1、American Association of State Highway and Transportation Officials AASHTO Transportation Glossary 4 thEdition2009 highway air rail water transit Transportation Glossary 2009 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of
2、applicable law. AASHTO The Voice of Transportation Copyright 2009, by the American Association of State Highway and Transportation Officials. All Rights Reserved. Printed in the United States of America. This book, or parts thereof, may not be reproduced in any form without written permission of the
3、 publishers. 2009 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. Transportation Glossary Executive Committee 20082009 Voting Members Officers:President: Allen Biehler, PennsylvaniaVice President: Larry L.
4、“Butch” Brown, Sr., MississippiSecretary-Treasurer: Carlos Braceras, Utah Regional Representatives:REGION I: Carolann Wicks, Delaware, One-Year TermJoseph Marie, Connecticut, Two-Year TermREGION II: Larry L. “Butch” Brown, Mississippi, One-Year TermDan Flowers, Arkansas, Two-Year TermREGION III: Kir
5、k T. Steudle, Michigan, One-Year TermNancy J. Richardson, Iowa, Two-Year TermREGION IV: Rhonda G. Faught, New Mexico, One-Year TermWill Kempton, California, Two-Year Term Nonvoting Members Immediate Past President: Pete K. Rahn, Missouri AASHTO Executive Director: John Horsley, Washington, DC 2009 b
6、y the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. v AASHTO The Voice of Transportation Preface The 2009 AASHTO Transportation Glossary is an update and revision of the 1983 Transportation Glossary and the 1998
7、 Transportation Glossary, which was unpublished. The greatest number of additions in terminology are related to bridge and drainage subjects. The new glossary also includes lists of organizational acronyms, abbreviations, and other glossary references. Terms and definitions in this glossary were tak
8、en from an unpublished 1998 AASHTO Glossary and supplemented with definitions listed in AASHTO publications issued after 1998. Several additional sources were also referenced, including the Highway Capacity Manual, Manual on Uniform Traffic Control Devices, Code of Federal RegulationsTitle 23, a Fed
9、eral Highway Administration (FHWA) list of roundabout terminology, and the Transportation Research Thesaurus. Glossary terms are listed in alphabetical order regardless of transportation mode. The glossary also includes two indexessubject area and keyword that provide cross references for the user.
10、2009 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. v Transportation Glossary Table of Contents Transportation Glossary . 1 Subject Area Index . 131 Keyword Index 155 Abbreviations, Symbols, and General Ac
11、ronyms 215 Common Engineering Abbreviations 221 References 227 Web Resources . 229 2009 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. Transportation Glossary A Abandonment The relinquishment of the public
12、 interest in right-of-way or activity thereon with no intention to reclaim or use again for highway purposes. Abrasion 1) Loss of section or coating of a culvert by the mechanical action of water conveying suspended bed load of sand, gravel, and cobble-size particles at high velocities with apprecia
13、ble turbulence. 2) Removal of stream bank material due to entrained sediment, ice, or debris rubbing against the bank. Absolute Block A block governed by the principle that no train shall enter the block while it is occupied by another train. Absolute Permissive On a track that is signaled in both d
14、irections, the section between sidings that, for opposing movements, extends from siding to siding and may be occupied by only one train and that, for following movements, is divided into two or more blocks that are signaled as absolute blocks. Absorption 1) The assimilation or taking up of water or
15、 other solutions by soil or other material, i.e., the entrance of water into the soil or rocks by all natural processes. It includes the infiltration of precipitation or snowmelt, gravity flow of streams into the valley alluvium, sinks, or other large openings, and the movement of atmospheric moistu
16、re. The process by which substances in gaseous, liquid, or solid form dissolve or mix with other substances. 2) The increase in mass of concrete resulting from the penetration of water into the concrete. Absorption Test A test made to determine the absorption of concrete. Abstraction That portion of
17、 rainfall that does not become runoff. It includes interception, infiltration, and storage in depressions. It is affected by land use, land treatment and condition, and antecedent soil moisture. Abstract of Title A document showing the condensed history of the title to property, containing portions
18、of all conveyances or other pertinent instruments relating to the estate or interest in the property, and all liens, charges, encumbrances, and releases. Abutment The earth-retaining structure that supports the superstructure at either end of a bridge. Considered part of the bridge substructure. “A”
19、 Car A motive-powered unit so designed that it may be used as the controlling unit of a multiple-unit train and that has adequate visibility in a forward direction, as well as a cab and equipment, to permit full control and observation of the propulsion power and brake applications for the train. Ac
20、celerate Stop Distance The distance required to accelerate an airplane to a specified speed and, assuming failure of the critical engine at the instant that speed (V) is attained, to bring the airplane to a stop. Transportation Glossary 2009 by the American Association of State Highway and Transport
21、ation Officials. All rights reserved. Duplication is a violation of applicable law. AASHTO The Voice of Transportation Acceptance Sampling and testing, or inspection, to determine the degree of compliance with contract requirements. Acceptance Constant (k) The minimum allowable quality index. Accept
22、ance Limit In variable acceptance plans, the limiting upper or lower value placed on a quality measure that will permit acceptance of a lot. (Unlike specification limits placed on a quality characteristic, an acceptance limit is placed on a quality measure. For example, in Percent Within Limits (PWL
23、) acceptance plans, PWL refers to specification limits placed on the quality characteristic, and the minimum allowable PWL identifies the acceptance limit for the PWL quality measure). Acceptance Number In attribute acceptance plans, the maximum number of defective or nonconforming units in the samp
24、le that will permit acceptance of the inspected lot or batch. Acceptance Plan An acceptable method of taking samples and making measurements or observations on these samples for the purpose of evaluating the acceptability of a lot of material or construction. Acceptance Sampling and Testing Sampling
25、, testing, and the assessment of test results done to determine whether or not the quality of produced material or construction is acceptable in terms of the specifications. Access Permission, liberty, or ability to enter, approach, or to make use of. Accessibility 1) A measure of mobility. 2) Total
