges with land
service access roads. Where the sum of the exit volumes is
estimated to be lower than 100 vehicles per day in
the design year, the interchange is
classified as local. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Minor Street | |
MOBILE OPERATIONWork activities where work equipment is continuously moving along
the road at an average speed of 3 mph
or more. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Movable Bridge Resistance GateA type of traffic gate, which is located
downstream of the
movable bridge warning
gate, that provides a physical deterrent to vehicle and/or
pedestrian traffic when placed in
the appropriate position. | |
Movable Bridge SignalA highway traffic signal
installed at a movable bridge to notify traffic to stop during
periods when the roadway is closed to
allow the bridge to open. | |
Movable Bridge Warning GateA type of traffic gate designed to warn,
but not primarily to block, vehicle and/or
pedestrian traffic when placed in
the appropriate position. | |
MPH or mph | |
Multi-LaneMore than one lane moving in the same direction. A multi-lane
street, highway, or roadway has a basic
cross-section comprised of two or more through lanes in one or both
directions. A multi-lane approach has two or
more lanes moving toward the intersection,
including turning lanes. | |
MULTI-LANE ROADA road with at least two
lanes in at least one direction. | |
MUTCD | |
N |
|---|
NCHRP | |
Neutral AreaThe paved area between the
channelizing lines separating an entrance or exit ramp or a
channelized turn lane or channelized entering lane from the
adjacent through lane(s). | |
O |
|---|
Object MarkerA device used to mark obstructions within or adjacent to the
roadway. | |
Occupancy Requirement | |
Occupant | |
Open-Road ETC LaneA non-attended lane that is designed to allow toll payments to be
electronically collected from vehicles traveling at
normal highway speeds.
Open-Road ETC lanes are
typically physically separated from the toll plaza, often
following the alignment of the mainline lanes, with toll plaza lanes for
cash toll payments being on a different alignment after diverging
from the mainline lanes or a subset thereof. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Open-Road TollingA system designed to allow electronic toll collection
(ETC) from vehicles traveling at
normal highway speeds.
Open-Road Tolling might be
used on toll roads or toll facilities in conjunction with toll plazas.
Open-Road Tolling is also
typically used on managed lanes and on
toll facilities that only accept payment by ETC.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Open-Road Tolling PointThe location along an Open-Road ETC lane at
which roadside or overhead detection and receiving equipment are
placed and vehicles are
electronically assessed a toll. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Operating SpeedThe speeds at which vehicles are observed operating during free flow conditions. Free flow speeds are those observed from vehicles whose operations are unimpeded by traffic control devices (e.g., traffic signals) or by other vehicles in the traffic stream. The 85th percentile of the distribution of observed speeds is the most frequently used measure of the operating speed. MUTCD 2009 Edition with May 2012 Revisions 1 and 2 | |
Opposing TrafficVehicles that are
traveling in the opposite direction. At an intersection, vehicles entering from
an approach that is
approximately straight ahead would be considered to be opposing
traffic, but vehicles entering from
approaches on the left or right would not be considered to be
opposing traffic.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
ORTopen-road tolling
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Overhead SignA sign that is placed
such that a portion or the entirety of the sign or its support is
directly above the roadway or shoulder such that
vehicles travel below
it. Typical installations include signs placed on cantilever arms that
extend over the roadway or shoulder, on sign support
structures that span the entire width of the pavement, on mast arms
or span wires that also support traffic control
signals, and on highway bridges that
cross over the roadway.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
overrepresented
Represented in a sample in a proportion higher than the
average or otherwise disproportionately
high. Usually
involves a test of statistical significance for
confidence intervals
surrounding a value among the groups, such as a mean or average.
Often refers to a statistically significant difference between
two or more groups which are mostly alike except in one way in
which one group or another differs in a manner that can not alone
be due to chance. | |
P |
|---|
Pace | |
Parking Area | |
Passing Sight Distance
The distance that drivers must
be able to see along the road ahead to safely
and efficiently initiate and complete passing maneuvers of slower
vehicles on two-lane
highways using the
lane normally reserved for opposing traffic.
