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UA: Urbanized Area (TRB1)

UAV: Unmanned Aerial Vehicle (MTMC1)

UBOA: United Bus Owners of America (TRB1)

UCRS: Urban and Rural Commuter Service (MOCD)

UFC: Uniform Freight Classification (49CFR171) (MARAD2)

UFO: Unidentified Flying Object

UHF: Ultra High Frequency (FAA19) (FAA8)

UITP: International Union of Public Transport (TRB1)

ULB: Unlighted Buoy (USCG5)

ULCC: Ultralarge Crude Carrier (DOE7)

ULEV: Ultra Low Emissions Vehicle (VDOT)

Ullage: See Outage.

Ultra-Low Emission Vehicle: A lean fuel vehicle meeting the more stringent Ultra-low emission standards. (DOE6)

UMLER: Uniform Machine Language Equipment Register (RSPA1)

UMTA: Urban Mass Transportation Administration (Now Federal Transit Administration) (OFR1)

UMTRI: University of Michigan Transportation Research Institute (NHTSA4) (NHTSA5)

UMTRIS: Urban Mass Transportation Research Information Service (TRB1)

UN: United Nations (RSPA1)

Under Construction Road: Road construction has begun but is not completed. (DOI3)

Under Construction Runway: Construction has begun but is not completed. (DOI3)

Underneath the Point: Directly below and downstream from the point of land. (TNDOT1)

Underpass: The grade separation where part or all of one feature instance is directly above part or all of another feature instance. (DOI3)

Undredged Shipping Lane: Lane has not been dug out. (DOI3)

Unfinished Oil: Includes all oils requiring further processing, except those requiring only mechanical blending. In most cases, these are produced by partial refining or purchased in an unfinished state for conversion to finished products by further refining. (DOE5)

Union of Soviet Socialist Republic (U.S.S.R): Consisted of 15 constituent republics: Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgystan, Latvia, Lithuania, Moldava, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan. As a political entity, the U.S.S.R. ceased to exist as of December 31, 1991. (DOE3)

Unit Load: Packages loaded on a pallet, in a crate or any other way that enables them to be handled at one time as a unit. (MARAD2)

Unit Load Device: Any type of freight container, aircraft container, aircraft pallet with a net, or aircraft pallet with a net over an igloo. (49CFR171)

Unit Tow: An integrated tow consisting of bow, center, and stem sections. Found generally in the liquid cargo trade. (TNDOT1)

Unit Train: A train of a specified number of railcars, perhaps 100, which remain as a unit for a designated destination or until a change in routing is made. (MARAD2)

United States (U.S.) Flag Carrier (or American Flag Carrier): One of a class of air carriers holding a Certificate of Public Convenience and Necessity issued by the DOT, approved by the President, authorizing scheduled operations over specified routes between the United States (and/or its territories) and one or more foreign countries. (FAA2) (FAA14)

United States (U.S.) Territories: Include Samoa, Guam, the Northern Marianas, and the Virgin Islands. (FHWA2)

United States Air Carrier: A citizen of the United States who undertakes directly by lease, or other arrangement, to engage in air transportation. (14CFR1)

United States Coast Guard (USCG): Established by act of January 28, 1915 (14 U.S.C. 1), became a component of the Department of Transportation on April 1, 1967, pursuant to the Department of Transportation Act of October 15, 1966 (49 U.S.C. app. 1651 note). The Coast Guard is a branch of the Armed Forces of the United States at all times and is a service within the Department of Transportation except when operating as part of the Navy in time of war or when the President directs. The predecessor of the Coast Guard, the Revenue Marine was established in 1790 as a federal maritime law enforcement agency. Other responsibilities include: search and rescue, maritime law enforcement, marine inspection, marine licensing, Great Lakes pilotage, marine environmental response, port safety and security, waterways management, aids to navigation, bridge administration, ice operations, deepwater ports, boating safety, Coast Guard auxiliary, military readiness, reserve training and Marine Safety Council. (OFR1)

United States Code: Contains a consolidation and codification of all general and permanent laws of the U.S. (USCG1)

