Glossary - mme.gov.qa

FINAL DRAFT JUNE 2014 – NOT TO BE USED FOR DESIGN PURPOSE

Glossary

QHDM GLOSSARY

GLOSSARY PAGE 1 FINAL DRAFT JUNE 2014 – NOT TO BE USED FOR DESIGN PURPOSE

Glossary

Accessibility

1. A measure of mobility.

2. Total travel time between areas weighted by the relative attractiveness of the destination.

3. A measure of the ability of public transportation users to access transit modes.

Accuracy

1. The closeness or degree of agreement, within a stated tolerance and probability of conformity, between a quantity measured or estimated and an accepted reference value.

2. The degree to which a measurement, or the mean of a distribution of measurements, tends to coincide with the true population mean.

Active Frontage

The frontage or edge of a building or space that has windows and doors, as opposed to blank walls, fences, and garages.

Acquisition

The process of obtaining right-of-way.

Addendum

A contract revision developed between advertising and opening proposals.

Alignment

1. The fixing of points on the ground in correct linear form for setting out, for example, a road, railway, wall, transmission line, or canal.

2. A ground plan showing a route (as opposed to a profile section) including levels and elevations.

All-red period

Period during the change from one phase to the next when all signal aspects display a red light signal.

Approach

1. A set of lanes accommodating all left-turn, through, and right-turn movements arriving at an intersection from a given direction.

2. Section of the accessible route that flanks the landing of a curb ramp. The approach may be slightly graded if the landing level is below the elevation of the adjoining sidewalk.

Approach half-width (v)

The total width of the traffic lanes on the approach to a roundabout, upstream from any entry flare. This is used by some capacity models to estimate the capacity of the roadway in advance of the roundabout.

QHDM GLOSSARY

PAGE 2 GLOSSARY FINAL DRAFT JUNE 2014 – NOT TO BE USED FOR DESIGN PURPOSE

Approved Departure

A departure that meets the Overseeing Organization’s requirements for that element of the works, provided that any mitigation measures proposed by the design organization or conditional to that approval are incorporated into the design and works.

Aquifer

A geologic formation, group of formations, or part of a formation capable of yielding a significant amount of groundwater to a well or springs.

Ashghal

Qatar Public Works Authority (PWA).

At-grade intersection

An intersection where all roadways join or cross at the same level.

Attenuation Tank

Storage tank to arrest stormwater flows.

Auxiliary Lane

The portion of the roadway adjoining the through traveled way for parking, speed change, turning, storage for turning, weaving, truck climbing, or for other purposes supplementary to through traffic movement.

Average annual daily traffic (AADT)

The total annual volume of traffic passing a point or segment of a highway in both directions divided by the number of days in a year.

Average daily traffic (ADT)

The total volume during a given time period, in whole days, greater than one day and less than 1 year, divided by the number of days in the time period.

Axle

A supporting shaft or member on, or with which, a wheel or set of wheels revolves. The number of vehicle axles is commonly counted in pairs sharing the same axis. For example, a car is classified as having only two axles.

Axle load

The total load transmitted by all wheels, the centers of which may be included between two parallel transverse vertical planes 1 m apart, extending across the full width of the vehicle.

Back Slope

The slope from the bottom of a swale to the existing ground surface; also referred to as cut slope.

QHDM GLOSSARY


Bank

The side slopes or margins of a channel between which the stream or river is normally confined. More formally, the lateral boundaries of a channel or stream, as indicated by a scarp, or on the inside of bends, by the streamward edge of permanent vegetal growth.

Barchan dune

A large, crescent-shaped dune at right angles to the prevailing wind and having a steep, concave leeward side with the crescent tips pointing downwind.

Barrier

A device used to prevent a vehicle from striking a more severe obstacle or feature located on the roadside or in the median or to prevent crossover median crashes. As so defined, there are four classes of traffic barriers: roadside barriers, median barriers, bridge railings, and crash cushions.

Base Course

The layer or layers of specified or selected material of designed thickness placed on a subbase or subgrade to support a surface course.

Batter

The deformation of the surface of the head of the rail in the immediate vicinity of the end.

Bearing

A support element transferring loads from the superstructure to the substructure while permitting limited movement capability.

Bedrock

The scour-resistant material underlying erodible soils and overlying the mantle rock, ranging from surface exposure to depths of several hundred kilometers.

Berm

1. A narrow shelf or ledge; also a form of dike. A more detailed description might be (a) the space left between the upper edge of a cut and the toe of an embankment or (b) a horizontal strip or shelf built into an embankment to break the continuity of an otherwise long slope. Also may be the top surface or plane of a shoulder, ledge, or bank constructed in connection with the road.

2. A raised, elongated area of earth intended to direct the flow of water, visually screen, redirect out-of-control vehicles, or reduce noise levels by shielding the highway; may also be a horizontal ledge in an earthen bank to increase stability of a steep slope.

3. Earthwork used to redirect or slow down impinging vehicles or vessels and to stabilize fill, embankment, or soft ground and cut slopes.

BES 6001

The Buildings Research Establishment (BRE) Environmental and Sustainability Standard for responsible sourcing of construction products.

QHDM GLOSSARY


Bike path

A way or separated part of a road provided for the sole use of cyclists.

Bicycle

A vehicle propelled solely by human power upon which any person may ride, having two tandem wheels, except scooters and similar devices.

Binder course

A plant mix of graded aggregate (generally open graded) and bituminous material that constitutes the lower layer of the surface course.

Blackspot

A road location with an abnormally high number of crashes. This term is said to derive from the method that was originally used to identify locations with a high number of crashes. These crashes were pinpointed on a physical map using colored pins to represent the severity of each crash. Black was reserved for crashes having caused property damage only, and the significant proportion of these crashes created black areas or spots at crash concentration points.

Borehole

A general term for a small diameter hole sunk in the ground, usually vertically but may be horizontal or inclined, to collect samples of soil, rock strata, and groundwater and to carry out tests to establish the properties of the strata.

Borrow

Suitable material from sources outside the roadway prism, used primarily for embankments.

Braking distance

Distance a vehicle travels between when the brakes are applied and when the vehicle stops.

Breakaway

A design feature that allows a device such as a sign, luminaire, or traffic signal support to yield or separate upon impact. The release mechanism may be a slip plane, plastic hinges, fracture elements, or a combination of these.

Bridge

A structure spanning and providing passage over a river, chasm, road, or railroad.

Building height

The height of a building expressed in terms of a maximum number of floors; a maximum height of parapet or ridge; a maximum overall height; any of these maximum heights in combination with a maximum number of floors; a ratio of building height to street or space width; height relative to particular landmarks or background buildings; or strategic views.

QHDM GLOSSARY


Building line

The line formed by the frontages of buildings along a street. The building line can be shown on a plan or section.

Bus

A self-propelled, rubber-tired vehicle designed to carry a substantial number of passengers, commonly operated on streets and highways.

Bus lane

A lane of roadway intended primarily for use by buses, either all day or during specified periods. Also known as a transit priority lane or bus priority lane.

Bus shelter

A shelter for patrons at a bus stop. Usually located at high loading points, shelters may provide seating and protection from the weather.

Bus stop

A waiting, boarding, and alighting area usually designated by distinctive signs and by curbs or road markings.

Bypass

An arterial highway that permits traffic to avoid part or all of an urban area.

Calibration

The process of comparing model parameters with real-world data to ensure that the model realistically represents the traffic environment. The objective is to minimize the discrepancy between model results and measurements or observations.

California Bearing Ratio (CBR)

The ratio of the force needed to penetrate a soil mass with a 5-centimeter-diameter circular piston to the force needed to penetrate a mass of high-quality crushed stone with the same piston.

Cantilever

A support, either horizontal or vertical, supplied at one end only.

Capacity

Ability of the junction form, its design features, and operating characteristics to accommodate traffic demand from all approaches.

CAPEX

Capital expenditure; a business expense incurred to create future benefit.

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Capillary break layer

Spacing left wide enough between two layers to prevent water moving through capillary action.

Capillary rise

The upward movement of water molecules along the surface of a solid.

Capping layer

The layer replacing existing material under the pavement.

Carrier drain

A sealed pipe for the conveyance of surface water.

Carrier filter drain

A fully or half-perforated pipe used to collect and convey surface water and subsoil water to an outfall.

Catchment area (A)

A defined area, determined by topographic features, drainage patterns, and land use, within which all rain will contribute runoff to a specific point or system.

Civil Engineering Environmental Quality Assessments System (CEEQUAL)

Originally developed as a sustainability and environmental performance assessment system. CEEQUAL International has been developed to adapt to non-United Kingdom environments globally.

Center lane

Traffic lane between the right- and left-hand lanes.

Centerline

A line indicating the division of the roadway between traffic moving in opposite directions.

Central island

The raised island at the center of the roundabout. On single-lane roundabouts, the central island may include a truck apron, allowing larger vehicles to negotiate the roundabout while maintaining an adequate entry path radius.

Channelization (or channelizing)

1. Use of traffic islands or road markings to direct traffic into specific traffic lanes.

2. Straightening, deepening, or both, of a channel by such means as artificial cutoffs, flow-control measures, river training, or diversion of flow into an artificial channel.

3. The separation or regulation of conflicting traffic movements into definite paths of travel by traffic islands or pavement markings to facilitate the orderly movements of vehicles and pedestrians.

