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Traffic Control Terminology

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Daily Vehicle Traffic
The amount of vehicle traffic accumulated over a 24-hour period, traversed along a public road by motorized vehicles, excluding active construction equipment.

Dangerous Goods Carrier
A commercial goods carrier which transports goods deemed dangerous by the relevant provincial and federal legislation.

Deceleration Lane
A speed change lane for the purpose of enabling a vehicle that is to make an exit from a roadway to slow to the safe speed on the exit after it has left the main stream of traffic.

Decorative Municipality Identification Display Signs
Placed in the highway right-of-way, typically with supplementary vegetative plantings, to identify and advertise a municipality.

A vertical and/or horizontal change in the course or path of a vehicle as the result of a physical feature of a roadway. For example, a Speed Hump deflects the wheels, suspension and chassis of a vehicle in a vertical direction. A traffic circle requires that the vehicle be steered from its straight path to manoeuvre past the feature.

One, or a combination of several types of devices (excluding Guide Signs) that regulate, warn, or provide tracking information and guidance to drivers.

Delineation Technique
Refers to methods chosen to accomplish effective delineation. Selection of an appropriate marking material and method of application are part of a delineation technique.

Delineation Treatment
Refers to the higher-level decision process of designing delineation to be installed. Issues such as use of raised pavement markers and post markers are part of delineation treatment.

Small, Retroreflective devices erected in a series adjacent to the edge of a traveled portion of the roadway for the purpose of providing positive driver guidance.

Demand Detector
A device for indicating the presence or passage of vehicles including sensor device, lead-in cable and detector sensor (amplifier) unit.

Demand Responsive Transit
Non-fixed-route service utilizing vans or buses with passengers boarding and alighting at pre-arranged times at any location within the system's service, area. Also called "Dial-a-Ride".

The number of vehicles per kilometre per lane on the traveled way at a given instant.

Density (Traffic Signal)
A measure of the concentration of vehicles usually stated as the number of vehicles per kilometre per lane.

Design Capacity
A capacity selected for the purposes of design, usually related to a desired level of service.

Design Hour
The ranked hour in the year, in which the design hourly volume occurs,. The design hour is sometimes taken as the hour in which the thirtieth highest hourly volume in the year occurs.

Design Hourly Volume (DHV)
The hourly volume for which a road or Traffic Signal is to be designed.

Design Incoming Vehicle (DIV)
The selected vehicle or vehicles with the size and mass which correspond to a certain proportion of the vehicle population, or to a defined level of protection, used in the determination of Buffer Vehicle mass and Boll-ahead Distances for the design of construction and maintenance work zones.

Design Speed
A speed selected for purposes of design and correlation of those features of a highway, such as curvature, superelevation, and sight distance, upon which the safe operation of vehicles is dependent.

Design Vehicle
The selected vehicle or vehicles with the size, dimensions, performance, and turning characteristics which correspond to a certain proportion of the vehicle population (such as 85th percentile or worst case conditions) for road design purposes.

Detection Zone (Traffic Signal)
That area of the roadway within which a vehicle will be detected by a vehicle detector.

Detector (Traffic Signal)
A device for indicating the presence or passage of vehicles including sensor device, lead-in cable and detector sensor (amplifier) unit.

Detector Loop (Traffic Signal)
A detector that senses a change in inductance of its inductive sensor loop caused by the passage or presence of a vehicle in the detection zone of the loop.

Detector Memory (Traffic Signal)
The retention of an actuation for future utilization by the controller unit.

Detector Mode (Traffic Signal)
A term used to describe the operation of a detector channel output when a presence detection occurs-.

(1) Pulse Mode - Defector produces a short output pulse when detection occurs.

(2) Controlled Output - The ability of a detector to produce a pulse that has a predetermined duration regardless of the length of time a vehicle is in the detection zone.

(3) Continuous-presence Mode - Detector output continues if any vehicle (first or last remaining) remains in the detection zone.

(4) Limit-presence Mode - Detector output continues for a limited period of time if vehicles remain in the detection zone.

A diversion from the usual travelled roadway-, either a crossover from one multi-lane roadway to another (within the highway right-of-way), or a Route Detour.

Detour Marker
A sign used to identify a Route Detour for detour route continuity, to assist driver navigation.

Device (Traffic Calming)
A physical feature of the roadway, constructed for the purpose of affecting the movement of motor vehicles, bicycles and/or pedestrians.

