Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

Office of Planning, Environment, & Realty (HEP)
Planning · Environment · Real Estate

HEP Events Guidance Publications Glossary Awards Contacts

Planning Glossary

Glossary Listing

View All | # | | A | B | C | D | E | F | G | H | I | J | K | L | M | N O | P | Q | R | S | T | U | V | W | X | Y | Z

By:
Keyword Definition
Demand Responsive Vehicle (Transit) A nonfixed-route, nonfixed-schedule vehicle that operates in response to calls from passengers or their agents to the transit operator or dispatcher.
Domestic Freight (Water) All waterborne commercial movement between points in the United States, Puerto Rico, and the Virgin Islands, excluding traffic with the Panama Canal Zone. Cargo moved for the military in commercial vessels is reported as ordinary commercial cargo; military cargo moved in military vessels is omitted.
Domestic Operations (Air Carrier) All air carrier operations having destinations within the 50 United States, the District of Columbia, the Commonwealth of Puerto Rico, and the U.S. Virgin Islands.
Dedicated Funds Any funds raised specifically for transit purposes and which are dedicated at their source (e.g., sales taxes, gasoline taxes, and property taxes), rather than through an allocation from the pool of general funds. (FTA1)
Degree of (Critical) Hazard A situation in which collision avoidance was due to chance rather than an act on the part of the pilot. Less than 100 feet of aircraft separation would be considered critical. (FAA10)
Degree of (No Hazard) Hazard A situation in which direction and altitude would have made a midair collision improbable regardless of evasive action taken. (FAA10)
Degree of (Potential) Hazard An incident which would have resulted in a collision if no action had been taken by either pilot. Closest proximity of less than 500 feet would usually be required in this case. (FAA10)
Department of Transportation (DOT) Establishes the nation's overall transportation policy. Under its umbrella there are ten administrations whose jurisdictions include highway planning, development and construction; urban mass transit; railroads; aviation; and the safety of waterways, ports, highways, and oil and gas pipelines. The Department of Transportation (DOT) was established by act of October 15, 1966, as amended (49 U.S.C. 102 and 102 note), "to assure the coordinated, effective administration of the transportation programs of the Federal Government" and to develop "national transportation policies and programs conducive to the provision of fast, safe, efficient, and convenient transportation at the lowest cost consistent therewith." (OFR1)
Depreciation and Amortization All depreciation and amortization expenses applicable to owned or leased property and equipment including that categorized as flight equipment or ground property and equipment. (BTS4)
Deregulation Revisions or complete elimination of economic regulations controlling transportation. For example, the Motor Carrier Act of 1980 and the Staggers Act of 1980 revised the economic controls over motor carriers and railroads. (MARAD1)
Domestic Produced in the United States, including the Outer Continental Shelf (OCS). (DOE5)
Driver 1) A person who operates a motorized vehicle. If more than one person drives on a single trip, the person who drives the most miles is classified as the principal driver. 2) An occupant of a vehicle who is in physical control of a motor vehicle in transport or, for an out of-control vehicle, an occupant who was in control until control was lost. (FHWA3) (NHTSA3)
Driver's License A license issued by a State or other jurisdiction, to an individual which authorizes the individual to operate a motor vehicle on the highways. (49CFR383)
Driving Under the Influence (DUI) The driving or operating of any vehicle or common carrier while drunk or under the influence of liquor or narcotics. (FTA1)
Department of Energy (DOE) The Department of Energy's overarching mission is to advance the national , economic and energy security of the United States; to promote scientific and technological innovation in support of that mission; and to ensure the environmental cleanup of the national nuclear weapons complex. The Department has four strategic goals toward achieving the mission: Defense Strategic Goal: To protect our national security by applying advanced science and nuclear technology to the Nation's defense; Energy Strategic Goal: To protect our national and economic security by promoting a diverse supply and delivery of reliable, affordable, and environmentally sound energy; Science Strategic Goal: To protect our national and economic security by providing world-class scientific research capacity and advancing scientific knowledge; and Environment Strategic Goal: To protect the environment by providing a responsible resolution to the environmental legacy of the Cold War and by providing for the permanent disposal of the Nation's high-level radioactive waste.
Department of Health and Human Services (HHS) The Department of Health and Human Services is the United States government's principal agency for protecting the health of all Americans and providing essential human services, especially for those who are least able to help themselves.
Department of Housing and Urban Development (HUD) HUD's mission is to increase homeownership, support community development and increase access to affordable housing free from discrimination. To fulfill this mission, HUD will embrace high standards of ethics, management and accountability and forge new partnerships--particularly with faith-based and community organizations--that leverage resources and improve HUD's ability to be effective on the community level.
Donut Areas Geographic areas outside a metropolitan planning area boundary, but inside the boundary of a nonattainment or maintenance area that contains any part of a metropolitan area(s). These areas are not isolated rural nonattainment and maintenance areas.
Demand-Responsive Descriptive term for a service type, usually considered paratransit, in which a user can access transportation service that can be variably routed and timed to meet changing needs on an as-needed basis.
Dial-A-Ride Term for demand-responsive systems usually delivering door-to-door service to clients, who make request by telephone on an as-needed reservation or subscription basis.
Direct Service Tribes ITGs that receive services directly from the BIA.
Direct Funding Funds transferred directly from the Secretary of the Interior to the ITG upon request for programs contracted or compacted under P.L. 93-638 as amended.

View All | # | | A | B | C | D | E | F | G | H | I | J | K | L | M | N O | P | Q | R | S | T | U | V | W | X | Y | Z

Top of Page
Updated: 03/21/2012
HEP Home Planning Environment Real Estate
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000