The following glossary of terms explains some of the terminology associated with transportation and its various departments. If you do not see a definition for a word, or if you would like further clarification on a word that is listed below, please feel free to contact the El Paso County Department of Transportation at: firstname.lastname@example.org
A support of an arch or bridge, etc., which may carry a horizontal force as well as weight.
A traffic lane used to increase speed before entering the main lane of traffic.
Gravel, sand, slag, crushed rock or similar inert materials which form a large part of concretes, asphalts or roads including macadam.
One of a number of specific proposals, alignments, options, design choices, etc. in a study.
American Association of State Highway Officials (AASHTO)
An association of state departments of transportation, the AASHTO advocates multimodal transportation by providing technical services, information, and policy advice to member departments, the U.S. Department of Transportation, and Congress. The AASHTO is influential in national transportation policy decision-making.
American Automobile Association
A nonprofit federation of 116 motor clubs providing travel, insurance, financial and auto-related services; publishes various reports on issues such as fuel prices, motoring and travel conditions, and automobile expenses.
Americans with Disabilities Act ( ADA)
The legislation defining the responsibilities of and requirements for transportation providers to make transportation accessible to individuals with disabilities.
Arterial highways serve major traffic movements or major traffic corridors. While they may provide access to abutting land, their primary function is to serve traffic moving through the area.
A road that, in the USA, usually runs north-south, the word street being reserved mainly for east-west directions. Both streets and avenues are numbered in a logical way from which the position of each number can be closely estimated.
Average Daily Traffic Volume (ADT)
Average Daily Traffic is defined as the total traffic volume during a given period (from 1 to 364 days) divided by the number of days in that period. Current ADT volumes can be determined by continuous traffic counts or periodic counts. Where only periodic traffic counts are taken, ADT volume can be established by applying correction factors such as for season or day of week. For roadways having traffic volumes in two directions, the ADT includes traffic in both directions unless specified otherwise.
Additional excavation required to make up an embankment (or railway, road or canal) where the original amount of cut was insufficient.
A backacter attached to the rear of a loader; small versions are used in tunneling, hung from a monorail or the shield. A backhoe can dig below its wheels economically, including short trenches. If the backhoe is on the machine center-line it is a “center-post backhoe,” others are “offset backhoes.”
In a road the surfacing layers other than the wearing course, but particularly in the California bearing ratio method of designing flexible pavements, a layer of chosen and compacted soil which is covered with a thin layer of asphalt.
Bicycle Path (Bike Path)
A bikeway physically separated from motorized vehicular traffic by an open space or barrier and either within the highway right-of-way or within an independent right-of-way.
In the USA a wide road which in cities is usually planted with shade trees, sometimes also on the central strip.
A culvert of rectangular or square cross-section.
Bridge Inspection Program (BIP)
A FHWA program that inventories and inspects the condition of all bridges in the Federal-Aid Highway system. An evaluation of each bridge's load-carrying capacity is performed to determine if any deficiencies exist, and if necessary, appropriate action such as warning signs, bridge closing, rehabilitation or replacement, is taken.
A tractor usually on crawler tracks, with a wide blade, the moldboard, mounted in front of it, at right angles to the tracks. The moldboard is adjustable in height, angle and tilt. It normally moves material by pushing.
A pipe, conduit or road for directing flow of traffic around, instead of through, another pipe, conduit or road.
(Computer-aided design and draughting) – A CAD unit can help engineers, architects or other designers to work quickly and efficiently. It usually includes two VDUs, a small and large (the graphics display terminal), as well as the microcomputer generally hidden in a “black box.”
The maximum number of vehicles that can reasonably be expected to pass over a lane or a roadway during a given time period under prevailing roadway and traffic conditions. Typically, the maximum expressway capacity for automobiles is 2,000 vehicles per lane per hour.
Capital Improvement Projects
Refers to higher-cost transportation improvements, typically involving major infrastructure construction such as adding travel lanes to existing roads and building new roadways, interchanges, or railroads.
Categorical Exclusion (CE)
An action that does not individually or cumulatively have a significant impact on the human environment. This Categorical Exclusion does not require an Environmental Assessment or an Environmental Impact Statement.
Central Business District (CBD)
The downtown retail trade and commercial area of a city or an area of very high land valuation, traffic flow, and concentration of retail business offices, theaters, hotels and services.
