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Dictionary
H Point:
The mechanically hinged hip point of a manikin which simulates the actual pivot center of the human torso and thigh, described in Society of Automotive Engineers (SAE) Recommended Practice J826, "Manikins for Use in Defining Vehicle Seating Accommodations," November 1962.
(49CFR571)
Handling:
Physically moving cargo between point-of-rest and any place on the terminal facility, other than the end of ship's tackle.
(MARAD1)
Handoff:
A Controller action taken to transfer the radar identification of an aircraft from one Controller to another if the aircraft will enter the receiving Controller's airspace and radio communications with the aircraft will be transferred.
(FAA4) (FAA8)
Handy Line:
Small line used to throw between separated barges or boat and shore, (i.e., heaving line).
(TNDOT1)
Harmonized System of Codes:
An international goods classification system for describing cargo in international trade under a single commodity coding scheme. This code is a hierarchically structured product nomenclature containing approximately 5,000 headings and subheadings.
(MARAD2)
Have Numbers:
Used by pilots to inform Air Traffic Control (ATC) that they have received runway, wind, and altimeter information only.
(FAA4)
Hazard to Navigation:
For the purpose of 49CFR195, a pipeline where the top of the pipe is less than 12 inches below the seabed in water less than 15 feet deep, as measured from the mean low water.
(49CFR195)
Hazard Warning Signal:
Lamps that flash simultaneously to the front and rear, on both the right and left sides of a commercial motor vehicle, to indicate to an approaching driver the presence of a vehicular hazard.
(49CFR393)
Hazard Zone:
One of four levels of hazard (Hazard Zones A through D) assigned to gases, as specified in 49 CFR 173.116(a), and one of two levels of hazards (Hazard Zones A and B) assigned to liquids that are poisonous by inhalation, as specified in 49 CFR 173.133(a) of this subchapter. A hazard zone is based on the LC50 value for acute inhalation toxicity of gases and vapors, as specified in 49 CFR 173.133(a).
(49CFR171)
Hazardous Area Reporting Service:
Flight monitoring for Visual Flight Rules (VFR) aircraft crossing large bodies of water, swamps, and mountains. This service is provided for the purpose of expeditiously alerting Search and Rescue (SAR) facilities when required. Radio contacts are desired at least every 10 minutes. If contact is lost for more than 15 minutes, SAR will be alerted.
(FAA8)
Hazardous Goods:
The categories of hazardous goods carried by inland waterways are those defined by the European Provisions concerning the International Carriage of Dangerous Goods by Inland Waterways.
(TNDOT1)
Hazardous Inflight Weather Advisory Service (HIWAS):
Continuous recorded hazardous inflight weather forecasts broadcasted to airborne pilots over selected very high frequency omnidirectional (VOR) outlets defined as an HIWAS BROADCAST AREA.
(FAA4)
Hazardous Material (HAZMAT):
(See also Highly Volatile Liquid, Marine Pollutant) A substance or material which has been determined by the Secretary of Transportation to be capable of posing an unreasonable risk to health, safety, and property when transported in commerce, and which has been so designated. The term includes hazardous substances, hazardous wastes, marine pollutants, and elevated temperature materials as defined in this section, materials designated as hazardous under the provisions of 49 CFR 172.101 and 172.102, and materials that meet the defining criteria for hazard classes and divisions in 49 CFR 173.
(49CFR171) (49CFR390)
Hazardous Material (HAZMAT) Employee:
A person who is employed by a HAZMAT employer and who in the course of employment directly affects hazardous materials transportation safety. This term includes an owner-operator of a motor vehicle which transports hazardous materials in commerce. This term includes an individual, including a self-employed individual, employed by a HAZMAT employer who, during the course of employment: 1) Loads, unloads, or handles hazardous materials; 2) Tests, reconditions, repairs, modifies, marks, or otherwise represents containers, drums, or packagings as qualified for use in the transportation of hazardous materials; 3) Prepares hazardous materials for transportation; 4) Is responsible for safety of transporting hazardous materials; or 5) Operates a vehicle used to transport hazardous materials.
(49CFR171)
Hazardous Material (HAZMAT) Employer:
A person who uses one or more of its employees in connection with: transporting hazardous materials in commerce; causing hazardous materials to be transported or shipped in commerce; or representing, marking, certifying, selling, offering, reconditioning, testing, repairing, or modifying containers, drums, or packagings as qualified for use in the transportation of hazardous materials. This term includes an owner-operator of a motor vehicle which transports hazardous materials in commerce. This term also includes any department, agency, or instrumentality of the United States, a State, a political subdivision of a State, or an Indian tribe engaged in an activity described in the first sentence of this definition.
(49CFR171)
Hazardous Material Residue:
The hazardous material remaining in a packaging, including a tank car, after its contents have been unloaded to the maximum extent practicable and before the packaging is either refilled or cleaned of hazardous material and purged to remove any hazardous vapors.
(FRA2)
Hazardous Materials:
Any toxic substance, explosive, corrosive material, combustible material, poison, or radioactive material that poses a risk to the public's health, safety, or property when transported in commerce.