QHDM GLOSSARY


Channelizing island

A curbed, raised island used to control and direct conflicting traffic, usually turning.

Character assessment

An area appraisal that identifies distinguishing physical features, including historical and community associations.

Characteristic value parameters

Soil parameters that are defined as being a cautious estimate of the value affecting the occurrence of the limit. This is analogous to moderately conservative parameters.

Circulatory roadway

The one-way roadway on a roundabout that surrounds the central island.

Circular traffic

Vehicular traffic flowing around a circular system or a roundabout.

Clear zone

The unobstructed, relatively flat area provided beyond the edge of the travelled way for the recovery of errant vehicles. The clear zone includes any shoulders or auxiliary lanes.

Closed-circuit television (CCTV)

Video cameras that transmit signals to a defined, specific, limited set of monitors.

Cloverleaf interchange

A four-leg interchange that employs loop ramps to accommodate left turns. A full cloverleaf has ramps for two turning movements in four quadrants; all other cloverleafs are referred to as partial cloverleafs.

Cohesiveness

A harmonious grouping of complementary elements. For example, a cohesive townscape contains objects and architectural elements that have a consistent overall effect.

Colebrook-White Equation

A method for determining flows in conduits, such as pipes or open channels; most appropriate for flows in smoother bore pipes.

Collector

A road of the intermediate functional category that serves a small town directly, connecting it to the arterial network.

Collector channel

A system of channels that collects and conveys surface water.

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Collector-distributor road

A one-directional road used to reduce or eliminate weaving by reducing the number of conflict points on the mainline while satisfying the demand for access to and from the mainline.

Commercial vehicle

A vehicle with heavy-duty chassis and suspension designed for commercial freight or passenger haulage.

Community

The general public or the people who will be affected by proposals either as end users or as local people who live or work in the area. In the context of engagement, community will also include people who travel through the study area or who visit or spend leisure time there.

Community Engagement

A process of involving the general public, or the people who will be affected by road building or improvement, in the design process.

Community Severance

Community severance occurs where road traffic speed or volume inhibits access to goods, services, or people.

Compaction

The process by which the asphalt mix is compressed and reduced in volume.

Compound curve

A curve that consists of two or more arcs of different radii curving in the same direction and having a common tangent or transition curve between them.

Cone penetration test (CPT)

An in situ test to determine the geotechnical engineering properties of soil and to delineate soil stratigraphy. The test method consists of pushing an instrumented cone, with the tip facing down, into the ground at a controlled rate.

Connectivity

The ability of a transportation network to provide service to the maximum number of origin-and destination trip pairs through the optimal integration of routes, schedules, fare structures, information systems, and modal transfer facilities.

Consultation

When the project team provides options for discussion and listens to comments from stakeholders and the wider community.

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Context

The character and setting of an area described in terms of physical, economic, and social characteristics.

Contingency

A markup applied to account for substantial uncertainties in quantities, unit costs, and the possibility of currently unforeseen risk events related to quantities, work elements, or other project requirements.

Continuing professional development (CPD)

A register of courses, conferences, workshops, and other training undertaken with the purpose of keeping road safety auditors up to date with the latest developments in road safety auditing, crash investigating, and road safety engineering.

Contract

The written agreement between the contracting agency and the contractor setting forth the obligations of the parties thereunder for the performance of the prescribed work.

Contractor

The individual, partnership, firm, corporation, or any acceptable combination thereof, or joint venture, contracting with whom an agency or owner enters into agreement for performance of prescribed work.

Controller

Apparatus that controls and switches traffic signals.

Corridor

1. A strip of land between two termini within which traffic, topography, environment, and other characteristics are evaluated for transportation purposes. Also for transmission of a utility.

2. A broad geographical band that identifies a general directional flow of traffic. It may encompass streets, highways, and transit alignments.

Crash

A rare random multifactor event when a vehicle collides with another vehicle, pedestrian, animal, road debris, or stationary obstruction, such as a tree or utility pole. Traffic crashes may result in injury, death, vehicle damage, and property damage.

Crash investigation

The collection and examination of historical crash data over a period of time in order to identify patterns, common trends, and factors that may have contributed to the crashes.

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Crashworthy

1. A feature that has been proven acceptable for use under specified conditions through either crash testing or in-service performance.

2. 2. A system that has been successfully crash tested to a currently acceptable crash test matrix and test level or one that can be geometrically and structurally evaluated as equal to a crash-tested system.

Cross slope

The transverse slope of the roadway cross section measured perpendicular to the direction of travel, also referred to as crossfall.

Cross section

A vertical section of the ground and roadway at right angles to the centerline of the roadway, including all elements of a highway or street from right-of-way line to right-of-way line.

Crossfall

The transverse slope of the roadway cross section measured perpendicular to the direction of travel, also referred to as cross slope..

Crossroad

At-grade intersection of crossing of the two roadways.

Crown

1. The top or highest point of the internal surface of the transverse cross section of a pipe.

2. The shape of a tangent roadway cross section with a high point in the middle and a cross slope downward toward both edges.

Culvert

Any structure under a roadway with a clear opening of 6.1 meters or less measured along the center of the roadway.

Curb

A structure with a vertical, horizontal, or sloping face placed along the edge of a pavement or shoulder forming part of a gutter, and strengthening or protecting the edge.

Curb extension

A section of sidewalk extending into the roadway at an intersection or midblock crossing that reduces the crossing width for pedestrians and may help reduce traffic speeds.

Cycle

A complete sequence of traffic signal indications.

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Cycle crossing

Place on a roadway marked to indicate where cyclists should cross.

Dahal

A cavity in limestone or gypsum rock strata.

Dam

A barrier to confine or raise water for storage or diversion or to create a hydraulic head.

Decision tracking form (DTF)

A formal record of the identified risks, ratings, and recommendations from the road safety audit together with the designer’s response and comments and endorsement by the project manager, the Overseeing Organization, and the Overseeing Organization safety engineer.

Deck

A component, with or without wearing surface, that supports wheel loads or pedestrian loads directly and is supported by other components.

Defect

A failure to meet a requirement with respect to a single quality characteristic.

Deflection

1. The vertical movement occurring between the supports of a bridge superstructure or its components (beams, girders, and slabs) that results from their own weight and from dead and live loads. Although all parts of a structure are subject to deflections, usually only those deflections that occur in the superstructure are of significance during construction.

2. The change in the path of a vehicle imposed by geometric features of a roundabout, resulting in a slowing of vehicles.

Deformation

A change in structural geometry due to force effects, including axial displacement, shear displacement, and rotations.

Delay

The increased travel time experienced by a person or vehicle due to circumstances that impede the desirable movement of traffic. It is measured as the time difference between actual travel time and free-flow travel time.

Density

The floor space of a building or buildings or some other unit measure in relation to a given area of land. Built density can be expressed in terms of plot ratio (for commercial development); number of units or habitable rooms per hectare (for residential development); site coverage plus the number of floors or a maximum building height; or a combination of these.

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Departure determination

The Overseeing Organization’s formal acceptance for inclusion or rejection of the design organization’s application for a Departure from Standards.

Departure determination report (DDR)

The analysis of the standards advisor on the proposed Departure from Standards and recommendations as to whether or not the departure should be approved. The DDR also sets out any additional mitigation measures that are considered essential to mitigate the effects of the proposed departure.

Departure from Standards

A situation when the compliance requirements in the Qatar Highways Design Manual are not achieved in the design. Before incorporating a Departure from Standards into the works, the designer shall seek the approval of the Overseeing Organization.

Design build

The project delivery method that combines the design and construction phases of a project into a single contract.

Design criteria

Criteria, coupled with prudent judgmental factors that are used in design.

Design hour volume

A volume determined for use in design representing traffic expected to use the highway. Unless otherwise stated, it is an hourly volume.

Design life

The number of years of intended service life of a facility before the first major rehabilitation.

Design organization

The organization(s) commissioned to undertake the various phases of project preparation. Refers to any organization undertaking the design of works that affect the highway network, including public and private developments.

Design phase

The effort (budget/cost) of taking a project through the planning, scoping, and design phases. The terms design or design phase are sometimes used interchangeably with preliminary engineering.

Design speed

A selected speed used to determine the various geometric design features of the roadway. The selected design speed should be a logical one with respect to the topography, anticipated operating speed, adjacent land use, and functional classification of the highway.

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Design team

Qualified professionals within the design organization responsible for the road project design and implementation.

Design team leader

A person within the design team who is responsible for managing the road project design and coordinating the input of the various design disciplines.

Design vehicle

A vehicle, with representative weight, dimensions, and operating characteristics, used to establish highway design controls for accommodating vehicles of designated classes.

Design volume

A volume, determined for use in design, representing traffic expected to use the highway. Unless otherwise stated, it is an hourly volume.

Design-bid-build

The traditional project delivery method for building highways and making highway improvements where the agency sequentially designs the project, solicits bids, and awards the construction contract to the lowest responsive bidder (construction contractor) to build the project.

Desire line

A straight line on a map that connects the origin and destination of a trip and that shows by its width or density the volume of trips between that origin and destination pair.

Detector

A part of vehicle-detecting equipment that, when traversed by a vehicle, initiates the process of detection; usually laid in a roadway.