Citizens Advisory Committee
Representative stakeholders that meet regularly to discuss issues of common concern, such as transportation, and to advise sponsoring agency officials. These groups effectively interact between citizens and their government.
Clean Water Act (CWA)
Federal legislation enacted in 1972 to protect water quality in the United States.
Collector highways are those highways that link local highways to arterial highways.
In rural areas routes serving intra-county, rather than statewide, travel. In urban areas, streets providing direct access to neighborhoods as well as direct access to arterials.
The general, inclusive, long-range statement of the future development of a community. The plan is typically a map accompanied by description and supplemented by policy statements that direct future capital improvements in an area.
Concrete Spreader, asphalts
A road-building machine that may be part of a slipform or fixed-form paving train. It uniformly spreads concrete or asphalt poured into it or dumped in front of it. Apart from the roller, the mixer and the trucks, it is the main unit needed for rolled concrete.
Congestion Mitigation and Air Quality Improvement Program (CMAQ)
Federal money contained in TEA-21 for projects and activities that reduce congestion and improve air quality.
Partial access restriction that gives preference to through traffic. Also provides for connections to selected public routes and to certain other adjacent locations where vehicles can enter or leave a roadway safely without interfering with through traffic.
Land between two termini within which traffic, transit, land use, topography, environment, and other characteristics are evaluated for transportation purposes.
Cracking in Concrete
Cracking is always expected in reinforced concrete, since it has such a high shrinkage on hardening. Additional cracks will occur on the stretched side of a beam but reinforcement should be inserted sufficient in quantity and closeness to make the cracks invisible to the naked eye and very close together. If a contraction or expansion joint is inserted, this will also reduce cracking near it. Rusting reinforcement also causes cracks in concrete.
A covered channel up to about 4 m width or a large pipe for carrying a watercourse below ground level, usually under a road or railway. It is usually laid by cut and cover.
Trenching to excavate a tunnel and then relaying the earth over it. Originally in UK cities this was the only feasible method because tunneling under a house was allowed only if it was one's own.
A traffic lane used to reduce speed before turning onto a different roadway or business entrance.
Demand Responsive Transportation
Transportation services that are flexible in terms of schedule and locations, such as taxis.
Established state and national standards and procedures that guide the establishment of roadway layouts, alignments, geometry, and dimensions for specified types of roadways in certain defined conditions. The principal design criteria for roadways are traffic volume, design speed, the physical characteristics of vehicles, the classification of vehicles, and the percentage of various vehicle classification types that use the roadway.
In the USA a dedicated street or road, but in Britain an access to a private house.
(Hauler) – Like a dumper, dump trucks are usually four-wheeled and move earth or other bulk loads, but the driver sits in front and the machine may be very large and not used on public roads. A large dump truck carrying 250 tons of earth has a 3000 hp electrical generator supplying the electrical power to each of the separate motors on the six driving wheels.
A grader equipped with a disc or plough collector and a belt elevator at right angles to its direction of travel. It digs earth or loose materials and discharges it to a height. It is very suitable for excavating road or railway cuttings or wide trenches.
Activities that assist communities reach social, cultural, aesthetic and environmental goals as well as help harmonize the transportation system with the community. Enhancements are part of the mitigation for project impacts and can include bike and pedestrian trails, renovating streetscapes, and scenic beautification.
Environmental Assessment (EA)
A document prepared early in a planning process that evaluates the potential environmental consequences of a project or activity. An assessment includes the same topical areas as an Environmental Impact Statement (EIS), but only assesses the effects of a preferred action, and in less detail than an EIS. An EA results in a decision, based on an assessment of the degree of impact of an action, that an EIS is necessary, or that an action will have no significant effect and a Finding of No Significant Impact (FONSI) can be made.
Environmental Impact Statement (EIS)
An EIS is a full disclosure, detailed report which, pursuant to Section 102(2)C of the National Environmental Policy Act (NEPA), establishes the need for the proposed action, identifies alternatives with the potential to meet the identified need, analyzes the anticipated environmental consequences of identified alternatives, and discusses how adverse effects may be mitigated. An EIS is prepared in two stages: a draft statement which is made available to the public for review and a final statement which is revised on the basis of comments made on the draft statement.
A beginning inventory or summary assessment of environmental features in a study area, usually performed during systems planning or preliminary environmental activities. From this preliminary information, the environmental impacts of the study alternatives will be determined. This overview may sometimes be referred to as Environmental Screening.
