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Glossary of Terms

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A
Add/Drop Lane

(see auxiliary lane)

Alignment

Alignment is the street or highway corridor used for project elements. For example, the location of light rail tracks is referred to as the light rail alignment.

Alternative

For the purposes of the Columbia River Crossing project, an alternative is a specific set of multimodal bridge, transit and highway solutions. Example: Supplemental Bridge with Bus Rapid Transit is an alternative that was analyzed as part of the Draft Environmental Impact Statement (EIS) process. 

Arterial lanes

Roads serving major traffic movements (high-speed, high volume) for travel between major points. They are typically multilane, but not divided roadways. In urban areas, they carry much of the traffic circulating within the urban area.

Auxiliary lane

A dedicated lane between highway interchanges—from one on-ramp to the next off ramp—that provides motorists with more time and extra room to speed up, slow down or merge when entering or exiting a highway.

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Box girder

A structural bridge support beam that is a hollow box; its cross-section is a rectangle or square. For example, the I-205 Glen Jackson Bridge is a concrete box girder type.

Braided ramp
Braided ramps separate merging and diverging traffic by creating a bridge for traffic to cross over and others to cross under. This improves safety by eliminating lane-weaving.
Bridge Influence Area (BIA)
The five mile segment of I-5 stretching from State Route (SR) 500 in Vancouver to approximately Columbia Boulevard in Portland. This area is also called the project area.
Bus Rapid Transit (BRT)

A type of high capacity transit that uses large buses and stops less often for fast, frequent service. Buses stop at transit stations or platforms. Reliable travel times are ensured when buses operate in a lane dedicated to bus use. BRT vehicles also have the flexibility to travel in high-occupancy-vehicle lanes, expressways or on ordinary streets.

Bypass lane
Bypass lanes provide preferential treatment to priority users such as transit, commercial vehicles and high occupancy vehicles (HOVs) by allowing unimpeded travel through ramp meters, intersections and toll plazas. Bypass lanes serve as an important tool for Transportation Demand Management (TDM) by providing time saving incentives for priority users.
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Capacity
The maximum number of vehicles that a given section of roadway or traffic lane can accommodate in one direction in one hour.
Collector-distributor lane

A parallel roadway designed to remove weaving from the main line and to reduce the number of mainline entrances and exits.

Columbia River Datum (CRD)

The plane of reference from which river stage is measured on the Columbia River from the lower Columbia River up to Bonneville Dam, and on the Willamette River up to Willamette Falls. Equals 1.82 feet above Mean Sea Level (equivalent to NGVD) at Vancouver, Washington.

Congestion

A condition that occurs when the demand is greater than the transportation system’s capacity. Recurrent congestion is caused by constant excess volume compared to capacity. Nonrecurring congestion is caused by actions such as special events and/or traffic incidents. For highways, congestion is traffic moving at or slower than 30 miles-per-hour.

Construction staging area

A temporary area where vehicles, supplies and construction equipment are positioned for access to and use at a construction site.

Context Sensitive Solutions
A collaborative, interdisciplinary approach that involves all stakeholders to develop a transportation facility that fits its physical setting and preserves scenic, aesthetic, historic and environmental resources, while maintaining safety and mobility.
Corridor

Highway lanes associated right of way and the adjacent area that is visible from and extending along the highway. The distance the corridor extends from the highway could vary with different basic qualities.

Cost Estimate Validation Process (CEVP)

The project’s cost-risk estimating process that reviews and validates cost and schedule variables such as inflation, cost for materials or labor and the availability of funding in order to actively manage and avoid cost overruns. 

Couplet

A fixed method of routing two directions of travel on two adjacent, parallel streets, instead of placing both directions of travel on a single street.

Cut-through traffic

Traffic not originating in, or destined to, the immediate neighborhood.

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Deck truss

A truss bridge is a bridge composed of connected elements that are stressed from tension, compression or both in response to dynamic loads. The truss may carry its roadbed on top, in the middle or at the bottom of the truss. When the roadbed is atop the truss it is called a deck truss.

Design Bid Build

A project delivery method where design and construction elements of a project are contracted to separate entities or contractors.

Design Build

A project delivery system where the design and construction are contracted to a single entity or contractor.

Design option

Design options are potential minor variations in project design that are evaluated for their effects on project performance, environmental or community impacts, cost or other factors in order to select the most appropriate project design.