Diagraphy drilling

Drilling using destructive techniques with real-time data acquisition such as depth, drilling rate, rotation, torque, thrust pressure, retaining pressure, injection fluid flow rate and pressure, x and y inclination, and reflected vibration.

Diamond interchange

A four-leg interchange with a single one-way ramp in each quadrant. All left turns are made directly onto or off the minor highway.

Directional ramp

An one- or two-way connector road carrying free flowing traffic within an interchange between one level or direction and another, or both.

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Director

The responsible person in the Overseeing Organization with overall responsibility for the road project.

Discharge rate

Volume of water per second passing out of the system at a specific point.

Divided roadway

A two-way roadway on which the opposing traffic lanes or travel lanes are separated by a median.

Divisional island

An island introduced on undivided highway intersections to alert drivers to the crossroad ahead, separate opposing traffic, and regulate traffic through the intersection.

Dowel

A reinforcing bar embedded in two concrete sections that transfers stresses and holds the sections together.

Downstream

The part of the roadway where traffic flows away from the section in question.

Drainage

1. The process of removing surplus groundwater or surface waters by artificial means.

2. The manner in which the waters of an area are removed.

3. The area from which waters are drained.

4. A drainage basin.

Drainage basin

A part of the surface of the earth that is occupied by a drainage system, that consists of a surface stream or a body of impounded surface water together with all tributary surface streams and bodies of impounded surface water.

Drainage systems

A system designed to limit water damage to the roadway by controlling or directing the free flow of water over, under, or adjacent to the highway and to control the movement of water through the pavement's structural support where necessary.

Driveway

An access from a public way to adjacent properly.

QHDM GLOSSARY


Dropped curb

A combined ramp and landing to accomplish a change in level at a curb. This element provides street and sidewalk access to pedestrians using wheelchairs. Also known as a curb ramp.

Earth pressure

The soil pressure on abutments and other components of a bridge against which any significant depth of earthen fill rests.

Earthwork(s)

1. The work of excavating, raising, or sloping the ground.

2. The civil engineering process that includes extraction, loading, transport, transformation or improvement, placement, and compaction of natural materials (soils, rocks) and secondary or recycled materials, or both, to obtain stable and durable cuttings, embankments, or engineered fills.

3. Structures that are formed by the excavating, raising, or sloping of ground, such as embankments, cuttings, or remediated natural slopes.

Earthworks balance

Having a similar volume of earthworks cut materials and fill materials on a construction project.

Easement

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

Edgeline

A line that indicates the edge of the traveled way.

Effluent

Sewage, water, or other liquid, partially or completely treated or in its natural state as the case may be, flowing out of a reservoir, basin, or treatment plant.

Embankment

A structure of soil, soil aggregate, or broken rock between the embankment foundation (supporting ground) and the subgrade.

Emergency flood area

Area used to safely contain large and sudden accumulations of stormwater; this is additional to any sustainable drainage systems.

Enclosure

The use of buildings to create a sense of defined space.

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Engagement plan

A document setting out the process of stakeholder and community engagement for the project. This should state who would be involved, how, and when.

Entry angle (φ)

The angle at which vehicles entering the roundabout merge with vehicles on the circulatory roadway. At smaller roundabouts where there is insufficient spacing between the entry and exit arms for a vehicle to join the circulatory roadway, the angle may be measured relative to the adjacent exit.

Entry radius (r)

The minimum radius of the right curb line at the entry.

Entry path radius (a)

A measure of the deflection to the right imposed on vehicles entering a roundabout; used to control vehicle entry speeds.

Equivalent axle load (EAL)

The number of a determined standard axles causing the same damage effect as a given axle configuration of different magnitude.

Equivalent single- or standard-axle load (ESAL)

A numerical factor that expresses the relation of a given axle load to another axle load in terms of their effect on serviceability of a pavement structure.

Exemption

Exception from the road safety audit requirements. Road projects that make no significant change to the characteristics of the road may have an exemption.

Exemption certificate

Documentary evidence recording the decision not to undertake a road safety audit; endorsed by the Overseeing Organization Safety Engineer.

Exploratory holes

A general term for boreholes sunk by various means including cable percussion, rotary coring, rotary open holing, trial pits, and trial trenches to determine subsurface characteristics.

Exit radius

The minimum radius of the right curb line at an exit.

Expressway

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

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Facies

The sum total of features, such as sedimentary rock type, mineral content, sedimentary structures, bedding characteristics, and fossil content, that characterize a sediment as having been deposited in a given environment.

Fill

Material used to raise the level of a low area.

Filter drain

A linear drainage feature, consisting of a trench filled with permeable materials, designed to capture and convey surface water.

Filter membrane

A type of geotextile that allows the unimpeded flow of water through its surface but prevents the passage of silt and other small particles, thereby prolonging the life of drainage medium, such as in filter drains.

Flare

1. The variable offset distance of a barrier to move it farther from the traveled way, generally in reference to the upstream end of the barrier.

2. Sloped surface that flanks a curb ramp and provides a graded transition between the ramp and the sidewalk. Flares bridge differences in elevation and are intended to prevent ambulatory pedestrians from tripping. Flares are not considered part of the accessible route.

Flexible pavement

A pavement structure that maintains intimate contact with and distributes loads to the sub grade and depends upon aggregate interlock, particle friction, and cohesion for stability.

Flood

Inundation of the road and surrounding areas with stormwater, or effluent from a burst pipe.

Flora

All members of the plant kingdom: higher ferns, ferns and fern allies, mosses and liverworts, algae and phytoplankton, fungi and lichens.

Ford

A location where a highway crosses a channel by allowing high annual or larger flows to pass over the highway and lower flows to pass through a culvert(s). Often used with cutoff walls, roadway lane markers, and paved roadway embankments. Warning signs may be included.

Fore slope

The slope from the edge of the shoulder to the bottom of the swale, also referred to as fill slope.

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Foundation

A supporting element that derives its resistance by transferring its load to the soil or rock supporting the bridge.

Functional Classification

The grouping of streets and highways into classes, or systems, according to the character of service they are intended to provide.

Gantry

A crane or hoisting machine mounted on a frame or structure spanning an intervening space

Gateway

Points through which a road project passes during the project life cycle.

Geoenvironmental practitioner

A person specializing in geoenvironmental engineering.

Geometric design

Highway design that deals with dimensions and relationships of such features as alignments, profiles, grades, sight distances, clearances, and slopes; distinguished from structural design, which is concerned with thickness, composition of materials, and load-carrying capacity.

Geophysical survey company

A specialist contractor who carries out geophysical survey work.

Geosynthetic

Polymeric products generally used in civil engineering construction. This includes eight main product categories: geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells, and geocomposites.

Geotechnical design

The use of scientific principles, technical information, and thought in the definition of the ground engineering aspects a structure, earthwork, or system to perform specified functions with the maximum economy and efficiency.

Geotechnical engineering

The application of the sciences of soils and rock mechanics and engineering geology in building, civil engineering construction, and the protection of the environment.

Geotechnical hazard

Unfavorable ground or groundwater conditions that may pose a risk to construction or of adverse performance of completed works.

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Geotechnical practitioner

A person specializing in geotechnical engineering or engineering geology.

Geotechnical risk

The risk posed to construction or to the appropriate function of completed works caused by ground or groundwater conditions at the site.

Geotechnical risk register

A live and continuously updated table or spreadsheet that provides an up-to-date record of the project geotechnical risks. The register usually contains a description of the risk, an assessment of its likelihood and consequences, proposed mitigation measures, and owners.

Geotextile

Any permeable knitted, woven, or non-woven textile material integral to a project, structure, or system.

Geographic information system (GIS)

A computer-based system that stores information based on geographical coordinates.

Grade Separation

Any structure that provides a traveled way over or under another traveled way.

Grade-separated roundabout

A category of roundabout that incorporates at least two bridges within the layout

Gradient

Change of elevation, velocity, pressure, or other characteristics per unit length; slope.

Ground investigation

The process by which geological, geotechnical, and other relevant information is obtained for a project.

Ground investigation company

A company that specializes in services such as borehole drilling in soils and rock and laboratory testing.

Ground investigation factual report

The document that presents the results of a ground investigation. The report will normally include the records of borehole and trial pits, soils and rock, and laboratory testing.

Ground model

A conceptual model based on the geology and morphology of the site, and used to speculate on likely ground and groundwater conditions and variability.

QHDM GLOSSARY


Groundwater

1. Subsurface water occupying the saturation zone from which wells and springs are fed. A source of base flow in streams. In a strict sense, the term applies only to water below the water table.

2. Water at and below the groundwater table; basal or bottom water; phreatic water. Used also in a broad sense to mean all water below the ground surface.

3. Water in the ground that is in the zone of saturation from which wells, springs, and groundwater runoff are supplied.

Groundwater table

The level below which the ground is saturated with water; the elevation of this layer varies seasonally and spatially.

Gully

A chamber covered by a grating, which allows surface water to enter a drainage system.

Gutter

That portion of the roadway section adjacent to the curb that is used to convey stormwater runoff.

Hard strip

Hard strip is an extra width of the roadway pavement along the edge of the travelled way built contiguous to and with the same pavement structure as the roadway pavement.

Health and safety

Activities or processes that focus on the prevention of death, injury, and ill health to those at work and those affected by work activities.

Heritage/Historic Assets

A building, monument, site, place, area or landscape identified as having a degree of significance because of its heritage interest.

