Habitat is that location where a plant or animal lives. Also, habitat includes areas that are or may be occupied by a threatened or endangered species.
Environmental Manual
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A halftone is an analog image, usually a photograph, composed oSf small spots of varied size, giving the illusion of a continuous tone (for example, a newspaper photograph examined under a magnifying glass).
Communications Manual
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Handicapped refers to people who have physical or mental impairments that substantially limit one or more major life activities. In the context of transportation, the term usually refers to people for whom the use of conventional transit facilities would be impossible or would create a hardship. These people are also known as transportation handicapped or as people who have a public transportation disability.
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handling cylinders
Handling Cylinders are cylinders used to determine when the concrete strength is adequate to remove nonstressed concrete members from the casting forms.
700-I, Structural Test Procedures Manual
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hard coding
Hard coding is a method of eliminating the need for manually coding input data on source documents when the computer has permanently associated certain input data with specific accounting transactions.
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hash function
A hash is a function that maps keys to integers, usually to get an even distribution on a smaller set of values.
Information Security Manual
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Haul is the distance or route over which a load is transported.
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hazard elimination program
hazardous atmosphere Hazardous atmosphere is an atmosphere that may expose employees to the risk of death, incapacitation, impairment of ability to self-rescue (that is, escape unaided from a permit space), injury, or acute illness from one or more causes. The causes include flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit (LFL); airborne combustible dust at a concentration that meets or exceeds its LFL; atmospheric oxygen concentration below 19.5 percent or above 23.5 percent; atmospheric concentration of any substance for which a dose or a permissible exposure limit is published and, any other atmospheric condition that is immediately dangerous to life or health.
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hazardous materials
Hazardous materials are any solid, liquid, or gaseous material that, because of quantity, concentration or physical, chemical, or infectious characteristics, may (a) cause or significantly contribute to an increase in mortality or an increase in serious irreversible or incapacitating illness, or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of or otherwise managed.
Right of Way Collection
Anchor: #i1002012
hazardous waste
Hazardous waste, as defined in federal law, is a solid waste or combination of solid wastes that, because of quantity, concentration or physical, chemical or infectious characteristics, may: (a) cause or significantly contribute to an increase in mortality or an increase in serious irreversible or incapacitating illness; or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of or otherwise managed.
Environmental Manual
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hazardous waste operations
Hazardous waste operations is an emergency response activity.
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head (static)
Head (static) is the height of water above any plane or point of reference. The energy possessed by each unit of weight of a liquid, expressed as the vertical height through which a unit of weight would have to fall to release the average energy possessed. The standard unit of measure shall be the foot.
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header bank
The header bank is the embankment placed directly at the beginning or ending of a bridge structure.
Bridge Detailing Manual
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A headwall is the supporting structures at the ends of drainage structures.
Hydraulics Manual
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Headwater is that depth of flood water impounded upstream of a culvert due to the influence of the culvert restriction, friction, and configuration.
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heat or lot
Heat or lot is the amount of material produced during a certain period of time determined by the producer.
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heat sink
Heat sink is a solid or liquid placed in the microwave oven to absorb energy after the moisture has been driven from a test specimen. The heat sink reduces the possibility of over-heating the specimen.
Manual of Testing Procedures
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height of cover
The height of cover is the distance from crown of a culvert or conduit to the finished road surface or the base of rail.
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hierarchy of Texas highways
The hierarchy of Texas highways is: Interstate, US, SH, State Loops or Spurs, FM/RM, County Roads (CR), and Business Routes (BR).
Bridge Inspection Manual
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highly-available, highly-reliable
Terms which define a condition in which a technological architecture has been constructed with redundant (or backup) systems, components and/or communication pathways such that it is highly resistant to failure.
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High Mast Illumination Details
Contained in the Traffic Operations Standard Plans.
Highway Illumination Manual
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high mast lighting
High mast lighting is lighting fixtures mounted at heights of 100 feet or more.
Highway Illumination Manual
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high occupancy toll
A fee charged to vehicles using an HOV facility and carrying fewer than the required number of occupants.
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high occupancy/toll lane
HOT lane
High occupancy/toll (HOT) lanes serve both HOV users and those willing to pay a toll to use the restricted lane (typically during hours of peak demand).
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high occupancy vehicle
A vehicle having more than one occupant. Examples include carpools, vanpools, buses, and mini-buses. Transportation systems may encourage HOV use by having designated HOV lanes and designating a minimum number of occupants required to use these lanes.
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high occupancy vehicle lane
HOV lane
High occupancy vehicle (HOV) lanes provide preferential treatment to carpools, vanpools and buses carrying a minimum number of people in each vehicle. Dedicated lanes are restricted for this purpose, either on a part-time or full-time basis.
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high pressure sodium vapor lamp
High pressure sodium vapor lamps are electric light sources in which light is generated by an arc discharge in an atmosphere containing sodium mercury and xenon vapors.