Direct access ramp

Direct access ramps allow buses, carpools and vanpools to directly access managed lanes (e.g., high occupancy vehicle lanes) in the center of the highway. Direct access ramps come down from above, or up from below, the mainline and usually merge into the HOV lane from inside the median. By enabling carpools, vanpools and buses to connect directly with HOV lanes, drivers of these vehicles avoid the need to weave across the general-purpose lanes. Direct access ramps can improve safety, reduce congestion, save time, and increase reliability for both HOVs and general-purpose traffic.

Draft Environmental Impact Statement

A Draft Environmental Impact Statement (EIS) is a summary of the expected impacts each project design, or “alternative,” is likely to have on the surrounding area. It includes a detailed description of the following: the alternatives; the existing conditions in the environment; expected impacts from each of the alternatives; options to avoid, minimize or mitigate the impacts; costs, financing and cost effectiveness; and description of agency coordination.

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Easement

The legal right to use property belonging to another person for a stated purpose. An easement may grant the right to use the property surface, the property subsurface for a given depth range or the airspace above the property surface for a given range of elevations.  For example, the right to access a piece of property that contains utilities either in the ground or above.

Environmental Impact Statement (EIS)

A document required by federal and state agencies under the National Environmental Policy Act (NEPA). An EIS is required for major projects or legislative proposals that may significantly affect the environment. A tool for decision making, an EIS describes the positive and negative effects of the undertaking and identifies alternative actions.

Environmental Justice (EJ)

Environmental Justice is defined by the U.S. Environmental Protection Agency (EPA) as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, culture, education, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies” (EPA website). Fair treatment means that no group of people, including racial, ethnic, or socioeconomic groups, should bear a disproportionate share of the negative environmental consequences resulting from industrial, municipal, and commercial operations or the execution of federal, state, local, and tribal environmental programs and policies. Meaningful involvement means that potentially affected community residents have an appropriate opportunity to participate in decisions about a proposed activity that will affect their environment and/or health, the public's contribution can influence the regulatory agency's decision, the concerns of all participants involved will be considered in the decision-making process, and the decision-makers seek out and facilitate the involvement of those potentially affected.

Express Bus service

Transit service designed to speed up longer trips in major metropolitan areas during busy peak commuting hours by traveling long distances without stopping. Examples include routes between suburban Park-and-Rides and the central business district that operate on freeways or express buses that operate as local service buses until a certain point and then operate non-stop to the central business district.

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Failing intersection
An intersection in which motorists sit through at least two cycles at traffic lights.
Federal Highway Administration (FHWA)
A branch of the US 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 including survey, design, and construction of forest highway system roads, parkways and park roads, Indian reservation roads, defense access roads, and other federal lands roads.
Federal Transit Administration (FTA)

The Federal Transit Administration (FTA) provides stewardship of combined formula and discretionary programs to support a variety of locally planned, constructed and operated public transportation systems throughout the United States. Transportation systems typically include buses, subways, light rail, commuter rail, streetcars, monorail, passenger ferry boats, inclined railways or people movers.

Final Environmental Impact Statement (FEIS)

The Final Environmental Impact Statement (FEIS) contains analyses of environmental and community effects and describes how a replacement bridge, light rail and other project elements will improve safety and relieve congestion on Interstate 5 between Portland and Vancouver.

Flyover ramp

A ramp that crosses over (above) another ramp or portion of highway.

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General Contractor/Construction Manager

A project delivery method that allows an owner to work with a construction manager during the design process. At 60 – 90 percent design completion, the owner and the construction manager negotiate a 'guaranteed maximum price' for the construction of the project based on the defined scope and schedule. If this price is acceptable to both parties, they execute a contract for construction services, and the construction manager becomes the general contractor.