Device (Traffic Control)
See Traffic Control Device.

Design Hour Volume.

Diagrammatic Sign
A sign, used primarily on freeways, which uses graphics to display the approximate geometry of the interchange or intersection, including lane configuration, along with essential directional information.

Diamond Grade Material
A non-metalized, high reflectivity micro-prismatic sign sheeting material. The material may be fluorescent or non-fluorescent.

Dilemma Zone
The roadway approach area to a signalized intersection (or other signal device) in which it is unclear to the driver, when the amber clearance interval appears, whether it is safer to attempt to stop before the stop line or to proceed through the intersection.

Directional Closure (Traffic Calming)
The intrusion of the curb, approximately to the Centreline of a roadway, to obstruct (prohibit) one direction of travel.

Directional Distribution
The directional split of traffic during the Peak or Design Hour, commonly expressed as percent in the peak and off-peak flow directions.

Directional Dividing Line
A yellow Pavement Marking indicating the division of the roadway between traffic travelling in opposite directions.

Directional Guide Sign
A broad class of signs providing route-finding or operational guidance to road users, including direction to specific destinations.

Display (Traffic Signal)
A display consists of the total illuminated and non-illuminated signals facing the motorists. "Display" is interchangeable with "Indication".

Distributed Control System
A traffic control system with distributed processor capacity. The processor capacity is distributed within the system, separated upon different nodes. Each node ought to be occupied with its own separate task. The communication between different nodes in a distributed control system consists of both data messages (from gauges etc.), and different kinds of administrative messages. As a consequence, the complexity of a Distributed Control System can be a lot higher than for a Centralized Control System.

The dividing of a single stream of traffic into separate streams.

Diversion Route
A route where a driver is required to depart completely from the normal route and is directed to use an alternate route.

To redirect traffic, typically through the use of physical obstructions or Regulatory Signs.

A raised barrier placed diagonally across an intersection which forces traffic to turn rather than proceed straight through. A diverter effectively creates two separate roadways with no access between them for motor vehicles.

Divided Highway
A multi-lane highway consisting of roadways for opposing traffic which are separated by an unpaved area or other physical barrier, including a curbed island. See also Continuous Wide Median.

Dynamic Message Sign.

U.S. Department of Transportation.

Double Line
A Pavement Marking used on two-way, undivided roadways to inform the driver of a "no-passing" zone in both directions of travel.

Downloading (Traffic Signal)
The transmission of data from a master or central computer system to a Slave or a Remote Controller Unit.

The direction that traffic is going to.

Dynamic Route Guidance Systems.

Driver Response
The driver action taken as a result of reading a traffic sign or encountering another traffic control device.

A private road giving access from a public way to a building or property on abutting grounds.

In Temporary Conditions, the length of time for specific construction, maintenance or utility work activities to take place, and for which specific requirements and typical layouts apply. See Mobile Operations, Very Short Duration, Short Duration, and Long Duration.

Dwell (Traffic Signal)
The interval portion of a phase when present timing requirements have been completed. "Rest" as in "rest in green".

Dynamic Message Sign (DMS)
An array of sign technologies that have the capability of displaying different messages to suit changing conditions on the roadway. Included within the family of dynamic message signs are full matrix displays, single line or character matrix displays, multiple pre-set message displays and simple on-off or "blankout" displays. The terms "Changeable" and "Variable" are used in the OTM to describe specific sub-sets of Dynamic Message Signs. See OTM Book 10.


A right to use or control the property of another for designated purposes:

(1) Drainage - for directing the flow of water;

(2) Planting - for reshaping roadside areas and establishing, maintaining, and controlling plant growth thereon:

(3) Scenic - for conservation and development of roadside views and natural features, -

(4) Sight Line - for maintaining or improving the sight distance:

(5) Slope - for cuts and fills

(6) Access - to utility corridor for maintenance and repair

Edge Line
A painted line marking the edge of the roadway.

A way of exiting or travelling away from a location. Is used when describing which vehicle movements may be permitted at an intersection (such as with an egress-only barrier). Is used when describing the location of driveways and walkways which provide an exit from a property.

Eighty-fifth (85th) Percentile Speed
The speed at, or below which, 85% of motorists are travelling.

Electronic Changeable Message Sign
See Changeable Message Sign.

Electronic Toll System
Systems that allow drivers to pay tolls electronically, generally through use of a Transponder. Also known as Electronic Toll and Traffic Management (ETTM).