See also Sight Distance,
Stopping Sight
Distance, Decision Sight
Distance, and Intersection Sight
Distance. NCHRP REPORT 605
2008. | ||
Passive Grade CrossingA grade crossing where
none of the automatic traffic control
devices associated with an Active Grade Crossing
Warning System are present and at which the traffic control
devices consist entirely of signs and/or markings.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
PathwayA general term denoting a public way for purposes of travel by
authorized users outside the traveled way and
physically separated from the roadway by an open
space or barrier and either within the highway right-of-way
or within an independent alignment. Pathways include shared-use paths, but
do not include sidewalks.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Pathway Grade Crossing | |
Paved | |
PCMSportable changeable message
sign MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Pedestrian | |
Pedestrian Change Interval | |
Pedestrian Clearance TimeThe time provided for a pedestrian crossing in
a crosswalk, after
leaving the curb or shoulder, to travel to
the far side of the traveled way or to a
median.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Pedestrian Facilities | |
Pedestrian Hybrid BeaconA special type of hybrid beacon used to
warn and control traffic at an
unsignalized location to assist pedestrians in
crossing a street or highway at a marked
crosswalk.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Pedestrian Signal HeadA signal head, which
contains the symbols WALKING PERSON
(symbolizing WALK) and
UPRAISED HAND (symbolizing DONT
WALK), that is installed to direct pedestrian traffic at a traffic control
signal. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Permissive ModeA mode of traffic control signal
operation in which left or right turns are permitted to be made
after yielding to pedestrians, if any,
and/or opposing traffic, if
any. When a CIRCULAR GREEN signal indication is
displayed, both left and right turns are permitted unless otherwise
prohibited by another traffic control
device. When a flashing YELLOW ARROW
or flashing RED ARROW
signal indication is
displayed, the turn indicated by the arrow is permitted.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Physical Gore | |
PictographA pictorial representation used to identify a governmental
jurisdiction, an area of jurisdiction, a governmental agency, a
military base or branch of service, a governmental-approved
university or college, a toll payment system, or a
government-approved institution. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
PILOT CARA four-wheeled vehicle no smaller
than a compact pickup, identified by a 36” x 18” PILOT CAR FOLLOW
ME (sign mounted on the
rear) and equipped with a beacon and two-way
radios or other communication devices. The communication devices
shall have a range
suitable for the length and terrain of the project. A vehicle-mounted
PCMS may be used in lieu of
the 36” x 18” rigid sign. | |
PlaqueA traffic control device
intended to communicate specific information to road users through a
word, symbol, or arrow
legend that is placed
immediately adjacent to a sign to supplement the
message on the sign. The difference
between a plaque and a sign is that a plaque
cannot be used alone. The designation for a plaque includes a "P"
suffix. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
PlatoonA group of vehicles or pedestrians traveling
together as a group, either voluntarily or involuntarily, because
of traffic signal
controls, geometrics, or other factors. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
PORTABLE CHANGEABLE MESSAGE SIGN (PCMS) | |
PORTABLE TEMPORARY SIGNALA portable temporary signal is a self contained, self-powered
green-yellow-red traffic signal used
for controlling traffic through a
short term traffic control
section. Portable signals used on state highways shall be on the ODOT
Qualified Products List or Conditional Use List and have State
Traffic Engineer
approval. | |
Portable Traffic Control SignalA temporary traffic control
signal that is designed so that it can be easily transported
and reused at different locations. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Post-Mounted Sign | |
Posted Speed LimitOne of two speed limit types
(statutory speed is
other type); the maximum lawful vehicle speed for a particular
location as displayed on a regulatory sign.