Hertz

The rate at which sound oscillates; measured in cycles per second.

Hierarchy

The grouping of individual highways in a highway system, according to their purpose or function, the type of traffic they serve, and maintenance.

Highway

A public way for purposes of vehicular travel, including the entire area within the right-of-way.

QHDM GLOSSARY


Highway capacity

The maximum sustainable flow rate at which vehicles or persons reasonably can be expected to traverse a point or uniform segment of a lane or roadway during a specified time period under given roadway, geometric, traffic, environmental, and control conditions; usually expressed as vehicles per hour, passenger cars per hour, or persons per hour.

Highway drainage system

A system of pipes and drains that collect and transport surface water runoff from highways.

Horizontal alignment

Direction and course of the center line of a road or roadway on plan.

Horizontal curve

Curve in plan of a road.

Hydraulic radius

1. The cross sectional area of a stream divided by its wetted perimeter.

2. The cross sectional area of a stream of water (normal to flow) divided by the length of that part of its periphery in contact with its containing conduit; the ratio of area to wetted perimeter.

3. A measure of the boundary resistance to flow, computed as the quotient of cross sectional area of flow divided by the wetted perimeter. For wide shallow flow, the hydraulic radius can be approximated by the average flow depth.

Hydrology

The science and study concerned with the occurrence, circulation, distribution, and properties of the waters of the earth and its atmosphere, including precipitation, runoff, and groundwater.

Hyetograph

1. Graphical representation of rainfall intensity over time.

2. A graph plotting rainfall amounts or intensities during various time increments versus time.

3. A graphical representation of average rainfall, rainfall-excess rates, or volumes over specified areas during successive units of time during a storm.

Information Sharing

A level of engagement with stakeholders and the community. When participation or consultation are not practical/appropriate, or where there is a need to communicate an important message, the project may need to focus on a process of information sharing.

Impact severity

A measure of the impact severity of a vehicle of mass M, impacting at a speed V, at an impact angle ϴ. It is defined as follows: IS = 1/2 M(V Sin ϴ)2.

QHDM GLOSSARY


Impermeable surface

Surfaces in which texture is such that water cannot move perceptibly through it under pressures ordinarily found in subsurface water.

Infiltration

1. The volume of groundwater entering a sewer and its connections from the soil through pipe, joints, connections, or appurtenances.

2. The flow of a fluid into a substance through pores or small openings.

Information sharing

A level of engagement with stakeholders and the community. When participation or consultation is not practical or appropriate, or where there is a need to communicate an important message, the project may need to focus on a process for information sharing.

InfoWorks CS

Urban drainage network modeling software.

Inland

A segment along an inland river consisting of terminals, fleeting areas, and related cargo facilities, designated as a port for reference purposes and, in limited instances, for tonnage compilation.

Inscribed circle diameter (ICD)

The diameter of the outside edge of the circulatory roadway; in cases where the roundabout is non-circular, the local value in the region of the entry is used. This is the basic parameter used to define the size of a roundabout.

Inside lane

1. The lane on a multi-lane divided roadway adjacent to the median.

2. The lane on an undivided roadway adjacent to the centerline of the roadway.

3. The right most lane on the inside of the curve adjacent to the right shoulder on an undivided roadway, in the direction of traffic.

4. The left most lane on the inside of the curve adjacent to the median shoulder on a divided roadway, in the direction of traffic.

Intensity

The rate of rainfall upon a watershed; usually expressed in millimeters.

Interchange

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

2. The exchange of cars between railroads at specified junction points.

QHDM GLOSSARY


Intergreen period

The period between the end of the green light signal giving right-of-way for one phase and the beginning of the green light signal giving right-of-way for the next phase.

Interim road safety audit

A road safety audit applied to the whole or part of a road project during design and construction. An interim road safety audit is not mandatory and is not a substitute for the formal Stage 1, 2, 3, and 4 Road Safety Audits.

Interim road safety audit file

A file containing copies of all communications between the design team, the road safety audit team, and the project manager. The file is only required for road projects where the road safety audit team undertakes an interim road safety audit.

Intersection

The general area where two or more highways join or cross, within which are included the roadway and roadside facilities for traffic movements in that area.

Intersection angle

The angle between two intersection legs.

Intersection leg (arm)

Any one of the highways radiating from and forming part of an intersection. The common intersection of two highways crossing each other has four legs

Intersection point

Point at which two successive straight lengths of road, or tangents to curves, intersect.

Interstate Highway System

A system of in the United States that connects principal metropolitan areas, cities, and industrial centers.

International Roughness Index (IRI)

An index computed from a longitudinal profile measurement using a quarter-car simulation at a simulation speed of 80 kilometers per hour.

Irrigation

The application of water to land to assist in the production of crops and other plants; treated sewage effluent is commonly used for irrigation in Qatar and, as such, there is a low risk of contact with pathogens.

QHDM GLOSSARY


Island

A defined area between traffic lanes used to control vehicle movements. Islands may range from an area delineated by a raised curb to a pavement area marked out by paint or thermoplastic markings.

Intelligent transportation system (ITS)

Programs intended to apply advanced communication and control technologies to ground transportation. Formerly referred to as intelligent vehicle highway systems.

Junction approach

The section of road upstream from a junction. The fully compliant visibility provision is considered most essential and may be increased. The length of the junction approach is dependent on design speed.

Junction approach sight distance

The sight distance requirement within a junction approach. At higher design speeds, the junction approach distance is greater than the stopping sight distance. Refer to Part 3, Roadway Design Elements.

k-value

Modulus of subgrade reaction; measured in pounds per cubic inch.

Land use

The physical characteristics of the land surface and the human activities associated with the land surface.

Landmark

A building or structure that stands out from its background by virtue of height, size, or some other aspect of design.

Landscape

The character and appearance of land, including its space, form, ecology, natural features, colors, and elements that combine in a way that is distinctive to particular localities, the way they are perceived, and the area’s cultural and historical associations. Landscape character can be expressed through landscape appraisals, maps, or plans. A “townscape” describes the same concept.

Lane

A strip of roadway used for a single line of vehicles.

Lane capacity

Traffic capacity of one traffic lane.

QHDM GLOSSARY


Lane line

A line separating two lanes of traffic traveling in the same direction.

Lane numbers

The numbering used to identify lanes on multi-lane roadways; Lane 1 is the inside lane, and Lane X is the outside lane.

Layout

The way buildings, routes, and open spaces are placed in relation to each other.

Left lane

The lane of a multi-lane highway on the extreme left side of the roadway in the direction of travel.

Left-turn lane

Diverging lane or left-hand lane used solely for traffic turning left.

Legibility

The degree to which people can understand, traverse, and identify with the built environment.

Leq

Equivalent continuous sound level. An average of the time-varying sound energy for a specified period.

Level of service (LOS)

A qualitative measure describing operational conditions within a traffic stream based on service measures such as speed, travel time, freedom to maneuver, traffic interruptions, comfort, and convenience.

Likelihood

The probability of a risk occurring.

Limit state

The state beyond which a structure or earthwork no longer fulfils the relevant design criteria. The two most common limit states are ultimate limit state and serviceability limit state. BS EN 1997-1, Eurocode 7. Geotechnical design. General rules, defines ultimate limit state as “states associated with collapse or with other similar forms of structural failure”, and it defines serviceability limit state as “states that correspond to conditions beyond which specific service requirements for a structure or structural member are no longer met.”

Liquefaction

Loss of soil strength with a quicksand-like behavior that is caused by cyclic loads produced by vibrating machinery or earthquakes.

QHDM GLOSSARY


Local distinctiveness

The positive features of a place and its communities that contribute to its special character and sense of place.

Local road or street

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

Local traffic

Freight moving solely over the lines of a single carrier.

Longitudinal

The direction associated with the axis of the main structural busses or girders in the bridge.

Loop

A one-way turning roadway that curves about 270 degrees to the right to accommodate a left turn from the through roadway. It may include provision for a left turn at a crossroad terminal.

Luminaire

Complete lighting unit, consisting of one or more lamps including the parts designed to distribute the light, to position and protect the lamps, and to connect the lamps to the electric power supply.

Mainline

The roadway carrying the main flow of traffic; generally traffic passing straight through the intersection or interchange.

Maintaining authority

The authority responsible for operating and maintaining the completed road.

Maintenance

The preservation of the entire highway, including surface, shoulders, roadsides, structures, and the traffic-control devices necessary for safe and efficient use.

Major system

Surface water trunk sewer network, surface water pumping stations, groundwater control networks, and surface water storage and retention areas and tanks.

Manhole

An opening in an underground system that workers may enter for the purpose of making installations, removals, inspections, repairs, connections, and tests.

Manning’s equation

A method for determining flows in conduits, such as pipes or open channels. The method is most appropriate for flows in rough open channels.

QHDM GLOSSARY


Manual count

Measurement of traffic characteristics based on human observation; may be electronically recorded.

Massing

The combined effect of the arrangement, height, volume, and shape of a building, or group of buildings.

Mast arm

An approximately horizontal supporting arm designed to hold a sign, signal head, or luminaire.

Median

The portion of a highway separating opposing directions of the traveled way.

Merge

To move into a traffic stream.

Midblock crossing

A crossing point within a block rather than at an intersection.