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high risk area
A high risk area is a room or location that contains information resources used to support critical department functions that, if lost, would cause a work stoppage crucial to department operations. The central mainframe computer room is a high risk area.
Information Security Manual
Anchor: #i1008589
high speed rail
A rail service having the characteristics of intercity rail service which operates primarily on a dedicated guideway or track not used, for the most part, by freight, including, but not limited to, trains on welded rail, magnetically levitated (MAGLEV) vehicles on a special guideway, or other advanced technology vehicles, designed to travel at speeds in excess of those possible on other types of railroads. High Speed Rail has exclusive right of way and serves densely traveled corridors at speeds of 90 miles per hour and greater. High speed rail corridors/tracks may be shared with freight trains.
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Highway is the entire width between the boundary lines of every way publicly maintained when any part thereof is open to the use of the public for purposes of vehicular travel.
Equipment Manual
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highway advisory radio
A highway advisory radio refers to dedicated frequencies carrying traffic information.
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Highway Bridge Program
The Highway Bridge Program is a federal-aid program. The program was once known as Highway Bridge Replacement and Rehabilitation Program (HBRRP).
Historic Bridge Manual
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highway class
Highway class is the rural/urban description of the lane characteristics.
Finance Division
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highway functional classification
The highway functional classification of routes according to use, such as arterial, collector, and local. This classification is for transportation planning and design purposes.
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highway cost index
The highway cost index is a measure of the effect of inflation on the highway dollar. Used until 1985 to determine the amount of transfer from the General Fund.
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highway maintenance and service equipment
Highway maintenance and service equipment includes both on-road and off-road equipment.
Equipment Manual
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highway overpass
A highway-overpass is a grade separation where the subject highway passes over intersecting highway.
Bridge Detailing Manual
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Highway Safety Plan
A highway safety plan documents top priority highway safety problems and the strategies to address them. The plan is submitted to and approved by the National Highway Traffic Safety Administration and the Federal Highway Administration for funding under the federal 402 program.
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highway structure
Highway structure is a general term to refer to various highway design features which are of particular concern to utility installations, i.e., bridges.
ROW Utility Manual
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highway system designation
Highway system designation is the description of highways, from point "A" to point "B," including highway system (i.e., FM, IH), highway number, direction, mileage, and counties affected.
Texas Reference Marker (TRM) System User's Manual
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Highway Trust Fund
The Highway Trust Fund is a federal account established by law to hold receipts collected by the government and earmarked for highway programs and a portion of the federal mass transit program. It is supported by the federal gasoline tax and other user taxes.
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highway underpass
A highway-underpass is a grade separation where the subject highway passes under an intersecting highway.
Bridge Detailing Manual
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highway voucher
A highway voucher is TxDOT’s voucher number.
Finance Division
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Historic is Native American and Euro-American archaeological sites in North America dating after A.D. 1492.
Environmental Manual
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Historic Bridge Team
A Historic Bridge Team is an interdisciplinary team organized by the Bridge Division project manager to handle historic bridge projects.
Historic Bridge Manual
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historic properties
Buildings, structures, objects, sites or districts with historical or archeological significance that are listed in, or eligible for listing in, the National Register of Historic Places.
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historic sign
A historic sign is a sign that is attached to and is a contributing feature of a historic building or structure.
Maintenance Collection
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historically underutilized business
  1. A historically underutilized business is a business that is formed for the purpose of making a profit and is at least 51 percent owned by one or more persons who are United States citizens and are recognized by the State of Texas as having been economically disadvantaged because of their identification as members of a qualifying group - Asian Pacific, black, Hispanic, native Americans or American women - and who actively participate in the control, operation, and management of the business in proportion to their ownership interest. Owners must be residents of Texas, and the business must have a permanent business office located in Texas.
  2. Purchasing Manual
  3. A historically underutilized business is any business so certified by the General Services Commission.
  4. Engineering Architectural and Surveying Services Manual
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home-based work trip
Home-based work trips are trips between a person’s home and place of employment for the purpose of working.
Traffic Data and Analysis Manual
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home-based non-work trip
Home-based non-work trips are trips between a person’s home and other destinations which are not for the purpose of working.
Traffic Data and Analysis Manual
Host-based is information, such as audit data from a single host, which may be used to detect intrusions.
Information Security Manual
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horizontal alignment
Horizontal alignment is the positioning of a roadway, as shown in the plan view, using a series of straight lines called tangents connected by circular curves.
Survey Manual
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horizontal curve
A horizontal curve is a simple, circular arc joining two straight lines known as tangents.
Survey Manual
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horizontal (eye) gaze nystagmus
The horizontal (eye) gaze nystagmus is an involuntary jerking of the eyes that occurs as a person moves his or her eyes to the side when under the influence of alcohol or certain other drugs. HGN is one of the indicators used in the Standardized Field Sobriety Test.