Environmental Protection Agency (EPA)
The federal agency charged with developing and enforcing national environmental policies. The EPA oversees federal policy regarding air and water pollution, among other topics.
Federal Aid Project
An activity, study, survey, project, or other work related to transportation authorized in advance by the Federal Highway Administration, Federal Transit Administration, or other federal agency, and which is paid for either partially or fully by public funds.
Federal Highway Administration (FHWA)
A branch of the United States Department of Transportation that administers the Federal Aid Highway Program, providing financial assistance to states to construct and improve highways, urban and rural roads, and bridges. The FHWA also administers the Federal Lands Highway Program (FLHP) that provides access to and within national forests, national parks, Indian reservations and other public lands. The FHWA is headquartered in Washington, DC, with field offices across the country, including one in each state.
Federal Transit Administration (FTA)
A branch of the United States Department of Transportation that is the principal source of Federal financial assistance to America's communities for the planning, development, and improvement of public or mass transportation systems. FTA provides leadership, technical assistance, and financial resources for safe, technologically advanced public transportation to enhance mobility and accessibility, to improve the nation's communities and natural environment, and to strengthen the national economy. The FTA is headquartered in Washington, DC, with regional offices in Atlanta, Boston, Chicago, Dallas, Denver, Kansas City, New York, Philadelphia, San Francisco, and Seattle.
Finding of No Significant Impact (FONSI)
A statement indicating that a project was found to have no significant impacts on the quality of the human environment and for which an environmental statement will therefore not be prepared.
The lowest condition of access control on state highways that allows an unlimited number of private driveway connections, intersections at grade, field entrances, or other land service linkages that give vehicles or pedestrians access to the highways.
In the USA a road for fast through-traffic to which abutting owners have no automatic right of access.
Functional Roadway Classification
The organization of roadways into a hierarchy based on the character of service provided. Typical classifications include arterial, local, and collection roadways.
Geographic Information System (GIS)
A computer-based system that links the geographic location of map features to text information or databases.
Design that deals with the dimensions of a facility and the relationships of its features such as alignment, profile, grades, widths, sight distances, clearances, and slopes as distinguished from structural design which is concerned with thickness, composition of materials, and load-carrying capacity.
Grader, Motor Grader
A self-propelled machine usually now with three axles and an engine of up to 300 hp with a wide, hydraulically adjustable blade for cutting, and moving and spreading soil smoothly to the shape required. In modern machines the driver is able to sit. The grader is more efficient than the bulldozer in smoothing rough ground for road building but it also makes ditches or windrows, or backfills trenches.
Untreated or only slightly washed, rounded, natural building aggregate, larger than 5mm (for concrete 10mm).
An environmental impact category encompassing all types of permitted and unregulated materials, sites, and substances that require prudent handling and treatment to prevent harm or danger.
High-Occupancy Vehicle (HOV) Lane
A lane designated exclusively for vehicles carrying two or more persons, such as buses, carpools, and vans.
A building, structure, site, district, or object that is significant in American history, architecture, archaeology, engineering, and culture.
Positive or negative effects upon the natural or human environment resulting from transportation projects.
Indirect Effects (see Secondary Effects)
Effects that can be expected to result from a given action and that occur later in time or further removed in distance, yet are reasonably foreseeable in the future; for example, induced changes to land use patterns, population density, or growth rate.
Intelligent Transportation Systems (ITS)
Refers to the use of advanced technologies (such as traffic sensors and communications equipment) to improve transportation operations.
A mode is a particular form of transportation, such as automobile, transit, carpool, ship and bicycle. Intermodal refers to connections between modes.
Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA)
Federal legislation that mandated the way transportation decisions were to be made and funded. This landmark $155 billion federal legislation signed into law in December 1991, called for broad changes in transportation decision-making, and included major revisions to metropolitan and statewide planning processes. ISTEA emphasized diversity and balance of modes, as well as the preservation of existing systems over construction of new facilities. The law expired in September 1997, and was followed by TEA-21.
J K L
A relatively narrow way or track.
Level of Service
A rating system used by traffic engineers to determine a roadway's ability to provide adequate capacity for the volume of traffic (number of vehicles) using the road.
A highway that has access to it restricted to designated points such as interchanges.