Mini-roundabout

A category of roundabout that incorporates a small, raised central island that is fully traversable by large vehicles.

Minor street

The street controlled by stop signs at a two-way stop-controlled intersection. Also referred to as side street.

Minor system

Road drainage, comprising gullies, soakaways, ditches, connecting pipework, and storage areas required prior to connection to the major system.

Moderately conservative parameters

Engineering parameters that are the geotechnical practitioner’s conservative best estimate considering the natural variation in the soil or rock properties.

Moisture content

An indication of the amount of water contained in a material; usually expressed as a percentage of the weight of the oven-dry material weight.

Motorcycle

A two-wheeled motorized vehicle having one or two saddles and sometimes a sidecar with a third supporting wheel.

QHDM GLOSSARY


Mounting height

Minimum vertical distance to the bottom of a sign or traffic signal, or to the center of gravity of a luminaire, relative to the pavement surface.

Movement

People and vehicles going to and passing through buildings, places, and spaces. The movement network can be shown on plans, by space syntax analysis, by highway designation, by figure ground diagrams, through data on origins and destinations or pedestrian flows, by desire lines, by details of public transport services, by walk bands, by details, or by bike paths.

Mushtarak

Shared-use access streetscape.

Natural surveillance

The discouragement to wrongdoing by the presence of passers-by, or the ability of people to be seen out of surrounding windows. Also known as passive surveillance or passive supervision.

Network

1. A system of links and nodes that describes a transportation system.

2. The configuration of highways or transit routes and stops that constitutes the total system.

Node

A place where activity and routes are concentrated, often used as a synonym for junction.

Nonmotorized users (vulnerable road user)

Pedestrians, cyclists, and equestrians, including mobility impaired.

Nose

An approximately triangular paved area between a ramp and the mainline at a merge or diverge, suitably marked to discourage drivers from crossing it.

Observational method

A method in which the design and risks are reviewed in a planned manner during construction and in response to the monitored performance of a structure or earthwork.

Occupant impact velocity

Velocity, relative to the vehicle in motion, at which a hypothetical point mass occupant impacts a surface of a hypothetical occupant compartment.

Offtracking

The difference in the paths of the front and rear wheels of a vehicle when performing a turning maneuver.

QHDM GLOSSARY


Operational expenditure (OPEX)

Ongoing costs to run a business or project.

Outfall

Point of discharge from a pipe or channel system.

Outside lane

1. The lane on a multilane divided or undivided roadway adjacent to the right shoulder in the direction of the traffic.

2. The lane on the outside of a curve adjacent to the right shoulder, in the direction of traffic.

Overpass

A grade separation where a highway passes over an intersecting highway or railroad.

Overseeing Organization

The highway authority responsible for approving a road construction or improvement project, including planning, design and implementation, road safety, Departures from Standard. The Overseeing Organization can delegate these roles to an appointed project management consultant.

Overseeing Organization safety engineer

A person from the Overseeing Organization who has responsibility for road safety engineering for road projects that the Overseeing Organization is responsible. This includes endorsement of decision tracking forms and Exemption Certificates and the methodology used by the road safety audit teams.

Overtaking sight distance

The distance required for a driver to complete a passing or overtaking maneuver without coming into conflict with the oncoming traffic, on a two-way two-lane undivided roadway, also referred to as passing sight distance.

Participation

The process of working closely with stakeholders and the community to develop ideas and solutions collaboratively, giving a genuine opportunity for involvement in the project development process.

Passenger

A person who rides a transportation vehicle, excluding the driver or the crewmembers of a public transportation vehicle.

Passenger car

A motor vehicle, other than a motorcycle, designed for carrying 10 or fewer passengers and used for the transportation of persons.

QHDM GLOSSARY


Passenger car equivalent

The number of passenger cars displaced by a single heavy vehicle of a particular type under specified roadway, traffic, and control conditions for use in capacity analysis.

Passing Sight Distance

The distance required for a driver to complete a passing or overtaking maneuver without coming into conflict with the oncoming traffic, on a two-way two-lane undivided roadway, also referred to as overtaking sight distance.

Pavement structure

The combination of sub-base, base course, and surface course placed on a subgrade to support the traffic load and distribute it to the roadbed.

Pedestrian Realm Zones

The pedestrian realm is the area between the curb and the property or building line. The pedestrian realm zones include the threshold, pedestrian, street furniture, cyclist, and edge zones.

Percent defective (PD)

The percentage of the lot falling outside specification limits. It may refer to either the population value or the sample estimate of the population value. Also referred to as “percent nonconforming”.

Peak flow

The most voluminous period of flow at a location during a set time, usually in the period during or directly after a storm.

Peak hour

The hour during which the maximum amount of travel occurs. It may be specified as the morning peak hour or the afternoon or evening peak hour.

Peak hour factor

1. The hourly volume during the maximum-volume hour of the day divided by the peak 15-minute flow rate within the peak hour.

2. A measure of traffic fluctuation within the peak hour.

Peak period

The period during which traffic levels rise from their normal background levels to maximum levels. These periods are for morning, evening, or mid-day peaks and include appropriate peak hours.

Peak traffic flow

Maximum traffic flow under given circumstances.

QHDM GLOSSARY


Pedestrian

A person afoot or in a wheelchair.

Pedestrian crossing (crosswalk)

Any portion of a roadway at an intersection or elsewhere distinctly indicated for pedestrian crossing by lines or other markings on the surface.

Penstock

A sliding plate that regulates flow.

Perception/reaction distance

Distance travelled during the perception/reaction time.

Perception/reaction time

Time interval between the occurrence of an event that demands immediate action by the driver and the driver’s response.

Permeability

The degree to which an area has a variety of alternative routes through it providing pleasant, convenient, and safe access for people to places.

Phase

Set of conditions that fixes the pattern of movement and waits for one or more traffic streams during a signaling cycle.

Piezocone test

A cone penetration test where pore pressure measurement is also made.

Pile

A long, heavy timber, steel, or reinforced concrete post that has been driven, jacked, jetted, or cast vertically into the ground to support a load.

Pile load capacity

The load that a pile can carry without failing; usually defined in terms of ultimate capacity and capacity such that it restricts movement within serviceability limits.

Pipeline

Pipe sections joined together.

Platoon

A group of vehicles or pedestrians traveling together as a group, either voluntarily or involuntarily, because of traffic signal controls, geometrics, or other factors.

QHDM GLOSSARY


Plans

The contract drawings that show the location, character, and dimensions of the prescribed work, including layouts, profiles, cross sections, and other details.

Police crash listings

Formally recorded details of crashes occurring on Overseeing Organization roads.

Policy

A definite course of action or method of action selected to guide and determine present and future decisions.

Ponding

The accumulation of surface water.

Porewater pressure

The pressure of groundwater held within a soil or rock.

Positive drainage

A piped system operating by gravity flow associated with an urban situation and used in conjunction with gullies, curbs, and sidewalks.

Preliminary sources study

An examination of existing information concerning a site, such as geological maps, previous borehole records, historical maps, aerial photographs, and satellite imagery, to assess ground conditions and previous land uses.

Primary signal face

The signal face nearest to and facing oncoming traffic. It is situated close to the stop line on the near side of the roadway facing the approaching traffic but may be duplicated on the off side.

Priority intersection

An unsignalized at-grade intersection at which vehicles on the minor road are required to yield to vehicles on the major road.

Program manager

The person with overall responsibility for the program and budget.

Project

The specific section of the highway together with all appurtenances and construction to be performed thereon under the contract.

Project management consultant (PMC)

The consultant appointed to manage a process or deliverable on behalf of the Overseeing Organization.

QHDM GLOSSARY


Project manager

A person from within, or appointed by, the Overseeing Organization with responsibility for the progression of a road project in accordance with the policies and procedures of the Overseeing Organization and for compliance with the requirements of the Qatar Highway Design Manual.

Proposal

The offer of a bidder to perform stated construction work at the prices quoted.

Public art

Permanent or temporary physical works or art visible to the public, whether part of the building or freestanding. The art can include sculpture, lighting effects, street furniture, paving, railings, and signs.

Public realm

The parts of a village, town, or city, including streets, squares, and parks whether publicly or privately owned, that are available without charge for everyone to use or see. Also referred to as “public domain”.

Public road

A road or street open to public travel under the jurisdiction of, and maintained by, a public authority.

Public transportation

Transportation service to the public on a regular basis using vehicles that transport more than one person for compensation, usually but not exclusively, over a set route or routes from one fixed point to another. Routes and schedules of this service may be predetermined by the operator or may be determined through a cooperative arrangement. Subcategories include paratransit and mass transit service that are available to the public. Also referred to as “public transit”.

Public/Private Interface

The point at which public areas and buildings meet private ones.

Pumping station

A facility that includes pumps, power supply, and control equipment for pumping liquids from one place to another.

R-value

The measure of the soil or aggregate resistance to displacement, as determined by ASTM International D2844, Standard Test Method for Resistance R-Value and Expansion Pressure of Compacted Soils and the American Association of State Highway and Transportation Officials, T-190, Standard Method of Test for Resistance R-Value and Expansion Pressure for Compacted Soils.

QHDM GLOSSARY


Rail

A rolled steel shape designed to be laid end to end in two parallel lines on ties to form a track for rail cars, traveling cranes, and similar vehicles.