Posted speeds are displayed on regulatory signs in
speed values that are
multiples of 5 mph. | |
Pre-construction meetingA meeting between the owner's representatives and representatives for the contractor(s) to discuss their respective safety requirements and implementation of health and safety provisions pertinent to the work under contract [Hinze 1997: p. 102]. | |
Pre-Maneuver TimeThe time required for a driver to process information relative to a hazard, plot an avoidance course, and initiate the required avoidance maneuver. | |
Pre-qualificationA process by which only selected contractors that meet predetermined performance criteria are entitled to bid on a construction project. The contractor's safety performance is often one of the qualifying criteria [MacCollum 1995: p. 53-54]. | |
Pre-signalTraffic control
signal faces that
control traffic approaching a
grade crossing in
conjunction with the traffic control
signal faces that
control traffic approaching a
highway-highway intersection beyond
the tracks. Supplemental near-side traffic control
signal faces for the
highway-highway intersection are not
considered pre-signals. Pre-signals are typically used where the
clear storage distance
is insufficient to store one or more design vehicles.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Preemption | |
Preferential Lane | |
Pretimed OperationA type of traffic control signal
operation in which none of the signal phases function
on the basis of actuation.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Primary Signal FaceOne of the required or recommended minimum number of signal faces for a
given approach or separate
turning movement, but not including near-side signal faces required
as a result of the far-side signal faces exceeding
the maximum distance from the stop line.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Principal LegendPlace names, street names, and
route numbers placed on guide signs.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Priority Control | |
Private Road Open to Public TravelPrivate toll roads and roads (including any adjacent sidewalks that
generally run parallel to the road) within shopping
centers, airports, sports arenas, and other similar business and/or
recreation facilities that are privately owned, but where the
public is allowed to travel without access restrictions. Roads
within private gated properties (except for gated toll roads) where
access is restricted at all times, parking areas, driving
aisles within parking areas, and
private grade crossings
shall not be included
in this definition. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Project supervisorManages the activities at the construction site, schedules work crews and materials, and is responsible for keeping project on schedule and on budget. | |
Protected ModeA mode of traffic control signal
operation in which left or right turns are permitted to be made
when a left or right GREEN ARROW signal indication is
displayed. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
PROTECTION VEHICLEA vehicle strategically
placed to protect the workers and work
activity. The protection vehicle may be in a stationary
work zone or be the
vehicle immediately
behind the work vehicle(s) in an
array of mobile work vehicles. The
protection vehicle is placed
after the buffer space and
sufficiently in advance of the work space protected
to allow for run-out if hit but not
so far in advance that traffic can enter the
space before the work space.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
PRTperception-response time | |
Public Road | |
PushbuttonA button to activate a device or signal timing for
pedestrians,
bicyclists, or other road users.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Pushbutton Information MessageA recorded message that can be actuated by pressing a pushbutton when the
walk interval is not
timing and that provides the name of the street that the
crosswalk associated
with that particular pushbutton crosses and
can also provide other information about the intersection
signalization or geometry. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Pushbutton Locator ToneA repeating sound that informs approaching pedestrians that a
pushbutton exists to
actuate pedestrian timing or
receive additional information and that enables pedestrians who have
visual disabilities to locate the pushbutton.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Q |
|---|
Queue Clearance TimeWhen used in Part 8, the time required for the design vehicle of
maximum length stopped just inside the minimum track clearance
distance to start up and move through and clear the entire
minimum track clearance
distance. If pre-signals are
present, this time shall be long enough
to allow the vehicle to move
through the intersection, or to
clear the tracks if there is sufficient clear storage
distance. If a Four-Quadrant Gate system is
present, this time shall be long enough
to permit the exit gate arm to lower
after the design vehicle is
clear of the minimum track clearance
distance. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Quiet ZoneA segment of a rail line, with one or a number of consecutive
public highway-rail grade
crossings at which locomotive horns are
not routinely sounded per 49 CFR Part 222.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
R |
|---|
Rail TrafficEvery device in, upon, or by which any person or property can be
transported on rails or tracks and to which all other traffic must yield the
right-of-way by law at grade crossings,
including trains, one or more locomotives coupled (with or without
cars), other railroad equipment, and light rail transit operating
in exclusive or semi-exclusive alignments. Light rail transit
operating in a mixed-use alignment, to which other traffic is not
required to yield the right-of-way by law, is a vehicle and is not
considered to be rail traffic. | |
RAILWAY RIGHT OF WAYThe horizontal and vertical space occupied by the rail system;
includes track, ballast, rail systems, platforms and overhead
catenary system.