Electronic Toll and Traffic Management (ETTM)
See Electronic Toll System.

Embedded Detector
Traffic detector system that consists of sensors in or below the surface of the roadway.

With regard to road works, an emergency is an unforeseen, unplanned combination of circumstances or the resulting situation that calls for immediate action in order to prevent or reduce damage or hazard to road users, workers, or infrastructure. In an emergency, short duration traffic control provisions should be implemented to the greatest extent practicable, including adequate reflectorization if at night, in order to avoid the creation of additional hazard.

Unauthorized use of highway right-of-way or easements for signs, fences, buildings, etc., unless authorized by encroachment permit.

Encroachment Permit
See Encroachment.

Engineering Grade Material
A retroreflective sign sheeting material meeting ASTM
Specification for Type I material or CGSB
Specification 62-GP-11 M for Reflectivity Level 11

Epoxy Thermoplastic Paint.

Electronic Toll and Traffic Management Systems. See Electronic Toll System.

Used in traffic engineering to describe a driver's anticipation of upcoming road design and traffic control conditions. Driver expectancy is usually affected by previous experience and the consistency and continuity of traffic control devices encountered. Violation of driver expectancy should be avoided whenever possible.

A divided arterial highway for through traffic with full or partial control of access and generally with grade separations at major intersections.

Extendible Portion (Traffic Signal)
That part of the green interval in an actuation phase following the initial portion which may be exceeded by traffic actuations to the Maximum Green.


The construction and/or assembly of a traffic control device and/or its supports.

Farm Tractor
A self-propelled vehicle designed and used primarily as an implement for drawing ploughs, mowing machines and other implements of husbandry and not designed or used for carrying a load.

See Movement (Traffic Signal).

Feeder Road
See Collector Road.

U.S. Federal Highway Administration.

Fibre Optic Signs
Fibre optic signs are light emitting signs that utilize a halogen bulb light source and fibre optic cable to illuminate the pixels, which are lenses coupled with shutters that either let the light through or block the light from being displayed.

Field Advertising
Commercial advertising signs located off the highway right-of-way, or, in bush country, located on, and at the edge of, the highway right-of-way.

Fixed Route
Service provided on a repetitive, fixed-schedule basis along a specific route with vehicles stopping to pick up and deliver passengers to specific locations-, each fixed-route trip serves the same origins and destinations, unlike demand responsive and taxicabs.

Flasher (Traffic Signal)
A device used to open and close signal circuits at a repetitive rate.

Movement of traffic:

(1) Interrupted - Non-continuous movement of traffic
(2) Uninterrupted - Continuous movement of traffic.

Fluorescent Orange and Yellow-Green
Fluorescent sign sheeting colours designed for high conspicuity in daytime. Fluorescent sign sheeting may be non-reflective (daytime use only) or reflective (daytime and nighttime use).

Freeway Management Systems.

Force Off (Traffic Signal)
A command to the Controller Unit that will force the termination of the current right-of-way (green) interval during the extendible portion.

A multi-lane Divided Highway with continuous dividing median, full control of access and interchanges in place of At-grade Intersections, and a posted speed of 90 km/h or greater. This term includes Toll Highways built to a freeway configuration.

Freeway Traffic Management System
A system of electronic devices, including some or all of detectors, communication system, Central Computer with management software, Changeable Message Signs, closed circuit television cameras, and incident detection, installed for the purpose of managing traffic flow on a Freeway.

Fringe Parking
An area for parking usually located outside the Central Business District and most often used by suburban residents who work or shop downtown.

Frequency Shift Keying.

FTMS Full Closure (Traffic Calming)
A raised barrier extending across the entire width of a roadway, which obstructs all motor vehicle traffic movements.

Fully Actuated (Traffic Signal)
(1) a fully actuated mode of operation is one in which both the side (minor) road and the main (major) road utilize detection devices. During operation, if no actuation occurs at the intersection, the controller will rest either in the last phase actuated or return to the main road green to rest (recalled to main road green)

(2) a fully actuated mode of operation can be one in which the passage loops are used on all approaches, or on one of the roads if the other has detection at the intersection.


Gap Reduction (Traffic Signal)
A controller feature whereby the unit extension or allowed time spacing between successive vehicle actuations on the phase displaying the green in the extendible portion of the intervals is reduced after each extension, usually in proportion to another parameter. Time waiting gap reduction is a feature whereby the unit extension in the Phase having the green is reduced in proportion to the time vehicles have waited on the phase having the red.