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horizontal entrance angle
Horizontal entrance angle is the angle, in a plane parallel to the base of the tile, between a line in the direction of the incident light and a line perpendicular to the leading edge of the reflective surface.
Departmental Material Specifications
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hot bins
Hot bins are aggregate bins that feed directly into the weight-box or the proportioning mechanism.
Manual of Testing Procedures
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hot mix
Hot mix applies to a paving mixture of asphalt cement and aggregate which have been combined while hot. It is also placed and compacted above 175º F. Temperature is a critical factor in the workability of the mix, as well as the durability of the finished pavement.
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hot soak emissions
Hot soak emissions are evaporated gasoline emissions occurring after the end of a vehicle trip due to the heating of the fuel, fuel lines and fuel vapors.
Traffic Data and Analysis Manual
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A household is an occupied dwelling unit in which occupants form a single economic unit regarding housing.
Traffic Data and Analysis Manual
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household income
  1. The household income is the median or average income earned by all persons living in a single household.
  2. Traffic Data and Analysis Manual
  3. The total gross income received for a 12-month period from all sources (earned and unearned) including, but not limited to wages, salary, child support, alimony, unemployment benefits, workers compensation, social security or the net income from a business. It does not include income received or earned by dependent children and full-time students under 18 years of age.
  4. Right of Way Manual
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household size
The household size is the number of persons living in one household. In travel demand modeling household size is generally referred to as 1, 2, 3, 4, or 5or more person households.
Traffic Data and Analysis Manual
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Houston automatic spooling program
The Houston automatic spooling program is a control system for submitting jobs to a large scale computer that allows the operators to control the flow of jobs through the system.
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Houston District
The Houston District is a TxDOT district office including the following counties: Brazoria, Fort Bend, Galveston, Harris, Montgomery, and Waller. Area offices are located in Brazoria; Fort Bend; Galveston; East, northeast, northwest, and south Harris County, Montgomery and Waller. The Houston district also operates the Galveston/Port Bolivar ferries and houses a Vehicle Titles and Registration Regional Office.
Inside TxDOT
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A hub is a place of convergence where data arrives from one or more directions and is forwarded out in one or more other directions. A hub usually includes a switch of some kind.
Information Security Manual
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HUB Subcontracting Plan
A Historically Underutilized Business (HUB) Subcontracting Plan is a requirement placed on vendors to encourage their utilization of historically underutilized businesses where subcontracting is practical. Applies to all delegated purchases with an estimated total cost of $100,000 or more where there are subcontracting opportunities for the procurement. [TGC §2161.181-182, 1 TAC §111.11]
Purchasing Manual
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human environment
Human environment means interpreted comprehensively to include the natural and physical environment and the relationship of people with that environment.
Environmental Manual
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Human Resources Division
The Human Resources Division manages employee services, oversees employee performance planning and evaluation, and administers the department’s recruitment and training program.
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Human Resources Management (former SMT)
Human Resources Management is one of TxDOT’s seven functional areas. The goal of the Human Resources Management is to provide comprehensive human resources services to all TxDOT employees, prospective employees and other users.
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Hydraulics is a branch of engineering dealing with liquids in motion.
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hydric soils
Hydric soils are wetland soils. These soils favor the production and regeneration of hydrophytic vegetation. A hydric soil is either saturated with water and virtually free of oxygen at or near the surface during significant periods of the growing season or the soil is flooded for significant periods when the soil temperature is above 5 degrees centigrade. Field indicators may include gray color or mottling with chrome, manganese or iron concentrations, an organic horizon, free water within the root zone and a sulfur odor in the soil.
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hydrogen ion
Hydrogen ion refers to acidity or alkalinity of water or soil. An ion is a charged atom or group of atoms in solution or in a gas. Solutions contain equivalent numbers of positive and negative ions.
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Hydrology is the study of the occurrence and distribution of the natural waters of the earth.
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hydrophytic vegetation
Hydrophytic vegetation refers to wetland plant species. Plants adapted for life within habitats that have permanent or alternating dry and inundated and/or saturated soil conditions.
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Hydroseeding is a method of broadcasting seed and sometimes lime, fertilizer, and mulch together in a mixture of water.
Hyperlinks are informational pathways that users of an online document can select to summon new topics, or more detailed information by clicking a mouse. Hyperlinks can unite different topics and show their relationships through the retrieval of information from an existing Web site or page, a specific file, or document.
Information Security Manual
Hypertext is usually a word or term that is linked to a definition, file or document.
Information Security Manual
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Hypertext Markup Language
Hypertext Markup Language is the language used to publish documents on the Word Wide Web portion of the Internet.
Information Security Manual
Anchor: #i1003230
Hypertext Transport Protocol
Hypertext Transport Protocol is an information-serving protocol used to transfer files on the World Wide Web. Graphics, text and sounds can be transmitted.
Information Security Manual
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