Rainfall intensity

The amount of rainfall occurring in a unit of time, converted to its equivalent in millimeters per hour at the same rate.

Ramp

1. A short roadway connecting two or more legs of an intersection or connecting a frontage road and main lane of a highway.

2. A sloped transition between two elevation levels.

Ramp metering

A system used to reduce congestion on a freeway facility by managing flow from on-ramps. An approach ramp is equipped with a metering traffic signal that allows the vehicles to enter a facility at a controlled rate.

Reference standards

Standards of a technical society, organization, or association, including the building codes of local or state authorities, that are referenced in the contract documents.

Refuge (island)

An island at or near a pedestrian crossing or bike path that aids and protects pedestrians and cyclists who cross the roadway.

Rehabilitation

Work undertaken to restore the serviceability and to extend the service life of an existing bridge or highway.

Reinforced concrete

Structural concrete containing prestressing tendons or nonprestressed reinforcement.

Relaxation

An alternative acceptable design criterion in the Qatar Highway Design Manual; although it may not be preferred because it may affect road safety, it is introduced at the discretion of the design team leader.

Resistance factor

A factor accounting primarily for variability of material properties, structural dimensions, workmanship, and uncertainty in the prediction of resistance, but also related to the statistics of the loads through the calibration process.

QHDM GLOSSARY


Resources

The labor, equipment, and material necessary to perform work on a contract bid item or other element of work.

Restricted right-of-way

Movement in a particular direction accorded only by a green-arrow traffic signal at a primary signal face.

Resurfacing

The placing of one or more new courses on an existing surface.

Return period

An estimate of the likelihood of an event occurring. A statistical measurement, typically based on historical data, denoting the average reoccurrence interval over an extended period.

Reverse curve

Two abutting curves in a road that are of opposite hand in the shape of an “S” or its mirror image.

Rideability index (RI)

An index derived from controlled measurements of the longitudinal profile in the wheel tracks and correlated with panel ratings of rideability.

Ridedown acceleration

Acceleration experienced by a hypothetical "point mass" occupant subsequent to impact with a hypothetical occupant compartment.

Right-turn bypass lane

A lane provided adjacent to but separated from the circulatory roadway, which allows right-turning movements to bypass the roundabout.

Right lane

The lane of a multi-lane highway on the extreme right side of the roadway in the direction of travel.

Right-hand lane

Traffic lane on the extreme right in the direction of traffic flow.

Right-of-way

1. Land, property, or interest therein, usually in a strip, acquired for or devoted to transportation purposes.

2. The precedence in passing or proceeding accorded to one vehicle or person over another.

3. The legal power of passage over another person’s land.

QHDM GLOSSARY


Right-turn lane

A diverging lane or right-hand lane used solely for traffic turning right.

Rigid pavement

A pavement structure that distributes loads to the subgrade having as one course a portland cement concrete slab of relatively high bending resistance.

Risk

The chance of something happening that will have an impact on project objectives. Risk components are the probability or likelihood of failing to achieve a particular outcome and the consequences and impacts of failing to achieve that outcome.

Risk management

Systematic, analytic process to consider the likelihood that a threat will harm an asset or individuals and to identify actions that reduce the risk and mitigate the consequences of an attack or event.

Road


Road earthworks

An embankment or cutting present within the transportation system.

Road markings

Markings set into the surface of, applied upon, or attached to the pavement for the purpose of regulating, warning, or guiding traffic.

Road project

All works that involve construction of a new road or permanent change to the existing roads or features. This includes changes to the road layout, curbs, signs and markings, lighting, signaling, drainage, landscaping, and installation of roadside equipment.

Road safety audit (RSA)

A formal examination of the operational safety of an existing or future road link or intersection by an independent and suitably qualified road safety audit team. A road safety audit reports qualitatively on potential road safety issues and identifies opportunities to improve operational safety for all road users with the objective of minimizing the number and severity of personal injury crashes.

Road safety audit brief

The instructions to the road safety audit team from the Overseeing Organization or design organization defining the scope and details of the road project to be audited, including sufficient information for the road safety audit to be undertaken.

QHDM GLOSSARY


Road safety audit briefing meeting

A meeting at which all parties involved in the design and development of the road project meet with the road safety audit team to outline the scope and discuss the design ethos of the project.

Road safety audit debrief

A meeting at which the road safety audit team reports all findings from the road safety audit to those who attended the road safety audit briefing meeting.

Road safety audit report

The report produced by the road safety audit team describing the road safety related problems identified by the team and the recommended solutions to those problems.

Road safety audit team

A team of at least two people who work together on all aspects of the road safety audit. This team is independent of the design team and is approved by the Overseeing Organization safety engineer. The team shall be allocated specifically to each road project.

Road safety audit team leader

The person with the appropriate training, skills, and experience who is approved for a particular road safety audit by the project manager on behalf of the Overseeing Organization and is endorsed by the Overseeing Organization safety engineer. The road safety audit team leader has overall responsibility for carrying out the road safety audit, managing the road safety audit team, and certifying the road safety audit report.

Road safety audit team member

A member of the road safety audit team with the appropriate training, skills, and experience necessary for the road safety audit of a specific road project; reports to the road safety audit team leader.

Road safety audit team observer

A person with appropriate training, skills, and experience who accompanies the road safety audit team to observe, interact, and gain experience of the road safety audit procedure before becoming a road safety audit team member.

Road safety engineering

The process of analyzing the results of a crash investigation to design and implement physical changes to the road network to reduce the number and severity of crashes involving road users.

Road structures

Any bridge, culvert, catch basin, drop inlet, retaining wall, cribbing, manhole, endwall, building, sewer, service pipe, underdrain, foundation drain, or similar features present within the transportation system.

QHDM GLOSSARY


Road users

Any person making use of any part of a road, including pedestrians, cyclists, and drivers of vehicles.

Roadbase

The layer of specified or selected material placed on a subbase or formation.

Roadside

The area between the outside shoulder edge and the right-of-way limits. The area between roadways of a divided highway may also be considered roadside.

Roadway

The portion of a highway, including shoulders, for vehicular use. A divided highway has two or more roadways.

Roadway width

The roadway clear space between barriers, curbs, or both.

Roughness coefficient

The estimated measure of texture at the perimeters of channels and conduits. Usually represented by the "n value" coefficient used in Manning's channel flow equation. Numerical measure of the frictional resistance to flow in a channel, as in the Manning or Strickler formulas.

Roundabout

An intersection at which traffic circulates counter-clockwise around a central traffic island; traffic entering the intersection is required to yield to vehicles on the circulatory roadway.

Runoff (surface)

That part of the precipitation that runs off the surface of a drainage area after accounting for all abstractions.

Runoff coefficient (C)

The factor representing that portion of runoff that results from a unit of rainfall. It is dependent on terrain, topography, and the rate of runoff to precipitation.

Rural areas

An area that is predominantly natural with little, or no, land use development.

Rutting

The formation of longitudinal depressions in the roadway surface from traffic wear in the wheel path.

QHDM GLOSSARY


Road weather information system (RWIS)

Sensors installed in the travel lanes of the highway and airport runways that measure the temperature of the pavement. Atmospheric sensors are placed adjacent to the pavement and measure air temperature; relative humidity; wind speed and direction; precipitation type, intensity, and rate; and the driver's perception of visibility. Information is used to inform motorists and assist public agencies in maintenance decision making.

Sabkha

Sabkha are extensive salt flats that are characteristic of saline intrusion in coastal areas of Qatar. Sabkha are underlain by sand, silt, and clay that are often encrusted with salt (halite). Coastal sabkha occurs along the coast; inland sabkha are associated with isolated lagoons.

Safe system

A road safety model that compensates for human error by ensuring that road users are not subject to crash forces that result in fatal or serious injuries.

Sag

The greatest vertical distance from a horizontal line between the connections at the vertical supports to a point located on the wire.

Saline

A liquid mixture of salt and pure water; or in the context of soils, those that contain or are impregnated with salt.

Scale

The impression of a building when seen in relation to its surroundings, or the size of parts of a building or its details, particularly as experienced in relation to the size of a person. Sometimes it is sense of scale; at other times, it is the size of the elements and the way they are combined. The concept is difficult and ambiguous; often the word is used simply as a synonym for “size”.

Schedule

A listing in time sequence of every trip and every time point of each trip from open to close of service on a transit line.

Scissor intersection

At-grade intersection of two roads crossing obliquely.

Scoping

An initial stage in determining the nature and potential scale of project issues.

Scour

The washing away of streambed material by water channel flow. General scour occurs as a result of a constriction in the water channel openings; local scour occurs as a result of local flow changes in a channel due to constrictions caused by the presence of bridge piers or abutments.

QHDM GLOSSARY


Secondary signal face

The signal face facing oncoming traffic supplementing the primary signal face and beyond the stop line.

Seepage

The slow movement of water through small cracks and pores of the bank material.

Segregation

The separation of the coarse aggregate from the rest of the mix in a hot mix asphalt (HMA).

Seismic hazard

Unfavorable condition resulting from earthquake activity that may pose a risk to construction or have an adverse effect on the performance of completed works.

Seismic loading

The application of an earthquake-generated load to a structure.

Semitrailer

A freight trailer supported at its forward end by a truck tractor or another trailer and at its rearward end by attached axles.

Sense of place

The design of buildings and the definition of space that, through their uniqueness, give a location its particular identity.