(FRA3)
Hazardous Substance:
A material, and its mixtures or solutions, that 1) Is identified in the appendix to 49 CFR 172.101; 2) Is in a quantity, in one package, which equals or exceeds the reportable quantity (RQ) listed in the Appendix A to 49 CFR 172.101; and 3) When in a mixture or solution which, for radionuclides, conforms to paragraph 6 of Appendix A, or, for other than radionuclides, is in a concentration by weight which equals or exceeds the concentration corresponding to the RQ of the material, as shown in the Table appearing in 49 CFR 171.8. This definition does not apply to petroleum products that are lubricants or fuels.
(49CFR171)
Hazardous Substance:
A material, and its mixtures or solutions, that is identified in the appendix to 49 CFR 172.101, List of Hazardous Substances and Reportable Quantities, of this title when offered for transportation in one package, or in one transport vehicle if not packaged, and when the quantity of the material therein equals or exceeds the reportable quantity (RQ). This definition does not apply to petroleum products that are lubricants or fuels, or to mixtures or solutions of hazardous substances if in a concentration less than that shown in the table in 49 CFR 171.8 of this title, based on the RQ specified for the materials listed in the appendix to 49 CFR 172.101.
(49CFR390)
Hazardous Waste:
Any material that is subject to the hazardous waste manifest requirements of the Environmental Protection Agency (EPA) specified in 40 CFR 262 or would be subject to these requirements absent an interim authorization to a State under 40 CFR 123, subpart F.
(49CFR171) (49CFR390)
Head:
1) The product of the water's weight and a usable difference in elevation gives a measurement of the potential energy possessed by water. 2) Marine restroom facility.
(DOE5)
Head Impact Area:
All nonglazed surfaces of the interior of a vehicle that are statically contactable by a 6.5-inch diameter spherical head form of a measuring device having a pivot point to "top-of-head" dimension infinitely adjustable from 29 to 33 inches in accordance with the procedure explained in 49 CFR 390.5.
(49CFR571)
Head Log:
The heavily reinforced section at each end of the barges and at the bow of the towboat to take the pressure of pushing the entire tow.
(TNDOT1)
Head of Passes:
A point near the mouth of the Mississippi River where the three principal distributary passes diverge. It is the point from which river distances are measured.
(TNDOT1)
Head On Collision:
1) Refers to a collision where the front end of one vehicle collides with the front-end of another vehicle while the two vehicles are traveling in opposite directions. 2) A collision in which the trains or locomotives involved are traveling in opposite directions on the same track.
(FRA2) (NHTSA3)
Headache Rack:
Heavy bulkhead that extends over cab from trailers, usually made of pipe and used in steel hauling.
(ATA1)
Header Board:
Protective shield at front end of flat bottom trailer to prevent freight from shifting forward.
(ATA1)
Headwaters:
The upper part of a river system, denoting the upper basin and source streams of a river.
(DOI4)
Heater:
Any device or assembly of devices or appliances used to heat the interior of any motor vehicle. This includes a catalytic heater which must meet the requirements of 49 CFR 177.834(1) when flammable liquid or gas is transported.
(49CFR393)
Heavy Duty Truck:
Truck with a gross vehicle weight generally in excess of 19,500 pounds (class 6-8). Other minimum weights are used by various law or government agencies.
(ATA2)
Heavy Hauler Trailer:
A trailer with one or more of the following characteristics: 1) Its brake lines are designed to adapt to separation or extension of the vehicle frame; or 2) Its body consists only of a platform whose primary cargo carrying surface is not more than 40 inches above the ground in an unloaded condition, except that it may include sides that are designed to be easily removable and a permanent "front-end structure" as that term is used in 49 CFR 393.106.
(49CFR393)
Heavy Rail:
An electric railway with the capacity for a "heavy volume" of traffic and characterized by exclusive rights-of-way, multi-car trains, high speed and rapid acceleration, sophisticated signaling, and high platform loading.
(APTA1)
Heavy Rail:
High-speed, passenger rail cars operating singly or in trains of two or more cars on fixed rails in separate rights-of-way from which all other vehicular and foot traffic is excluded.
(FTA1)
Heavy Rail (Rapid Rail):
Transit service using rail cars powered by electricity which is usually drawn from a third rail and usually operated on exclusive rights-of-way. It generally uses longer trains and has longer spacing between stations than light rail.
(FTA2)
Heavy Rail Passenger Cars:
Rail cars with motive capability, driven by electric power taken from overhead lines or third rails, configured for passenger traffic and usually operated on exclusive right-of-way.
(FTA1)
Height Above Airport:
(See also Minimum Descent Altitude) The height of the Minimum Descent Altitude above the published airport elevation. This is published in conjunction with circling minimums.
(FAA4)
Height Above Landing (HAL):
The height above a designated helicopter landing area used for helicopter instrument approach procedures.