United States Travel and Tourism Administration (USTTA): An agency in the Commerce Department; it's principal mission is to implement broad tourism policy initiatives for the development of international travel to the U.S. as a stimulus for economic stability. (USTTA1)

Unladen Inland Waterways Traffic: Any movement of an Inland Waterways Transport (IWT) freight vessel for which the gross weight of goods carried, including that of equipment such as containers, swap-bodies and pallets, is nil; as well as any movement of an IWT passenger vessel without passengers. (TNDOT1)

Unlatch: Release lock on fifth wheel to drop trailer. (ATA1)

Unleaded Gasoline: (See also Gasoline) Contains not more than 0.05 gram of lead per gallon and not more than 0.005 gram of phosphorus per gallon. Premium, regular and intermediate grades are included, depending on the octane rating. (DOE4) (DOE5)

Unlinked Passenger Trips: The number of passengers who board public transportation vehicles. A passenger is counted each time he/she boards a vehicle even though he/she may be on the same journey from origin to destination. (APTA1) (FTA1)

Unloaded Vehicle Weight: The weight of a vehicle with maximum capacity of all fluids necessary for operation of the vehicle, but without cargo, occupants, or accessories that are ordinarily removed from the vehicle when they are not in use. (49CFR571)

Unpaved Road Surface: Gravel/soil and unimproved roads and streets (Surface/Pavement Type Codes 20, 30 and 40). (FHWA2)

Unsatisfactory Condition Classification: Facility is not operational and is not serving the purpose for which it was constructed. (DOI2)

Unscheduled Repair: Maintenance requiring the emergency repair of a piece of equipment as distinguished from those repairs performed during a scheduled cycle. (GSA2)

Up the Hill: Anything away from the towboat and on shore. When a river man has "gone up the hill," he has gone ashore, whether it be in a city or on a mountainside or across a prairie. (TNDOT1)

Up-and-Down Rod: [with respect to rail operations] A rod used for connecting the semaphore arm to the operating mechanism of a signal. (49CFR236)

Upper Coupler Assembly: A structure consisting of an upper coupler plate, king-pin and supporting framework which interfaces with and couples to a fifth wheel. (49CFR393)

Upper Coupler Plate: A plate structure through which the king-pin neck and collar extend. The bottom surface of the plate contacts the fifth wheel when coupled. (49CFR393)

Upper Gage: A water level gage located at the upper end of the lock. (TNDOT1)

Upper-Half of Saddle-Mount: (See also King-Pin Saddle-Mount, Lower-Half of Saddle-Mount, Saddle-Mount) That part of the device which is securely attached to the towed vehicle and maintains a fixed position relative thereto, but does not include the "king-pin." (49CFR393)

UPS: Uninterruptible Power System (FAA19)

Urban: Usually refers to areas with population of 5,000 or greater. (DOE6)

Urban Area: Any area that includes a municipality or other built up place which is appropriate, in the judgement of the Secretary of Transportation, for a public transportation system to serve commuters or others in the locality taking into consideration the local patterns and trends of urban growth. (FTA1)

Urban Arterial Routes: Those public roads that are functionally classified as a part of the urban principal arterial system or the urban minor arterial system as described in volume 20, appendix 12, Highway Planning Program Manual. (23CFR470)

Urban Collector Routes: Those public roads that are functionally classified as a part of the urban collector system as described in volume 20, appendix 12, Highway Planning Program Manual. (23CFR470)

Urban Ferryboat: A boat providing fixed-route service across a body of water with one or more terminals within an urbanized area, excluding international and urban park ferries. (APTA1)

Urban Highway: Any highway, road, or street within the boundaries of an urban area. An urban area is an area including and adjacent to a municipality or urban place with 5,000 or more population. The boundaries of urban areas are fixed by the states, subject to the approval of the Federal Highway Administration, for purposes of the Federal-Aid highway program. (FHWA5)

Urban Inland Waterways Transport: Transport carried out on inland waterways located within the boundaries of a built-up area. (TNDOT1)