A self-propelled, wheeled (occasionally tracked) machine that may steer on all four wheels or be front-wheel or rear-wheel steered. In front a loading bucket, four-in-one-bucket, pallet fork or even a bulldozer can be fitted. Usually the engine is behind the driver but some loaders have the engine in front and an air compressor built in behind the driver. An excavator can slew 360 ° without its tracks. Loaders cannot slew more than about 250 ° with their rear-end equipment and very little if at all with their front-end equipment. When using the backhoe, the weight of the machine should not be carried on the wheels but on the two stabilizers (out-riggers) and on the lowered loading bucket to give rock-steady stability. Tires in good condition on average ground need about 65% more weight on them to produce the same pull or push as crawlers.
Long-Range Transportation Plan
A document resulting from a regional or statewide process of collaboration and consensus on a region or state's transportation system. This document serves as the defining vision for the region's or state's transportation systems and services. In metropolitan areas, the plan indicates all of the transportation improvement scheduled for funding over the next 20 years.
Major Investment Study (MIS)
The MIS is an evaluation of the effectiveness (such as level of use and ability to meet the mobility needs of the public) and cost-effectiveness of alternative transportation investments in attaining local, state, and regional goals and objectives for the metropolitan or rural area. The study uses a cooperative process that leads to a decision on the design concept and fiscal scope of an investment(s). The recommended design concept(s) may result in additional development as a transportation project(s).
A strip of land between the two carriageways of a motorway, sometimes with shrubs or a crash barrier along its center line.
Metropolitan Planning Organization (MPO)
A planning group designated for each urban area with a population of 50,000 or more. Members include both private citizens and local government officials. An MPO addresses federal aid planning mandates by producing local area transportation plans or transportation improvement programs on an annual or biannual basis, or by employing other strategies that make existing systems more efficient.
Removing shavings from a surface by pushing it past a rotating toothed cutter.
A machine tool for milling invented by E. Whitney in 1818. It can be an extremely complicated machine used for making drills and gears as well as for cutting channels and making plane surfaces.
Specific design commitments made during the environmental evaluation and study process that serve to moderate or lessen impacts deriving from the proposed action. These measures may include planning and development commitments, environmental measures, right-of-way improvements, and agreements with resource or other agencies to effect construction or post construction action.
The proportion of trips made on the roadway versus other modes of travel such as the public transit system.
Facilities serving more than one transportation mode or a transportation network comprised of a variety of modes.
A transportation facility built to accommodate two or more types of transportation modes (e.g. bus/rail terminal).
Multiple Use/Joint Development
The use of transportation facilities and highway rights-of-way and corridor areas for purposes additional to and compatible with the designed movement of transportation conveyances (such as vehicles on the traveled way of a roadway). Examples include recreation and park areas, public art, scenic and wildlife resource enhancement, non-residential developments, and parking facilities.
National Environmental Policy Act (NEPA)
Established by Congress in 1969, NEPA requires that federal agencies consider environmental matters when considering carrying out federal actions. This could include the preparation of Environmental Assessments (EAs) or Environmental Impact Statement (EIS) for projects with the potential to result in significant effects on the environment.
National Historic Preservation Act (NHPA)
Established by Congress in 1966, the NHPA sets a national policy for the protection of historic and archeological sites and outlines responsibilities for federal and state governments to preserve the nation's history.
National Pollutant Discharge Elimination System (NPDES)
Part of the Clean Water Act that deals with point discharges such as those from wastewater treatment plants, factories and storm sewers.
No-Build Alternative (also known as “No-Action Alternative”)
Option of maintaining the status quo by not building transportation improvements. Usually results in eventual deterioration of existing transportation conditions. Serves as a baseline for comparison of “Build” Alternatives.
A survey conducted of the traffic using the study area roadway system to determine/document current traffic patterns.
Para transit Service
Transit service for individuals with disabilities who are unable to use the fixed route public transit system.
Park and Ride
A transportation option whereby commuters park their cars in designated lots and complete their trips using public transportation or joining other commuters in a high-occupancy vehicle (HOV) (e.g. buses, subways, and carpool/vanpool).
In the USA a freeway which passes through a park and is administered by a local authority, often a park authority. It is not open to commercial traffic.