Freeway Traffic Management Systems.

When referring to roadway design, geometry refers to the physical characteristics and dimensions of parts of the roadway.

Glass Beads
Spheres used in conjunction with traffic paint to produce retroreflectivity in pavement markings.

Global Positioning System (GPS)
A system of satellites used for identifying earth locations. This system is now commonly used to track the position of vehicles in transit.

The area between and immediately adjacent to two merging or diverging roadways: the area may be painted or unpainted.

Grade Crossing
A railroad crossing a highway at the same elevation (no vertical separation).

Grade Separation
The vertical separation of two or more intersecting roadways or a roadway and another transportation mode, e.g., railroad, thus permitting traffic on all roads to cross traffic on all other roads without interference.

Gross Axle Weight
That part of the gross vehicle weight in kilograms transmitted to the highway by an axle unit.

Gross Vehicle Weight
The total weight in kilograms transmitted to the highway by a vehicle or combination of vehicle and load. This is not the same as the Registered Gross Vehicle Weight, which is a licensed measure.

Guide Rail
A fence or barrier to guide and help restrain vehicles from leaving the roadway.

Guide Sign
A Traffic Sign used to direct traffic along a route towards a destination.

Highway Advisory Radio.

Hazard Marker
See Object Marker.

Hazardous Materials
Materials that are considered dangerous if the transport of such goods might cause harm, risk, peril, or other evil to people, environment, equipment or any property whatsoever.

Highway Capacity Manual.

The spatial distance or time interval between the front ends of vehicles moving along the same lane or track in the same direction.

HELP (Heavy Vehicle Electronic License Plate.)
A a non-profit partnership between motor carriers and government agencies. HELP's mission is to develop and deploy advanced technology systems that create a cooperative operating and regulatory environment which improves the efficient and safe movement of commercial vehicles and the performance of highway systems.

High Intensity Material
A retroreflective sign sheeting material meeting ASTM Specification for Type III or higher or CGSB Specification 62-GP-11 M for Reflectivity Level I material.

High Occupancy Free, Others Toll (HOT) Lane Exclusive roadway or lane identified as a reserved facility for HOVS, on which a travel fee is charged for non-HOVs.

High Occupancy Vehicle (HOV)
A vehicle that carries a defined minimum number of persons (typically two or three).

High Occupancy Vehicle (HOV) Lane
Exclusive roadway or lane limited to high-occupancy vehicles, such as buses, vanpools, carpools and emergency vehicles. Some road authorities also permit motorcycles.

High Occupancy Vehicle (HOV) Management
The collective application of physical facilities to support HOV operation including HOV lane, park-and-ride lots, park-and-pool lots, and/or other supporting facilities.

A general term denoting a public way for purposes of vehicular and pedestrian travel, including the entire area within the Bight-of-way. This includes King's Highways, regional and county roads, rural roads, municipal roads and streets.

Highway Advisory Radio (HAR)
A low-powered radio (generally AM) station devoted to presenting travel-related information to the public.

Highway Delineator
One of a series of short posts with reflective heads or chevrons, used to indicate horizontal alignment.

Hold (Traffic Signal)
A command to the controller unit which causes it to retain the existing right-of-way (green) interval.

HOT Lane
High Occupancy Free, Others Toll Lane.

High Occupancy Vehicle.

Human Factors
The consideration of human physical, perceptual and mental limitations in engineering design, so as to optimize the relationship between people and things. The objective is to reduce error and increase user comfort.

Hybrid Sign
A light-emitting VMS which combines Fibre Optic or LED-based technologies with reflective flip-disk technology When pixels are activated, the electromechanical shutter rotates to display the reflective surface of the disk and the light source through an opening in the shutter for the illuminated pixel. The display of fluorescent yellow sheeting on the open shutter enhances the visibility of the display under direct sunlight.

Inductive Loop Detection.

Luminous flux incident per unit of area (direct light).

An incident may be any of the following: traffic collision, stalled vehicle, load spillage, or other action that affects one or more lanes of traffic. A collision typically involves a moving vehicle striking or being struck by another vehicle, person, or object.

Incident Detection Algorithm
Computer software developed to automatically identify incidents on the basis of field data received from detection equipment.

Indication (Traffic Signal)
The illumination of a traffic signal lens or combination of signal lenses at the same time. See Display.