26、 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. Accessible A site, building, facility, or portion thereof that can be approached, entered, and used by the physically impaired. A
27、ccessible Pedestrian Signal (APS) A device that communicates information about pedestrian signal timing in a nonvisual format including audible tones, verbal messages, and/or vibrotactile information. Access Point An intersection, driveway, or opening providing access to a roadway. Access Time The t
28、ime elapsed on a trip from the moment of leaving the point of origin to the moment of boarding a vehicle. Accrual Method The accounting procedure that recognizes revenues and expenses when they occur regardless of when cash is received or paid. Accuracy 1) The closeness or degree of agreement (withi
29、n 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. Acquisition or Taking The process of obt
30、aining right-of-way. Active Earth Pressure Lateral pressure resulting from the retention of the earth by a structure or component that is tending to move away from the soil mass. Act of God In law, a direct, sudden, or irresistible action of natural forces that could not reasonably have been foresee
31、n and prevented. Earthquake, tidal wave, tornado, hurricane, or any other cataclysmic phenomenon of nature beyond the contractors control that causes loss, damage, or injury to the work. Actual Cost Contractors actual cost to provide labor, material, equipment owned or invoiced rental, and administr
32、ative overhead necessary for the work. Addendum A contract revision developed between advertising and opening proposals. 2009 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. Transportation Glossary Additive
33、 A substance or agent added in small amounts to a basic ingredient of a mixture prior to mixing. Adjustment Factors Multiplicative factors that adjust a parameter for a base condition to represent a prevailing condition. Admixture 1) A material other than water, aggregates, and cement used as an ing
34、redient of concrete and added to the batch immediately before or during its mixture. 2) A substance or agent added in small amounts to the basic ingredients of a mixture during the mixing process. Adsorption The adhesion in an extremely thin layer of molecules (such as gases, solutions, or liquids)
35、to the surface of solid bodies or liquids with which they are in contact. Advanced Public Transportation Systems (APTS) Application of intelligent transportation systems technologies to the needs of public transit, including fixed- route systems as well as route deviation and demand-responsive modes
36、. Advanced Rural Transportation Systems (ARTS) A collection of intelligent transportation systems technologies applied to the rural environment. Advanced Traffic Management System (ATMS) Remotely operated traffic management system for monitoring and managing operations of a freeway system, including
37、 High-Occupancy Vehicles (HOV) lanes and arterial streets. Major elements of the system include surveillance, communications, and controls. Advanced Traveler Information Systems (ATIS) The dissemination of real-time traffic information to the traveling public over a variety of distribution channels.
38、 Advanced Vehicle Control and Safety Systems (A VCSS) Systems that focus on crash avoidance by enhancing driver performance. A VCSS include collision avoidance systems and automated highway systems. Advertisement A public announcement inviting bids for work to be performed or materials to be furnish
39、ed. Advisory Arbitration without a final and binding award. Aeroelastic Vibration Periodic, elastic response of a structure to wind. Aeronautical Information Publication A pilots operational manual containing information needed for the planning and conduct of flight in the National Airspace System (
40、conterminous U.S. only). Aesthetics The science or philosophy concerned with quality of visual experience, pertaining primarily to desirable visual values and with judgments concerning appealing design. Aesthetic Value The worth of an item of construction in terms of pleasing appearance or gratifyin
41、g performance. Afflux The backwater or height by which water levels are raised at a stated point, owing to the presence of a constriction or obstruction, such as a bridge. Agency 1) The State Highway or Transportation Department, Commission, or other organization, constituted under state or commonwe
42、alth laws, that administers highway or transportation work. 2) A responsible business or service authorized to act on behalf of others, i.e., a governmental department, consulting engineering firm, or owner of the facility or feature. Aggradation The general and progressive upbuilding of the longitu
43、dinal profile of a channel or within a drainage facility by the deposition of sediment. Agonic Line A line along which no magnetic variation occurs.A 2009 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. AAS
44、HTO The Voice of Transportation Aircraft Classification Number (ACN) A number expressing the relative effect of a large aircraft on a pavement for a standard subgrade category. Air Navigation Facility (NA V AID) Any facility used in, available for use in, or designed for use in aid of air navigation
45、, including landing areas; lights; any apparatus or equipment for disseminating weather information, for signaling, for radio direction finding, or for radio or other electronic communication; any other structure or mechanism having a similar purpose for guiding or controlling flight in the air or t
46、he landing or takeoff of aircraft. Airplane A power-driven fixed-wing aircraft, heavier than air, that is supported by the dynamic reaction of the air against its wings. Airport A defined area on land or water, including any buildings and installations, normally used for the takeoff and landing of a
47、ircraft. Airport Advisory Area The area within 10 statute miles (16 km) of an airport where a control tower is not operating but where a flight service station (FSS) is located. At such locations, the FSS provides advisory service to arriving and departing aircraft. Airport Advisory Service A servic
48、e provided by flight service stations at airports not served by a control tower. This service consists of providing information to landing and departing aircraft concerning wind direction and velocity, favored runway, altimeter setting, pertinent known traffic, pertinent known field conditions, airp
49、ort taxi routes and traffic patterns, and authorized instrument approach procedures. Airport Capacity The number of takeoffs and landings per hour that can be handled safely during good weather and during bad weather when radar is required to help air traffic controllers maintain safe separation between aircraft. Also referred to as Runway Capacity. Airport Layout Plan (ALP) Current and planned airport development portrayal, which may be part of an airport master plan. Airport Surveillance Radar (ASR) A relatively short-ra