General purpose lanes
Traffic lanes available to all auto users.
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High Capacity Transit (HCT)
High capacity transit is a mode of transportation that provides efficient and fast travel for large numbers of people.  Portland’s MAX light rail is HCT, as is San Francisco’s BART system.  “Bus Rapid Transit” is another form of HCT, where buses have their own roadway and, therefore can operate reliable, high-speed express service.
High Occupancy Toll (HOT)
A toll on single-occupant vehicles use lanes or entire roads that are designated for the use of high-occupancy vehicles (HOVs, also known as carpools). Tolls are collected either by staffed toll booths, automatic number plate recognition, or electronic toll collection systems. High occupancy tolls are a form of road pricing. Toll rates can be variable depending on the hour and the traffic demand during that period; the closer to the peak hour, the higher the price.
High-Occupancy Vehicle (HOV)
An automobile, van, pick-up truck, or bus that carries enough people to travel in an HOV lane. The major goal of an HOV or “carpool” lane is to improve the roadway efficiency by increasing the number of people it carries, while minimizing travel time.
Human environment

The natural and built environment and the relationship of people with that environment. The natural environment can be described as air, water and land. The built environment refers to physical and cultural structures created by humans. When an Environmental Impact Statement is prepared and economic or social and natural or physical environmental effects are interrelated, then the Environmental Impact Statement will discuss all of these effects on the human environment.

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Impact

Synonymous with effect. Includes ecological impacts (such as the effects on natural resources, and on the components, structures and functioning of affected ecosystems), aesthetic, historic, cultural, economic, social or health impacts, whether direct, indirect or cumulative. Effects may also include those results from actions that may have both beneficial and detrimental effects, even if on balance the agency believes the effect will be beneficial. 

Intelligent Transportation Systems (ITS)

Intelligent Transportation Systems vary in technologies applied, from basic management systems such as car navigation, traffic light control systems, container management systems, variable message signs or speed cameras; to monitoring applications such as security CCTV systems; and then to more advanced applications which integrate live data and feedback from a number of other sources, such as weather information and bridge de-icing systems. 

Interchange

A road junction that typically uses grade separation and one or more ramps to permit traffic to pass through the junction without directly crossing any other traffic stream.

Interchange Area Management Plan

A joint Oregon Department of Transportation and local government long-term land use and transportation plan designed to balance and manage transportation and land use decisions in areas planned for future use as a highway interchange.

Intermodal/multimodal
The use of different types of transportation modes to move freight shipments and people, i.e. ships, trains, buses and trucks.
Interstate

A system of expressways or highways that connect most major U.S. cities. 

Interstate Collaborative Environmental Process (InterCEP)

Established to coordinate and streamline the regulatory reviews and permitting functions of the participating agencies of the Columbia River Crossing project. Members include representatives from key federal and state agencies responsible for protecting the region's air, water, wildlife and cultural resources. This committee must formally concur on project decisions affecting their areas of concern at major project milestones. In addition, the committee provides advice and consultation regarding the NEPA process to the Project Development Team at formal concurrence and identified decision points. They will use a "streamlining" approach patterned after Washington's Signatory Agency Committee processes and Oregon's Collaborative Environmental and Transportation Agreement on Streamlining.

Interstate commerce
Trade, traffic or transportation in the United States that involves more than one state.
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Light Rail Transit (LRT)

A type of high capacity transit system that uses single or multi-car electric rail cars on tracks in either a shared roadway or an exclusive right of way. Trains stop at stations or platforms.  Portland’s MAX system is an example of light rail.

Liquefaction

A phenomenon associated with earthquakes in which sandy to silty, water-saturated soils behave like fluids. As seismic waves pass through saturated soil, the structure of the soil distorts, and spaces between soil particles collapse, causing ground failure.

Locally Preferred Alternative (LPA)
The alternative selected by local decision-makers as the preferred solution to the project's identified needs.
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Managed lane

Managed lanes are used to achieve a traffic operation objective, such as giving preference to priority users (buses, carpools, vanpools, or commercial vehicles), balancing competing needs and/or optimizing traffic flows. Examples include express lanes, reversible lanes, toll lanes and high occupancy vehicle (HOV) lanes.

Metropolitan Planning Organization (MPO)

An agency designated by a governor to administer federally required comprehensive transportation planning and programming for a metropolitan area. An MPO must be in place in any urbanized area with a population in excess of 50,000. Metro is the MPO for the Portland metropolitan area.  The Southwest Washington Regional Transportation Commission is the MPO for the Vancouver-Clark County metropolitan area. 

Metroscope

The Metroscope land use allocation model for the seven-county region maintained by Metro provides a basis for forecasting where market trends would tend to drive household and employment growth taking into account changing demographic and economic profiles, local zoning and investment decisions, changes over time in accessibility based upon implementing long range transportation plans and the market feasibility of different types of commercial and residential development. This framework provides a platform upon which to test several scenarios relating to the CRC project to better understand the potential for growth inducing effects.