Inductive Loop Detector
Coil of cable embedded in the pavement surface that creates a magnetic field. A vehicle is detected when this magnetic field is disturbed.

Information Load
The amount of information presented to a driver by a sign or other traffic control device, which is a factor in determining the amount of time drivers require to read, comprehend, and act upon the message.

A way of entering or travelling into a location. Is used when describing which vehicle movements may be permitted at an intersection (such as ingress-only barriers). Is also used when describing the location of driveways and walkways which provide access into a property.

Initial Portion (Traffic Signal)
The first timed part of the green interval of an actuated phase.

The process or act of placing, erecting, and/or connecting a traffic control device or system into its functional position and state of operational readiness.

Integrated Pedestrian Facility
Facilities where pedestrians are integrated with other road users, where special measures must be taken to control pedestrians and other road users, to ensure that pedestrians are protected.

Intelligent Transportation Systems (ITS)
A wide range of advanced electronics and communications technologies applied to roads and vehicles, designed to improve safety and decrease congestion. When the term is applied to transit, it is called APTS: in commercial trucking, it is referred to as CVO.

Intelligent Vehicle-highway Systems (IVHS)
See Intelligent Transportation Systems (ITS).

A system of interconnecting roadways in conjunction with one or more grade separations, providing for the interchange of traffic between two or more roadways on different levels.

Interchange Types
(1) Cloverleaf - A full cloverleaf is a four-quadrant interchange with an inner loop for left turns and a direct outer connection for right turns in each quadrant. A partial cloverleaf is a two quadrant interchange where loops are provided in two quadrants, and traffic exits from the main road on a single ramp for both left and right turns-,

(2) Diamond - A four-leg interchange with a single one-way ramp in each quadrant. All left turns are made directly on to or off of the minor highway-,

(3) Directional - An interchange, generally having more than one highway grade separation, with direct connections for the major left turning movements.

A term referring to a connecting service or roadway between two or more adjacent municipalities and their suburban areas.

Interconnected Controller (Traffic Signal)
A controller which operates traffic control signals under the supervision of a master controller.

Interconnection (Traffic Signal)
(1) A means of remotely controlling some or all of the functions of a traffic control signal-,

(2) An electronic, fibre optic, time synchronization, radio, telephone or electrical connection with coordination units or modems in the controller cabinets-, the physical interconnection.

Interdictory Symbol
An annular (circular) red band with a diagonal red stroke at 45 degrees, or as close to 45 degrees as practical, signifying that whatever is depicted within the symbol is prohibited.

Not continuous. As used for traffic control devices, usually means regularly spaced either in time (flashing beacon) or space (broken pavement lines). Otherwise, may mean regularly or irregularly spaced (such as intermittent hazard).

Used to denote transfer points for travel by more than one mode.

The area embraced by the prolongation of lateral curb lines or, if none, of the rights-of-way of two or more highways that join one another at an angle, whether or not one highway crosses the other.

Intersection Approach
That part of an intersection leg used by traffic approaching the intersection.

Intersection Channelization
Raised or painted islands at an intersection that prevent specific movement(s) from being made or provide better definition of large uncontrolled areas of pavement.

Intersection Leg
That part of any one of the roadways radiating from the intersection which is close to the intersection but outside the area of the intersection proper.

Intersection Sight Distance
The distance at which a driver on the roadway approaching an intersection can see vehicles on the other intersection legs to the left and right of the path of travel. May also be referred to as Vision Triangle.

Interval (Traffic Signal)
A part of a phase that is individually timed by the controller unit.

Interval Sequence (Traffic Signal)
The order of appearance of Signal Indications during successive intervals of a cycle.

Intersection Pedestrian Signals.

Institute of Transportation Engineers.

Intelligent Transportation Systems.

Intelligent Vehicle Highway Systems.

In-Vehicle Information Systems.


A measure of distance equal to 1,000 m (.622 miles).

King's Highway
A highway, including secondary and tertiary roads designated under the Public Transportation and Highway Improvement Act.

Video monitors mounted on a cabinet, in a wall, or on a counter top which travellers can access to request travel-related information.

Kiss and Ride
A place where commuters are driven and dropped off or picked up at a station to board, or alight from, respectively, a public transportation vehicle. (Also Kiss I ' Ride.)


A defined width of road intended to accommodate a single line of moving vehicles.

Lane Closure
Closing of a highway lane to road users.