Horizontal area is typically measured from curb to curb or fence
line to fence line. This area may be shared by a
variety of vehicles or may be an exclusive
rail corridor. | |
Raised Pavement MarkerA device mounted on or in a road surface that has
a height generally not exceeding approximately 1 inch above the
road surface for a
permanent marker, or not exceeding approximately 2 inches above the
road surface for a
temporary flexible marker, and that is intended to be used as a
positioning guide and/or to supplement or substitute for pavement
markings. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Ramp Control Signal | |
Ramp MeterSee Ramp Control Signal.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Red Clearance IntervalAn interval that follows
a yellow change interval
and precedes the next conflicting green interval.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Regulatory Sign | |
Retroreflective materialRetroreflective material reflects light back towards the source.
For example, retroreflective material reflects vehicle headlights so
that signs, safety clothing, and other safety devices appear more
visible to drivers at night. | |
RetroreflectivityA property of a surface that allows a large portion of the light coming from a point source to be returned directly back to a point near its origin. | |
Right-of-Way [Assignment]The permitting of vehicles and/or
pedestrians to proceed
in a lawful manner in preference to other vehicles or pedestrians by the
display of a sign or signal indications.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Right-of-Way Transfer TimeWhen used in Part 8, the maximum amount of time needed for the
worst case condition, prior to display of the track clearance green
interval. This
includes any railroad or light rail transit or highway traffic signal
control equipment time to react to a preemption call, and
any traffic control signal
green, pedestrian walk and
clearance, yellow change, and red clearance
intervals for conflicting traffic.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Road | |
Road UserA vehicle operator,
bicyclist, or pedestrian, including
persons with disabilities, within the highway or on a
private road open to
public travel. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
RoadwayThat portion of a highway improved,
designed, or ordinarily used for vehicular travel and parking
lanes, but exclusive of the sidewalk, berm, or
shoulder even though
such sidewalk, berm, or
shoulder is used by
persons riding bicycles or other
human-powered vehicles. In the event
a highway includes two
or more separate roadways, the term roadway as used in this Manual
shall refer to any
such roadway separately, but not to all such roadways collectively.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Roadway Network | |
RoundaboutA circular intersection
with yield control at entry, which permits a vehicle on the
circulatory roadway to
proceed, and with deflection of the approaching vehicle
counter-clockwise around a central island.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
RPMRaised pavement marker
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
RRPM | |
Rumble StripA series of intermittent, narrow, transverse areas of
rough-textured, slightly raised, or depressed road surface that
extend across the travel lane to alert road users to unusual
traffic conditions or
are located along the shoulder, along the
roadway center line,
or within islands formed by
pavement markings to alert road users that they
are leaving the travel lanes. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
RUN-OUTThe distance in front of a protection vehicle it
is likely to move if hit. The length of the space between a
protection vehicle and
the work activity should be at least
equal to the run-out. For TMA-equipped protection vehicles,
follow the manufacturer’s recommendations in determining the proper
run-out distance. | |
Rural HighwayA type of roadway normally
characterized by lower volumes, higher speeds, fewer turning
conflicts, and less conflict with pedestrians.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
RV | |
S |
|---|
Safe-PositionedThe positioning of emergency vehicles at an
incident in a manner that attempts to protect both the responders
performing their duties and road users traveling
through the incident scene, while minimizing, to the extent
practical, disruption of the adjacent traffic flow.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
School | |
School Zone | |
Semi-Actuated OperationA type of traffic control signal
operation in which at least one, but not all, signal phases function
on the basis of actuation.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Senior project supervisorThe senior project supervisor has final authority and
responsibility for safety and health on the project, ensuring
correction or abatement of hazards, monitoring for potentially