Service flow rate

The maximum hourly rate at which vehicles, bicycles, or persons reasonably can be expected to traverse a point or uniform segment of a lane or roadway during a given time period (usually 15 minutes) under prevailing roadway, traffic, environmental, and control conditions while maintaining a designated level of service, expressed as vehicles per hour or vehicles per hour per lane.

Service limit state

Limit state relating to stress, deformation, and cracking applied to normal operating loads.

Service road

A road parallel to but segregated from a major road and providing direct access to adjacent land uses by distributing traffic onto higher grade roads.

Setback

The distance that a building is set back from the plot boundary, or from the nearest pavement edge.

QHDM GLOSSARY


Setting

An area of land and related features that has a material bearing on the character and amenity.

Settlement

Differential vertical displacement of slabs adjacent to a joint or crack.

Settlement pattern

The distinctive way that the roads, paths, and buildings are laid out in a particular place.

Shared-use path

A bikeway physically separated from motorized vehicle traffic by an open space or barrier and either within the highway right-of-way or within an independent right-of-way. Shared-use paths may also be used by pedestrians, skaters, wheelchair users, joggers, and other nonmotorized users. Also referred to as a “bike path”.

Sheet

A flat rolled product with a thickness between 0.15 mm and 6.35 mm.

Shift

Lateral displacement of a circular curve in a road, measured along the radius, consequent upon the introduction of a transition curve.

Shoulder

The portion of the roadway contiguous with the traveled way primarily for accommodation of stopped vehicles for emergency use and for lateral support of base and surface course.

SI

A number from 0 to 10 used to categorize crashes by the probability of their resulting in property damage, personal injury, or a fatality, or any combination of these possible outcomes. The number can then be translated into a crash cost and the relative effectiveness of alternate safety treatments can be estimated.

Sidewalk

A paved pathway that parallels a highway, road, or street and is intended for pedestrians.

Sieve

U.S. Standard Sieve, as defined in AASHTO M 92. Measure percent passing sieve sizes by weight.

Sight distance

The length of highway ahead that is visible to the driver.

Sight line

The line, in plan or in profile, that delineates the area in which a sight distance can be achieved.

QHDM GLOSSARY


Sign

A device conveying a specific message by means of words or symbols, erected for the purpose of regulating, warning, or guiding traffic.

Signal face

The side of a signal head capable of exhibiting signal lights.

Signal head

An assembly containing one or more signal lenses that control a vehicular traffic or pedestrian movement.

Signaling cycle

One complete sequence of the operation of a traffic signal.

Signalized intersection

A type of intersection where conflicting movements are separated over time by a signal that allocates right-of-way in an alternating and regular pattern for each legal movement.

Sikka

Narrow passage between properties or buildings for pedestrian only or shared pedestrian/cycle use.

Single point urban interchange

A type of diamond interchange where the diagonal ramps are placed as close as possible paralleling the freeway, so that ramp traffic in effect meets at a single point on the surface street directly below, or above, the freeway or expressway.

Single-lane roundabout

A category of roundabout that has a single lane on the circulatory roadway.

Skew angle

The angle between the centerlines of two intersecting roadways when they intersect at less than 90 degrees.

Slab

A component having a width of at least four times its effective depth.

Slip ramp

A ramp within an interchange between a mainline roadway and the lower classification network, or vice versa, that meets the lower classification network at an at-grade intersection. Traffic using a slip ramp usually has to yield/give way to traffic already on the mainline or on the lower classification network.

QHDM GLOSSARY


Slope

The relative steepness of the terrain, expressed as a ratio or percentage. Slopes may be categorized as positive (back slopes) or negative (foreslopes) and as parallel or cross slopes in relation to the direction of traffic.

Slope ratio

An arithmetic expression of vertical and horizontal value relationships of a slope. Vertical values precede horizontal values.

Split phase

Permitted movement of traffic from the same direction in one or more traffic lanes while traffic in the remaining traffic lanes is stopped.

Stone matrix asphalt (SMA)

A gap-graded hot mix asphalt.

Structural Number (SN)

A linear combination of flexible pavement components that expresses pavement design as a single number.

Soakaway

A subsurface drainage feature to which water is conveyed; designed to facilitate infiltration.

Source control

Methods of managing and reducing stormwater runoff at site level.

Spacing

The distance between two successive vehicles in a traffic lane measured from the same common feature of the vehicles.

Specialist advisor

A person approved by the project manager to provide specialized independent advice as part of the road safety audit team should the road project include complex features outside the experience of the road safety audit team members. For example, a complex traffic signal controlled intersection.

Specifications

The compilation of provisions and requirements for the performance of prescribed work.

Speed

The rate of vehicular movement, generally expressed in kilometers per hour.

Speed limit

The maximum or minimum speed applicable to a section of highway, as established by law.

QHDM GLOSSARY


Splitter island

A curbed, raised area on the approach to a roundabout, which is located and shaped to direct and separate traffic movements into and out of the roundabout.

Spoil

The material removed from an excavation or by dredging.

Stabilization

Modification of soils or aggregates by incorporating materials that increase load bearing capacity, firmness, and resistance to weathering or displacement.

Stage

Indication by traffic signals during a period of the signaling cycle that gives right-of-way to one or more particular traffic movements.

Staggered intersection

An at-grade intersection of three roads, at which the major road is continuous through the intersection and the minor roads connect with it by forming two opposed T-intersections.

Stakeholder

Any organization, representatives of an organization, or individual who is interested in or affected by a project.

Stakeholder engagement

The process of involving stakeholders in the design process.

Stakeholder mapping

A process of identifying stakeholders and assessing their level of power and influence. Stakeholder mapping is useful in defining the engagement plan.

Standard axle

A single-axle load of 8,167 kilograms.

Standard penetration test (SPT)

An in situ dynamic penetration test designed to provide information on the geotechnical engineering properties of a soil. Procedures for the test are described in BSI BS EN ISO 22476-3: 2005, Geotechnical investigation and testing. Field testing standard penetration test and ASTM International D1586-08a, Standard Test Method for Standard Penetration Test and Split-Barrel Sampling of Soils.

Standards Advisor

A consultant, independent body, or department in an Overseeing Organization providing advice, review, and recommendations on Standards.

QHDM GLOSSARY


Stopping sight distance

The minimum specified sight distance within which a vehicle travelling at a specified speed can come to a stop.

Stopping time

The time interval between the instant when the driver receives a stimulus that signifies a need to stop and the moment the vehicle comes to stop.

Storage

Water that is strategically held in a specific area.

Storage length

The length provided on an intersection approach or auxiliary lane for enabling vehicles to wait to enter the intersection without inhibiting through traffic.

Storm hydrograph

A graph that records the rate of flow through a catchment during a storm event.

Stormwater

Precipitation runoff.

Street


Street Clutter

Clutter refers to any street furniture item that is not needed because it is a redundant, poorly located, poorly designed, or a temporary item.

Street furniture

Structures, objects, and equipment installed on roads for various purposes and which contribute to the street scene (e.g., bus shelters, litterbins, seating, lighting, railings, and signs).

Streetscape

The visual elements of a street including the roadway, sidewalk, street furniture, trees, and open space that combine to form the street’s character.

Stress-absorbing membrane interlayer (SAMI)

A pavement layer consisting of rubberized asphalt concrete, chip seal, or slurry seal, or a combination of geomembrane and asphalt concrete, placed over a concrete base or pavement to retard reflective cracking of the concrete cracks and joints through the surface of new flexible pavement.

QHDM GLOSSARY


Structural number

A linear combination of flexible pavement components that expresses pavement design as a single number.

Subgrade

The top surface of a roadbed upon which the pavement structure and shoulders, including curbs, are constructed.

Superelevation

A tilting of the roadway surface to partially counterbalance the centripetal forces (lateral acceleration) on vehicles on horizontal curves.

Superpave (superior performing asphalt pavement)

A method that uses the following size definitions: Maximum size – one sieve size larger than the nominal maximum size. Nominal maximum size – one sieve size larger than the first sieve to retain more than 10 percent by weight.

Surface course

One or more layers of a pavement structure designed to accommodate the traffic load, the top layer of which resists skidding, traffic abrasion, and the disintegrating effects of climate. The top layer is sometimes referred to as the “wearing course”.

Surface runoff

That part of the runoff that travels over the soil surface to the nearest stream channel.

Surface treatment

One or more applications of bituminous material and cover aggregate or thin plant mix on an old pavement or any element of a new pavement structure.

Surface water

Water that travels across the ground and hard surfaces, such as paved roads and buildings, rather than seeping into the soil.

Surveillance

The discouragement to wrongdoing by the presence of passers-by or the ability of people to be seen from surrounding windows.

Sustainability

Identifies a concept and attitude in development that considers a site’s natural land, water, and energy resources as integral aspects of the development.

QHDM GLOSSARY


Sustainable development

Maximizing the capability to recycle components of the infrastructure and minimizing the use of nonrenewable resources.

Sustainable urban drainage systems (SuDS)

Surface water drainage systems that replicate natural systems and use cost-effective solutions with low environmental impacts to drain collect, store, and clean water before it is released slowly back into the environment.

Swale

A wide, shallow ditch usually grassed or paved and without well-defined bed and banks. A slight depression in the ground surface where water collects and may be transported as a stream. Often vegetated and shaped so as not to provide a visual signature of a bank or shore.