(FAA4)
Height Above Touchdown (HAT):
The height of the Decision Height or Minimum Descent Altitude above the highest runway elevation in the touchdown zone (first 3,000 feet of the runway). Height Above Touchdown (HAT) is published on instrument approach charts in conjunction with all straight in minimums.
(FAA4)
Height/Decision Altitude:
A specified altitude or height (A/H) in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. Note 1: Decision altitude is referenced to mean sea level and decision height is referenced to the threshold elevation. Note 2: The required visual reference means that section of the visual aids or of the approach area which should have been in view for sufficient time for the pilot to have made an assessment of the aircraft position and rate of change of position, in relation to the desired flight path.
(FAA4)
Helicopter:
A rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors.
(14CFR1)
Helicopter:
A rotary-wing aircraft which depends principally for its support and motion in the air upon the lift generated by one or more power-driven rotors, rotating on substantially vertical axes. A helicopter is a V/STOL.
(AIA1)
Helicopter:
A heavier than air aircraft supported in flight chiefly by the reactions of the air on one or more power driven rotors on substantially vertical axes.
(FAA4)
Helipad:
A small, designated area, usually with a prepared surface, on a heliport, airport, landing/takeoff area, apron/ramp, or movement area used for takeoff, landing, or parking of helicopters.
(FAA4)
Heliport:
(See also Aerodrome, Aircraft Facility, Airport) 1) An area of land, water, or structure used or intended to be used for the landing and takeoff of helicopters and includes its buildings and facilities if any. 2) An area, either at ground level or elevated on a structure, that is used for the landing and take-off of helicopters and includes some or all of the various facilities useful to helicopter operations such as: helicopter parking, hangar, waiting room, fueling, and maintenance equipment.
(AIA1) (FAA2) (FAA4)
Helistop:
A minimum facility heliport, either at ground level or elevated on a structure for the landing and takeoff of helicopters, but without such auxiliary facilities as: waiting room, hangar parking, etc.
(AIA1)
Hermetically Sealed:
Closed by fusion, gasketing, crimping, or equivalent means so that no gas or vapor can enter or escape.
(49CFR171)
Hertz:
The standard radio equivalent of frequency in cycles per second of an electromagnetic wave. Kilohertz (kHz) is a frequency of one thousand cycles per second. Megahertz (mHz) is a frequency of one million cycles per second.
(FAA4)
High Frequency Communications:
High radio frequencies (HF) between 3 and 30 mHz used for air-to-ground voice communication in overseas operations.
(FAA4)
High Occupancy Vehicle (HOV):
Vehicles that can carry two or more persons. Examples of high occupancy vehicles are a bus, vanpool, and carpool.
(APTA1)
High Occupancy Vehicle (HOV) Lane:
Exclusive road or traffic lane limited to buses, vanpools, carpools, and emergency vehicles.
(APTA1)
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.
(49CFR37)
High Speed Rail:
A rail transportation system with exclusive right-of-way which serves densely traveled corridors at speeds of 124 miles per hour and greater.
(APTA1)
High Speed Taxiway:
A long radius taxiway designed and provided with lighting or marking to define the path of aircraft, traveling at high speed (up to 60 knots), from the runway center to a point on the center of a taxiway. Also referred to as long radius exit or turn-off taxiway. The high speed taxiway is designed to expedite aircraft turning off the runway after landing, thus reducing runway occupancy time.
(FAA4)
High Type Road Surface:
High flexible, composite, rigid, etc. (Surface/Pavement Type Codes 61, 62, 71-76 and 80).
(FHWA2)
High Volume Area:
An area which an oil pipeline having a nominal outside diameter of 20 inches or more crosses a major river or other navigable waters, which, because of the velocity of the river flow and vessel traffic on the river, would require a more rapid response in case of a worst case discharge or substantial threat of such a discharge.
(49CFR194)
High Water Buoy:
Small unlighted buoy permanently secured to the end of dikes, lock walls, bear traps, and other river front structures such as mooring cells for the purpose of marking them during high water when they are submerged.
(TNDOT1)
High Water Station:
The location to which lights or buoys are moved when river is at or near flood stage, the purpose being 1) To guide navigation in the high water and 2) To locate the light in a position of security against loss.
(TNDOT1)
High-Mileage Households:
Households with estimated aggregate annual vehicle mileage that exceeds 12,500 miles.
(DOE4) (DOE5)
Highly Volatile Liquid:
(See also Hazardous Material) A hazardous liquid which will form a vapor cloud when released to the atmosphere and which has a vapor pressure exceeding 276 kPa (40 psia) at 37.8 C (100 F).
(49CFR195)
Highway:
See also Arterial, Expressway, Freeway, Freeways and Expressways, Interstate Highway (Freeway or Expressway), Interstate Highway System, Local Streets and Roads, Road.
Highway:
Is any road, street, parkway, or freeway/expressway that includes rights-of-way, bridges, railroad-highway crossings, tunnels, drainage structures, signs, guardrail, and protective structures in connection with highways. The highway further includes that portion of any interstate or international bridge or tunnel and the approaches thereto (23 U.S.C. 101a).
(FHWA2)