The whole construction of a road or airstrip including stabilized soil and the surface, whether asphalt, concrete, wooden or stone blocks, etc. Rigid pavements are of reinforced concrete. A flexible pavement may be of any other material including lean concrete. The first part of a pavement is the sub grade (soil) it is built on, and then comes the sub-base if any, then the base and finally the wearing course.
Time when a highway carries its highest volume of traffic, usually the morning or evening “rush” period when commuters travel to and from work.
Early phases of technical studies undertaken to determine all relevant aspects of transportation location, to identify feasible route alternatives or design options, and to assess various cost and benefit parameters before advancing the project into more detailed final design development.
Land that has the best combination of physical and chemical characteristics for producing food, feed, fiber, forage, oil seed, and other agricultural crops with minimum inputs of fuel, fertilizer, pesticides, and labor and without intolerable soil erosion, as determined by the Secretary of Agriculture. It does not include land that is already committed to urban development or storage.
A concise narrative, prepared at the outset of a project or study or as part of a project needs study, defining the fundamental situation or circumstance to be solved. A problem statement will generally describe a particular situation in which an expected level of performance is not being achieved, and will list one or more important factors that cause or contribute to the unacceptable performance.
Productive Agricultural Land
Any land used for production, commercial purposes, crops, livestock, and livestock products, including the processing or retail marketing of such crops, livestock, or livestock products if more than 50 percent of such proposed merchandised products are produced by the farm operator.
A general term to refer to a series of activities carried out by planners, including data assessment, appraisal of identified planning needs, and consideration of available or anticipated fiscal resources to result in the drawing up, scheduling, and planning of a list of identified transportation improvements for a given period of time.
The phase a proposed project undergoes once it has been through the planning process. The project development phase is a more detailed analysis of a proposed project's social, economic, and environmental impacts and various project alternatives. What comes from the project development phase is a decision reached through negotiation among all affected parties, including the public. After a proposal has successfully passed the project development phase, it may move to preliminary engineering, design, and construction.
A formal event held prior to a decision that gathers community comments and positions from all interested parties for public record and input into decisions.
An announced meeting conducted by transportation officials designed to facilitate participation in the decision-making process and to assist the public in gaining an informed view of a proposed project at any level of the transportation project development process. Also, such a gathering may be referred to as a public information meeting.
A general concept that categorizes a process used in certain types of environmental or route location studies where multiple factors are compared in a systematic and comprehensive manner on the basis of sound judgment. Factors analyzed by using a qualitative analysis are such that they cannot be measured in monetary terms, have no apparent common denominators, and are not readily quantifiable.
The process used in certain economic, cost-benefit, engineering, or traffic studies where multiple factors, elements, and/or outcomes are evaluated and compared by the use of measurable data. Certain mathematical models, formulas, numerical indices, rankings, and value matrices may be used to assist with such a process.
Record of Decision (ROD)
A concise decision document for an environmental impact statement that states the decision (selected alternative or choice), other alternatives considered, and mitigation adopted for the selected alternative choice.
The group of federal and state agencies or commissions which have various regulatory, jurisdictional, and/or administrative responsibilities in a variety of subject areas that are part of the transportation project development process. These agencies and commissions are involved in participating in project meetings, reviewing and evaluating studies, commenting on documents, and granting certain approvals.
A covering to a soil or rock surface to protect it from scour. It does not withstand earth thrust. Common revetments include: asphalt, beaching, concrete slabs precast or cast in place, mattresses, maritime plants, pitching, reinforced grass and rip-rap.
Land, property, or interest therein acquired or devoted to transportation purposes, including construction, maintenance, operations, and protection of a facility.
Stones for revetment from 7 to 70 kg in weight. They protect the bed of a river or its banks from scour.
A concrete, stabilized soil, earth, hoggin, tarred or other surface for vehicles or animals to travel on.
A wearing course or base consisting of hard asphalt and coarse aggregate laid hot and rolled until it is nearly free of voids.
The main equipment for compaction of soils or roads. Rollers weigh from 500 kg upwards. Pneumatic-tired rollers improve the density in depth as well as on the surface. Sheepsfoot rollers can compact cohesive soils but the surface remains loose.
A snowplow with a rotating blade to shoot the snow off the road.
Water moving over the surface of the ground.
Roadway maintenance activities and smaller construction projects that correct conditions occurring on or alongside an existing highway. Typically involves minor widening, resurfacing, regarding roadsides, hazard or obstacle elimination, guardrail installation, and miscellaneous maintenance.