hazardous conditions, determining that competent persons are
designated by contractors, notifying responsible contractor of
conditions that may cause injury or
illness, and maintaining project safety and health records
[ANSI A10.33-1992
(R1998)]. | |
Separate Turn Signal FaceA signal face that
exclusively controls a turn movement and that displays signal indications
that are applicable only to the turn movement. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Separation TimeThe component of maximum highway
traffic signal preemption time during which the minimum track clearance
distance is clear of vehicular traffic prior to the
arrival of rail traffic.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Shadow Vehicle | |
SHALLIndicates a mandatory condition or action. | |
Shared Roadway | |
Shared Turn Signal FaceA signal face, for
controlling both a turn movement and the adjacent through movement,
that always displays the same color of circular signal indication that
the adjacent through signal face or faces
display. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Shared-Use PathA bikeway outside the
traveled way and
physically separated from motorized vehicular traffic by an open
space or barrier and either within the highway right-of-way
or within an independent alignment. Shared-use paths are also used
by pedestrians (including
skaters, users of manual and motorized wheelchairs, and joggers)
and other authorized motorized and non-motorized users.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
SHORT DURATION WORKShort duration work that involves short stops of up to one hour such as litter cleanup or pothole patching. | |
SHOULDA strong recommendation for an action or practice, and is the standard treatment under normal conditions. | |
SHOULDERThat portion of a road adjoining but
outside of the normal travel lanes. | |
Sidewalk | |
SIGHT DISTANCEThe length along a roadway over which a
driver has uninterrupted visibility – this is known as available
sight distance. Different minimum sight distance design criteria
exist for various operations and maneuvers, including stopping sight
distance, passing sight distance
and intersection sight
distance. Sight distance may be obstructed by
the road surface (hills or
dips) or some feature beyond the shoulder (trees or
vegetation). Also, the length of roadway ahead over
which an object of a specific height is continuously visible to the
driver. | |
SignAny traffic control device
that is intended to communicate specific information to road users through a
word, symbol, and/or arrow
legend. Signs do not
include highway traffic
signals, pavement markings, delineators, or
channelization devices. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Sign Assembly | |
Sign Illumination | |
Sign Legend | |
Sign Panel | |
Signal BackplateA thin strip of material that extends outward from and parallel to
a signal face on all
sides of a signal housing to
provide a background for improved visibility of the signal indications.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal Coordination | |
Signal FaceAn assembly of one or more signal sections that
is provided for controlling one or more traffic movements on a
single approach.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal HeadAn assembly of one or more signal faces that is
provided for controlling traffic movements on
one or more approaches. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal HousingThat part of a signal section that
protects the light source and other required components.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal IndicationThe illumination of a signal lens or
equivalent device. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal LensThat part of the signal section that
redirects the light coming directly from the light source and its
reflector, if any. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal LouverA device that can be mounted inside a signal visor to
restrict visibility of a signal indication from
the side or to limit the visibility of the signal indication to a
certain lane or lanes, or to a certain distance from the stop line.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal PhaseThe 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 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal SectionThe assembly of a signal housing,
signal lens, if any,
and light source with necessary components to be used for
displaying one signal indication.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal SystemTwo or more traffic control
signals operating in signal coordination.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal TimingThe amount of time allocated for the display of a signal indication.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signal VisorThat part of a signal section that
directs the signal indication
specifically to approaching traffic and reduces
the effect of direct external light entering the signal lens.