Swept path

The amount of roadway width that a vehicle covers in negotiating a turn that is equal to the amount of off-tracking plus the width of the vehicle.

Tack coat

An application of bituminous material to an existing surface to provide a bond with a superimposed course.

Tactile paving

Paving that has a change in surface condition that provides a tactile cue to alert pedestrians with vision impairments of a potentially hazardous situation.

Tangent point

Point at which a road ceases to be straight and curvature begins.

Taper

A section where the road width varies to vary the width of lane(s) or to reduce or increase the number of lanes. Tapers are typically provided at the starts and ends of auxiliary lanes.

Taxi (taxicab)

A vehicle that has a passenger carrying capacity similar to that of an automobile and that serves primarily as a demand-responsive public passenger vehicle for hire. It may be a converted automobile or one specially built for taxicab service.

Temporary traffic management

The physical measures and combination of traffic control devices used to guide road users through a work zone for the safety of the road users and the workforce.

QHDM GLOSSARY


Thematic road safety audit

A road safety audit that is more defined and focuses on single aspects of design provision or road user.

Three-leg intersection

An intersection with three legs, where two roads join.

Throughput

Traffic or volume of passengers or vehicles passing a point or series of points during a given period.

Time of concentration

The sum of the time of entry and the time of flow of surface water runoff directed to a stormwater drain.

T-intersection

A three-leg intersection in the general form of a “T.”

Topography

The physical features of the surface of the land including elevations, depressions, and rivers.

Topsoil

The uppermost layer of soil, usually 5 to 20 centimeters, that will normally contain organic matter, microorganisms, and a seedbank for the vegetation cover they support.

Tractor

A powered unit capable of propelling itself and towing unpowered units on a highway.

Traffic

The movement of vehicles or pedestrians through an area or along a defined route.

Traffic bollard

A device placed on a pedestrian refuge or traffic island to warn drivers of the obstruction. It may incorporate a traffic sign to indicate the direction of travel.

Traffic capacity

The maximum practicable traffic flow for given purposes or assumed for design purposes.

Traffic concentration

The number of vehicles per unit length of road at a specified time, excluding parked vehicles.

Traffic control

Regulation of traffic by traffic signals or traffic signs.

QHDM GLOSSARY


Traffic density

The traffic flow per unit of travelled way; usually expressed as the number of vehicles per hour per traffic lane.

Traffic flow

The number of vehicles, people, or animals passing a specific point within a specified time, in both directions unless otherwise stated.

Traffic island

A defined area between traffic lanes for control of vehicle movements or for a pedestrian refuge. Within an intersection, a median or an outer separation is considered a traffic island.

Traffic sign

A device mounted on a fixed or portable support whereby a specific message is conveyed by means of words or symbols, officially erected for the purpose of regulating, warning, or guiding traffic.

Traffic signal

Any power-operated traffic control device, other than a barricade warning light or steady burning electric lamp, by which traffic is warned or directed to take some specific action.

Traffic volume

The number of persons or vehicles passing a point on a lane, roadway, or other travel way during some time interval, often 1 hour, expressed in vehicles, bicycles, or persons per hour.

Trailer

A vehicle designed for carrying persons or property and drawn by a motor vehicle that carries no part of the weight and load of the trailer.

Transition

A section of barrier between two different barriers or, more commonly, where a roadside barrier is connected to a bridge railing or to a rigid object such as a bridge pier. The transition should produce a gradual stiffening of the approach rail so vehicular pocketing, snagging, or penetration at the connection can be avoided.

Transition curve

A curve in which the radius changes continuously along its length, connecting a straight length with a circular arc or two circular arcs of different radii or of opposite hand.

Transition length

The length of roadway required to distribute superelevation. This may be different from the length of a transition curve.

QHDM GLOSSARY


Transportation

Travel from one place to another of goods and people by public or private means.

Transverse

The horizontal direction normal to the longitudinal axis of a bridge.

Transverse distribution

The manner in which vehicular traffic is spread across the roadway.

Travelled way

The portion of the roadway for the movement of vehicles, exclusive of shoulders and bike lanes.

Treated sewage effluent

Effluent treated to a standard suitable for plant irrigation under controlled conditions that minimize or eliminate contact with humans.

Trenchless technology

Methods for utility and other line installation, rehabilitation, replacement, renovation, repair, inspection, location, and leak detection, with minimum excavation from the ground surface.

Trial pit

An excavation, usually by machine, occasionally by small tools and hand-dug, to inspect and record the soil and rock strata conditions or groundwater entry and to recover strata samples.

Trial trench pit

An elongated excavation, usually made by machine, to inspect and record the soil and rock strata conditions or groundwater entry and to recover strata samples.

Truck

A wheeled highway freight vehicle. Also referred to as a “goods vehicle”.

Truck apron

The optional outer, mountable portion of the central island of a roundabout between the raised, nontraversable area of the central island and the circulating roadway.

Trunk sewer

A sewer that receives flow from many tributary sewers and serves a large area.

Tunnel

A horizontal or near horizontal opening in soil excavated to a predesigned geometry by tunneling methods exclusive of cut-and-cover methods.

Turning traffic

Vehicles turning left or right at an at-grade intersection.

QHDM GLOSSARY


Two-lane roundabout

A category of roundabout where the circulatory roadway is two lanes wide.

Underpass

A grade separation where the subject highway passes under an intersecting highway or railroad. Also referred to as “undercrossing”.

Upstream

The part of the roadway where traffic is flowing toward the section in question.

Urban area

An area that contains or is zoned to contain built land use development.

Urban design

The art of making places in villages, towns, and cities that involve the design of buildings, groups of buildings, spaces, landscapes, and the establishment of frameworks and processes which facilitate successful development.

Urban form

The physical layout and design of the urban area, including structure, gain, density, scale, massing, appearance, and landscape.

Urban traffic control (UTC)

A centrally located system that uses fixed time, predefined signal timing plans to coordinate traffic signal controlled intersections within a highway network.

Utility corridor

Defined area within a highway right-of-way for utilities.

U-turn

A turning maneuver carried out through 180 degrees, resulting in the vehicle proceeding on the same road but in the opposite direction.

Vadose zone

Unsaturated zone between the ground surface and the groundwater table.

Vehicle

1. An assembly of one or more units coupled for travel on a highway; vehicles include one powered unit and may include one or more unpowered full trailer or semitrailer units.

2. Every 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 operating in a mixed-use alignment, to which other traffic is not required to yield the right-of-way by law, is a vehicle

QHDM GLOSSARY


Vehicle-actuated traffic signals

Traffic signaling equipment in which the duration of the red and green signal lights and the duration of the signaling cycle vary in relation to the traffic flow into and through the controlled area, as actuated by a detector.

Vehicle classification

The identification, summarization, and reporting of traffic volume by vehicle or axle configuration.

Vernacular

The way in which ordinary buildings were built in a particular place, making use of local styles, techniques, and materials and responding to local economic and social conditions.

Vertical alignment

The direction and course of the center line of a roadway in profile.

Vertical curve

The curve on the longitudinal profile of a roadway.

View

That which is visible from a particular point.

Visibility envelope

The area within and outside of the roadway that is required for compliant design visibility.

Vista

An enclosed view, usually a long and narrow one.

Vortex

A circular pattern of air created by the movement of an airfoil through the atmosphere.

Vortex grit remover

Automatic grit removal from continuous wastewater or intermittent stormwater flows in a low footprint, shop-fabricated installation.

Wadi

An Arabic term traditionally referring to a valley; in some cases, it normally refers to a dry riverbed that contains water only during times of heavy rain.

Walkway

A facility provided for pedestrian movement and segregated from vehicular traffic by a curb, or provided for on a separate right-of-way.

QHDM GLOSSARY


Wayfinding

The process by which people orientate themselves in space and navigate their way from place to place.

Way leave

A right-of-way granted by a landowner, typically to undertake construction or maintenance work on private land.

Wearing course

The top layer of a pavement that resists skidding, traffic abrasion, and the disintegrating effects of climate. Also referred to as “surface course”.

Weigh in motion (WIM)

A set of sensors and supporting instruments that measures the presence of a moving vehicle and the related dynamic tire forces at specified locations with respect to time; estimates tire loads, speed, axle spacing, vehicle class according to axle arrangement and other parameters concerning the vehicle; and processes, displays, and stores this information.

Work zone

The area of road construction, maintenance, or utility work and any additional areas of road required for advance warning signs, tapers, safety barriers, delineators, safety zones, buffers, and any other function associated with the road project, including alternative diversion routes.

Work zone road safety audit

A structured audit carried out at specified stages in the process defined in Qatar Work Zone Traffic Management Guide; specifically examines the elements of temporary traffic management to confirm compliance with the practices defined in that guide.

Worst credible parameters

Engineering parameters that reflect the most unfavorable conditions that the geotechnical practitioner realistically believes might occur.

Y-intersection

A three-leg intersection in the general form of a “Y.”

Yield line

A broken transverse traffic line across a traffic lane at the mouth of the minor road at a road intersection signifying that vehicles emerging from the minor road should yield to vehicles on the major road or roundabout.

Zoning

The division of an area into districts and the public regulation of the character and intensity of use of the land and improvements thereon.

Documents

Glossary - mme.gov.qa