Bitumen, road tar or an emulsion of either, applied as a thin film to a road surface.
A general term to define impacts which are caused by a specific action and which take place later in time or further removed in distance but are still reasonably foreseeable. Secondary effects can be indeterminate, may not be easily recognized, and can be difficult to identify and evaluate
A small road parallel to a main road. It is used by traffic stopping at houses and shops so as to avoid obstruction to through traffic.
Single-Occupancy Vehicle (SOV)
A car with no passengers.
A rotary snowplow is a self-propelled vehicle with an air blast or a rotating blade that throws the snow aside.
State Department of Transportation (State DOT)
A statewide agency that is responsible for conducting transportation planning activities in non-metropolitan areas of the state, and assisting MPOs in transportation planning for the metropolitan areas. State DOTs are also responsible for developing, designing, and constructing most of the projects on major highways in most states.
The design or construction of an improvement that is funded entirely with state highway or bridge funds.
Statewide Transportation Improvement Program (STIP)
Prepared by the state DOTs, the STIP is a staged, multiyear listing of projects proposed for federal, state, and local funding encompassing the entire state. It is a compilation of the TIPs prepared for the metropolitan areas, as well as project information for the non-metropolitan areas of the state and for transportation between cities.
Water from rain, sleet, hail and snow.
A ribbon of land used for a public highway in a town. In the USA the term is often reserved for east-west highways.
Study (or Project) Limits
The physical end points of a proposed project or study, usually designated at geographic or municipal boundaries, at intersections, at roadway segments where cross sections change, or at the beginning or end of numbered state traffic routes.
Study (or Project) Need Statement
A statement of specific transportation problems and/or deficiencies that have resulted in the search for improvements. Study (or project) needs are typically based on technical information and analyses.
Study (or Project) Purpose
A broad statement of the overall intended objective to be achieved by a proposed transportation improvement.
A geographic area selected and defined at the outset of engineering or environmental evaluations, which is sufficiently adequate in size to address all pertinent project matters occurring within it.
Surface Transportation Program (STP)
A transportation-funding program within TEA-21. STP funds may be used for roadway construction and improvements, operational improvement, transportation systems, bicycle and pedestrian facilities, transit, ridesharing programs and facilities and transportation planning and studies.
A thin coat of bitumen, road tar or emulsion laid on a road to improve the adhesion of a course above it.
Traffic Analysis Zone (TAZ)
A subdivision of the project (or study) area for which demographic data are collected in order to estimate traffic volume. The arrival and departure pattern of the estimated traffic is also organized by TAZs.
Transit Center (or Transit Station)
A transfer facility serving transit buses and other modes, such as automobiles and pedestrians. In the context of this document, transit centers are either on-line or off-line facilities with respect to the High Occupancy Vehicle (HOV) lane.
Transportation Equity Act for the 21 st Century (TEA-21)
A law enacted in 1998, TEA-21 authorized federal funding for transportation investment for the time period spanning fiscal year 1998 to fiscal year 2003. Approximately $218 billion in funding was authorized, the largest amount in history, and is used for highway, transit, and other surface transportation programs.
Transportation Improvement Program (TIP)
A staged, multiyear (typically three to five years) listing of surface transportation projects proposed for federal, state, and local funding within a metropolitan area. MPOs are required to prepare a TIP as a short-range programming document to complement its long-range transportation plan. TIPs contain projects with committed funds over a multiyear period.
A collaborative process of examining demographic characteristics and travel patterns for a given area. This process shows how these characteristics will change over a given period of time, and evaluates alternatives for the transportation system of the area and the most expeditious use of local, state, and federal transportation funding. Long-range planning is typically done over a period of twenty years; short-range programming of specific projects usually covers a period of three to five years.
Travel Demand Management (TDM)
A strategy for reducing congestion and pollution by reducing vehicle volume through such techniques as ridesharing and carpooling.
United States Department of Transportation (USDOT)
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.
To provide a gradual change from one slope to another, a curve is inserted between two lengths of a road or railway at different slopes. At the foot of a hill the curve is concave upwards, and at a summit, convex upwards.
Those areas that are inundated or saturated by surface water or groundwater at a frequency or duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.
X Y Z
The division of a land area into districts and the public regulation of the character and intensity of use of the land and improvements thereon.