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Signing | |
Simultaneous PreemptionNotification of approaching rail traffic is
forwarded to the highway traffic signal
controller unit or
assembly and railroad or light rail transit active warning devices
at the same time. MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
Site-specific hazard"Review of plans and specifications to identify the location and nature of assessment potential hazards..." [MacCollum 1995: p. 60]. | |
Skilled construction tradesA grouping of occupations that includes the traditional building trades, such as carpenters, painters, electricians, and cement finishers. | |
Special Purpose Road | |
SpeedSpeed is defined based on the following five classifications:
Average Speed,
Design Speed, 85th-Percentile Speed,
Operating Speed, and
Pace
MUTCD 2009 Edition with
May 2012 Revisions 1
and 2 | |
SPEED (POSTED SPEED)The designated (posted) speed as shown on
roadside signs or, if no signs, the statutory speed set in
Oregon Revised Statutes. | |
Speed deviationSometimes used to indicate Standard deviation of speed (see definition). Also, see Speed distribution. | |
Speed distributionAn arrangement of speed values showing their observed or theoretical frequency of occurrence. | |
Speed Limitthe maximum (or minimum) speed applicable to a section of highway as established by law or regulation. There are two types of speed limits, posted speed and statutory speed, definitions of each are provided. | |
Speed Limit Sign Beacon | |
Speed Measurement Markings | |
Speed Zonea section of highway with a
speed limit that is
established by law or regulation, but which might be different from
a legislatively specified statutory speed limit. | |
Splitter Island | |
SPOTTER | |
Station Crossinga pathway grade crossing
that is associated with a station platform. | |
Statutory speedOne of two speed limit types (posted speed is other type). Numerical speed limits (e.g., 25 mph, 55 mph), established by state law that apply to various classes or categories of roads (e.g. rural expressways, residential streets, primary arterials, etc.) in the absence of posted speed limits. | |
Statutory Speed Limita speed limit
established by legislative action that typically is applicable for
a particular class of highways with
specified design, functional, jurisdictional and/or location
characteristics and that is not necessarily displayed on Speed Limit signs. | |
Steady (Steady Mode)the continuous display of a signal indication for
the duration of an interval, signal phase, or
consecutive signal phases. | |
Stop Beacon | |
Stop Linea solid white pavement marking line extending across approach lanes to
indicate the point at which a stop is intended or required to be
made. | |
Stopping Sight DistanceThe viewable distance required for a driver to see so that he or she can make a complete stop in the event of an unforeseen hazard. See also Sight Distance, Decision Sight Distance, Passing Sight Distance, and Intersection Sight Distance. | ||
Stopping Sight Distance, (Minimum) | ||
Streetsee Highway. | |
Supplemental Signal Facea signal face that is
not a primary signal face
but which is provided for a given approach or separate
turning movement to enhance visibility or conspicuity. | |
Symbol | |
T |
|---|
TAPER | ||
TDDtelecommunication devices for the deaf | |
Temporary Pavement Markings | |
Temporary Traffic Control DeviceAll signs, signals, markings, and other devices use to regulate, warn, or guide traffic in temporary traffic control zones. | ||
Temporary Traffic Control Plan"A temporary traffic control plan (TCP) describes temporary traffic control measures to be used for facilitating road users through a work zone. . . . [The plan] may range in scope from being very detailed, to simply referencing typical drawings contained in [the MUTCD], standard approved highway drawings and manuals, or specific drawings contained in contract documents" [FHWA 2000 (MUTCD: Section 6C.01)]. | ||
Temporary Traffic Control Signala traffic control signal
that is installed for a limited time period. | |
Temporary Traffic Control Zonean area of a highway where road user conditions
are changed because of a work zone or incident
by the use of temporary traffic control
devices, flaggers, uniformed
law enforcement officers, or other authorized personnel. | |
TERMINATION AREAA short distance after the work space that allows
traffic to clear the
work space and return
to normal operation. | |
Theoretical Gorea longitudinal point at the upstream end of a
neutral area at an
exit ramp or channelized turn lane where the channelizing lines
that separate the ramp or channelized turn lane from the adjacent
through lane(s) begin to diverge, or a longitudinal point at the
downstream end of a
neutral area at an
entrance ramp or channelized entering lane where the channelizing
lines that separate the ramp or channelized entering lane from the
adjacent through lane(s) intersect each other. | |
Timed Exit Gate Operating Modea mode of operation where the exit gate descent at a