Urban Place: A U.S. Bureau of Census-designated area consisting of incorporated political units or closely settled unincorporated areas outside an urbanized area. (APTA1)

Urbanized Area: 1) Areas with a population of 50,000 or more, at a minimum, encompass an entire urbanized area in a state, as designated by the U.S. Bureau of the Census. The Federal Highway Administration (FHWA) approved, adjusted urbanized area boundaries include the census defined urbanized areas plus transportation centers, shopping centers, major places of employment, satellite communities, and other major trip generators near the edge of the urbanized area, including those expected to be in place shortly. 2) An approximate classification of sample households as belonging to an urbanized area or not. Those classified as belong to an urbanized area were either in a central city of a Metropolitan Statistical Area (MSA), or in a MSA but outside the central city, and within a zip code area with a population density of at least 500 people per square mile in 1990. (FHWA2) (FHWA3)

Urbanized Area Formula Program Funds: Financial assistance from the Urbanized Area Formula Program (formerly Section 9). This program governs the distribution of the public transit capital and operating block grant appropriations by urbanized area. For this form, it is the Federal capital assistance granted to public transit agency providers to designated recipients on behalf of transit providers. (FTA1)

URCS: Uniform Railroad Cost System (BTS7)

URISA: Urban and Regional Information Systems Association (ENO1)

US: United States (AIA1) (BTS2) (FAA2)

USAF: U.S. Air Force (FAA19) (FAA13) (FAA14)

USATCFE: U.S. Army Transportation Center & Fort Eustis (MTMC1)

USATS: U.S. Air Traffic Service Corporation (FAA7)

USATSCH: (TRADOC) U.S. Army Transportation School, Ft Eustis, VA (MTMC1)

USC: U.S. Code (FHWA10)

USCG: U.S. Coast Guard (MARAD4) (OFR1)

USCGC: U.S. Coast Guard Cutter (MTMC1) (USCG5)

Used Vehicle: A vehicle with prior use. (49CFR37)

Useful Thermal Output: The thermal energy made available for use in any industrial or commercial process or used in any heating or cooling application, i.e., total thermal energy made available for processes and applications other than electrical generation. (DOE5)

User: The external individual or group that receive services from the National Airspace System (NAS) (e.g., Pilot, Air Carrier, General Aviation, Military, Law Enforcement Agencies, etc.). (FAA8)

User Charge: A fee charged to users for goods and services provided by the federal, state and local governments. User charges, either directly or indirectly, are paid on a periodic or occasional basis with license fees and excises. User charges are also paid at the time infrastructure services are consumed with the payment of fuel taxes and tolls. (BTS3)

User Charge: A charge or fee for use of an improved waterway. Possible types of charges include: fuel taxes, lockage fees, segment tolls, and licensing of floating equipment. (TNDOT1)

User-Preferred Trajectory: The route, altitude profile, speed, and times of departure and arrival that the user prefers. (FAA7)

USMC: U.S. Marine Corps (FAA14) (FAA13)

USN: U.S. Navy (FAA14) (FAA13)

USOA: Uniform System of Accounts (FTA3)

USPS: U.S. Postal Service (FHWA12)

USRA: U.S. Railway Association (OFR1)

USTRANSCOM: U.S. Transportation Command (MTMC1)

USTTA: U.S. Travel and Tourism Administration (BTS8) (USTTA1)

UTCS: Urban Traffic Control Systems (FHWA14)

Utility Aircraft: An aircraft designed for general purpose flying. (AIA1)

Utility Airport: An airport designed, constructed, and maintained to serve airplanes in Aircraft Approach Category A and B. (FAA12)

Utility Employee: A railroad employee assigned to and functioning as a temporary member of a train or yard crew whose primary function is to assist the train or yard crew in the assembly, disassembly or classification of rail cars, or operation of trains (subject to the conditions set forth in 49CFR218.22. (49CFR218)

UTMS: Urban Transportation Modeling System (TRB1)

UTPP: Urban Transportation Planning Package (FHWA13)

UTPS: Urban Transportation Planning System (TRB1)

UZA: Urbanized Area (APTA1) (FHWA12)

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