Lane Designation Sign
An overhead or ground-mounted sign, erected at or in advance of an intersection, or over a lane or lanes, to regulate traffic on an approach by assigning certain traffic movements to specific lanes or a reserved lane. These signs should not be confused with Turn Control Signs.

Lane Line
A Pavement Marking, other than a Directional Dividing Line, which separates two traffic lanes assigned to traffic moving in the same direction.

Lane Use Sign
See Lane Designation Sign.

Large Arrow Sign
A Warning Sign intended to inform drivers of a sharp change in roadway alignment (e.g., Wa-108, TC-7 and TC-12).

Lateral Intrusion Deterrence Gap (LIDG)
The gap between a buffer vehicle and the work area to discourage lateral vehicle intrusions into a closed lane upstream of a stationary work area, or the gap between buffer vehicle and work vehicle (and between buffer vehicles) to discourage lateral vehicle intrusions into a lane in which mobile work operations are taking place.

See Longitudinal Buffer Area.

Lane Control Signs.

The practice of installing lane closures using two or more installers, whereby one installer installs barrels up to where the previous (second) installer started, then drives beyond (leapfrogs) the second installer, leaving a gap in the closure, to resume installation of the closure downstream. When the second installer reaches the point where the first installer resumed installation, he leapfrogs the first installer, and the process is repeated. This procedure should not be used.

Light Rail (LRT)
An electric railway with a "light volume" traffic capacity compared to "heavy rail". Light rail may use shared or exclusive right-of-way, high or low platform loading, and multi-car trains or single cars. Also known as Streetcar, Trolleycar, and Tramway.

Live Lane
A roadway lane open to traffic. It includes a traffic lane where vehicles, though they may be present, are being diverted away from a stationary or mobile work activity by work vehicles or Buffer Vehicles equipped with Traffic Control Devices, such as a TC-12.

Loadswitch (Traffic Signal)
A device used to switch 120 volt power to the traffic control signal heads. Loadswitches are normally semiconductor devices which are switched by a low voltage signal from the controller unit.

Local Road
A street or road primarily for access to residence, business or other abutting property.

Left-turn Lane
A lane reserved for left-turning vehicles and so designated by Pavement Markings and/or lane-use signs.

Left-turn Slip-around
An additional lane or width of pavement provided for through traffic to separate this traffic from left-turning traffic at an intersection,

Legal Authority
The authority provided, by legislation and regulation, to a jurisdiction or enforcement body for the actions it takes.

Sign legibility is governed by the distance at which the sign becomes legible and the duration for which it remains legible. Legibility depends on character height, font style and spacing, contrast ratio and the spacing of characters, words and lines.

Legibility Distance
The distance at which a sign can be read by a given driver under prevailing conditions.

Legibility Distance, Required
The distance at which a sign must be legible, based on the travel speed and the sum of Reading Time, Perception-reaction Time, and Manoeuvre Time.

Level of Service
A term which, broadly interpreted, denotes any one of an infinite number of differing combinations of operating conditions that may occur on a given lane or roadway when it is accommodating various traffic volumes. Level of service is a qualitative measure of the effect of a number of factors, which include speed and travel time, traffic interruptions, freedom to manoeuvre, safety, driving comfort and convenience,

Local Traffic
Traffic which originates from or is destined to a location within a Neighbourhood.

Logo Services Signing
Logo-based signing located on freeways, on approaches to interchanges, for specific food, fuel and accommodation (lodging) services and establishments.

Long Duration (LD) Work
Stationary maintenance, construction, or utility activities which require a separate work space for longer than 24 hours. See also Short Duration (SD) and Very Short Duration (VSD) work.

Longitudinal Buffer Area (LBA)
The fourth component of a stationary work zone, downstream from the transition area and upstream of the work area, which provides protection for traffic and workers, by providing errant vehicles an opportunity to brake to a halt between the end of the transition area and the work space.

Level of Service.

Low Volume/High Volume Road
For Temporary Conditions, low volume roads are defined as those with a combined traffic volume in both directions of less than 3,000 vehicles per day. Conversely, high volume roads are those with a combined traffic volume of 3000 vehicles per day or more.

Left Turn Lane.

Metal or hard rubber studs or ridges on tires used to improve traction on dirt surfaces.

The luminous flux in a light ray, emanating from a surface or falling on a surface, in a given direction, per unit of projected area of the surface as viewed from that direction, per unit of solid angle. (Reflective light.)