grade crossing is
based on a predetermined time interval. | |
Toll Bootha shelter where a toll attendant is stationed to collect tolls or
issue toll tickets. A toll booth is located adjacent to a toll lane and is
typically set on a toll island. | |
Toll Islanda raised island on which a
toll booth or other
toll collection and related equipment are located. | |
Toll Lanean individual lane located within a toll plaza in which a
toll payment is collected or, for toll-ticket systems, a
toll ticket is issued. | |
Toll Plazathe location at which tolls are collected consisting of a grouping
of toll booths, toll islands, toll lanes, and,
typically, a canopy. Toll plazas might be located on highway mainlines or
on interchange ramps. A
mainline toll plaza is sometimes referred to as a barrier toll
plaza because it interrupts the traffic flow. | |
Toll-Ticket Systema system in which the user of a toll road receives a ticket
from a machine or toll booth attendant
upon entering a toll system. The ticket denotes the user's point of
entry and, upon exiting the toll system, the user surrenders the
ticket and is charged a toll based on the distance traveled between
the points of entry and exit. | |
Toolbox meetingToolbox meetings are typically short (10 to 30 minutes), and are held on a regular basis (weekly, or daily) to discuss safety rules, procedures, hazards, corrective actions, mishaps, and injury and illness prevention [Hinze 1997: p. 106]. | |
Trafficpedestrians,
bicyclists, ridden or herded animals, vehicles, streetcars, and other
conveyances either singularly or together while using for purposes
of travel any highway or private road open to
public travel. | |
Traffic Control Devicea sign, signal, marking, or other device used to regulate, warn, or guide traffic, placed on, over, or adjacent to a street, highway, private road open to public travel, pedestrian facility, or shared-use path by authority of a public agency or official having jurisdiction, or, in the case of a private road open to public travel, by authority of the private owner or private official having jurisdiction. | ||
TRAFFIC CONTROL DEVICE (TCD)All signs, signals, markings, and other devices use to regulate,
warn, or guide traffic. | |
Traffic Control Signal (Traffic Signal)any highway traffic signal
by which traffic is alternately
directed to stop and permitted to proceed. | |
Traffic control supervisorA person designated by the contractor to assume overall
responsibility for the safety of the work zone setup and
conformance of the temporary traffic control
devices with the TCP. | |
Traffic space | |
Trainone or more locomotives coupled, with or without cars, that operates on rails or tracks and to which all other traffic must yield the right-of-way by law at highway-rail grade crossings. | |
TRANSITION AREAWhere traffic is moved out
of normal traffic paths and into
a temporary path around the work space. It
commonly contains channelization tapers used to shift
or close the travel lane(s) or to close the shoulder. | |
Transverse Markingspavement markings that are generally placed perpendicular and
across the flow of traffic such as
shoulder markings;
word, symbol, and arrow
markings; stop lines; crosswalk lines;
speed measurement
markings; parking space markings; and others. | |
Traveled Way | |
TRBTransportation Research Board | |
Truck-mounted attenuator(TMA)A safety appliance mounted on the rear of a truck that dissipates the energy of a rear-end collision. | |
TRUCK-MOUNTED ATTENUATORS (TMA)Truck-mounted attenuators (TMAs) are energy absorbing devices
attached to the rear of a heavy vehicle. They are used
on equipment located in advance of workers or work
equipment to reduce the severity of rear-end crashes from errant
vehicles. A TMA
may be used on a
work vehicle, protection vehicle or
shadow vehicle. | |
TTCtemporary traffic control | |
TTCPA temporary traffic control plan (TTCP) describes temporary traffic control measures to be used for facilitating road users through a work zone. . . . [The plan] may range in scope from being very detailed, to simply referencing typical drawings contained in [the MUTCD], standard approved highway drawings and manuals, or specific drawings contained in contract documents" [FHWA 2000 (MUTCD: Section 6C.01)]. | |
TUBULAR MARKERS Tubular markers are channelization devices that are cylindrical in shape with a weighted base. | |
Turn Baya lane for the exclusive use of turning vehicles that is
formed on the approach to the
location where the turn is to be made. In most cases where turn
bays are provided, drivers who desire to turn must move out of a
through lane into the newly formed turn bay in order to turn. A
through lane that becomes a turn lane is considered to be a
dropped lane rather
than a turn bay. | |
Typical Applicationto be added when found | ||
U |
|---|
U.S.United States | |
U.S.C.United States Code | |
Upstreama term that refers to a location that is encountered by traffic prior to a
downstream location as
it flows in an "upstream to downstream" direction.
For example, "the upstream end of a lane line separating the turn
lane from a through lane on the approach to an
intersection" is the
end of the line that is furthest from the intersection. | |
Urban Streeta type of street normally
characterized by relatively low speeds, wide
ranges of traffic volumes,
narrower lanes, frequent intersections and
driveways, significant pedestrian traffic, and more
businesses and houses. | |
USDOTUnited States Department of Transportation | |
UVCUniform Vehicle Code | |
V |
|---|
Vehicleevery device in, upon, or by which any person or property can be
transported or drawn upon a highway, except trains
and light rail transit operating in exclusive or semi-exclusive
alignments. Light rail transit equipment operating in a mixed-use
alignment, to which other traffic is not
required to yield the right-of-way by law, is a vehicle. | |
Vibrotactile Pedestrian Devicean accessible pedestrian
signal feature that communicates, by touch, information about
pedestrian timing
using a vibrating surface. | |
Visibility-Limited Signal Face or Visibility-Limited Signal Sectiona type of signal face or
signal section
designed (or shielded, hooded, or louvered) to restrict
the visibility of a signal indication from
the side, to a certain lane or lanes, or to a certain distance from
the stop line. | |
VPH or vphvehicles per hour | |
W |
|---|
Walk Interval | |
Warning Beacona beacon used only to
supplement an appropriate warning or regulatory sign or
marker. | |
Warning Lighta portable, powered, yellow, lens-directed,
enclosed light that is used in a temporary traffic control
zone in either a steady burn or a flashing mode. | |
Warning Sign | |
Warranta warrant describes a threshold condition based upon average or
normal conditions 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 device
or other improvement is justified. Warrants are not a substitute
for engineering judgment.
The fact that a warrant for a particular traffic control device
is met is not conclusive justification for the installation of the
device. | |
Wayside Equipmentthe signals, switches, and/or control devices for railroad or light rail transit operations housed within one or more enclosures located along the railroad or light rail transit right-of-way and/or on railroad or light rail transit property. | |
Wayside Horn Systema stationary horn (or series of horns) located at a grade crossing that is
used in conjunction with train-activated or
light rail transit-activated warning systems to provide audible
warning of approaching rail traffic to
road users on the
highway or pathway approaches to
a grade crossing, either
as a supplement or alternative to the sounding of a locomotive horn. | |
WORK COMMENCEMENTThe start of work activity in or along the road. | |
WORK SPACE | |
WORK VEHICLEAny vehicle in the work
area or work zone (mobile operations)
conducting work. Examples include sweepers, rollers, paver,
striping truck, one-ton utility truck, and supervisor’s pickup
truck. | |
WORK ZONEAn area identified by advance warning where road construction, repair, utility or maintenance work is being done by workers on or adjacent to a highway, regardless of whether or not workers are present. The work zone begins with the initial advance warning sign (e.g. ROAD WORK AHEAD) and ends at the END ROAD WORK sign; or the last TCD (Traffic Control Device), or where traffic resumes normal operations. | ||
Workera person on foot whose duties place him or her within the
right-of-way of a street, highway, or pathway, such as
street, highway, or pathway construction
and maintenance forces, survey crews, utility crews, responders to
incidents within the street, highway, or pathway right-of-way,
and law enforcement personnel when directing traffic, investigating
crashes, and handling lane closures, obstructed roadways, and
disasters within the right-of-way of a street, highway, or pathway. | |
Worker on foot | |
Wrong-Way Arrow | |
Y |
|---|
Yellow Change Intervalthe first interval following the
green or flashing arrow
interval during which
the steady yellow signal indication is
displayed. | |
Social networks