Minimum Operable Segment (MOS)
The purpose of selecting the MOS is to identify a segment of the Locally Preferred Alternative that provides the most cost-effective solution with the greatest benefits for the project. The MOS must be able to function as a stand-alone project and not be dependent on any future segments being constructed.
Mitigation

Measures taken to reduce adverse effects on the environment or community. Mitigation may include: avoiding a specific impact altogether by not taking a certain action or parts of an action; minimizing impacts by limiting the degree or magnitude of the action and its implementation; rectifying the impact by repairing, rehabilitating, or restoring the affected environment; reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action; or compensating for the impact by replacing or providing substitute resources or environments. 

Mode

A means of transportation for people and goods. Automobile travel, rail, cycling and air are all modes of transportation. 

Multi-use path

A path that accommodates more than one mode of travel or type of use. For example, a path that accommodates both bicyclists and pedestrians.

Multimodal

A transportation system that provides for more than one mode of transportation. For example, the project’s Locally Preferred Alternative would provide for automobile, truck, light rail bicycle and pedestrian modes to cross the Columbia River.

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National Environmental Policy Act (NEPA)

NEPA requires federal agencies to integrate environmental values into their decision making processes by considering the environmental impacts of their proposed actions and reasonable alternatives to those actions. To meet this requirement, federal agencies prepare a detailed statement known as an Environmental Impact Statement (EIS). EPA reviews and comments on EISs prepared by other federal agencies, maintains a national filing system for all EIS documents, and assures that its own actions comply with NEPA. 

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Optimization
To find the best possible solution to a technical problem in which there are a number of competing or conflicting considerations. For example, to design highway improvements that best improve the safety, flow and capacity of I-5 in the Columbia River Crossing project area.
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Park and Ride lot
A parking facility where individuals transfer from their own vehicles to other modes of public transportation.
Peak period
The time during which the maximum amount of travel occurs. Generally, there is a morning and afternoon peak period.
Project area

See Bridge Influence Area (BIA)

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Ramp meter by-pass lane
Ramp meters are traffic signals that control the entry of vehicles from ramps onto freeways. The ramp meters control the frequency and spacing of merging vehicles to improve overall traffic flow. A ramp meter by-pass lane allows priority users (e.g. buses, carpools or freight) to avoid stopping.
Record of Decision (ROD)

A Record of Decision issued by the Federal Highway Administration (FHWA) signals formal approval of an Environmental Impact Statement (EIS) concerning a proposed highway project. The ROD authorizes the project to proceed with final design, property acquisition and construction.

Regional Transportation Planning Organization (RTPO)

Authorized by the State of Washington’s legislature in 1990 to coordinate transportation planning among jurisdictions and to develop regional transportation plans. The Southwest Washington Regional Transportation Commission is the RTPO for Clark County, Washington. 

Reverse commuting
Movement in a direction opposite the main flow of traffic, such as from the central city to a suburb during the morning peak period.
Right of Way (ROW)

There are multiple definitions of the term. For the Columbia River Crossing project, Right of Way refers to property owned by or acquired by public agencies solely required for placing the roadway, light rail track and supporting facilities. 

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Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU)
This authorizes federal spending for highways and transit projects through the year 2010. Previous legislation of similar focus was known as “TEA-21” and “ISTEA”.  SAFETEA-LU will allocate $286.4 billion nation-wide over six years.
Seismic
Pertaining to, characteristic of, or produced by earthquakes or earth vibrations.
Single Point Urban Interchange (SPUI)
A single-point urban interchange (also known as an “X” interchange or urban diamond interchange) is a variant on the standard diamond shaped structure, whereby all traffic meets at one single traffic signal in the center of the bridge over the highway (or underneath the highway). These interchanges can accommodate more traffic in smaller spaces, hence their appeal in urban areas. The “SPUI” acronym often is pronounced spoo-ee.
Span
The distance between bridge piers, towers or abutments.
Stacked highway/transit bridge design

A bridge design that places highway traffic on one deck of the bridge and transit traffic on another deck of the bridge.

Stakeholder(s)

Individuals and/or organizations involved in or affected by a plan, program or project. Stakeholders may include elected officials (local, state, federal), public entities, non-profit organizations, community based organizations and professional/industry-related associations. 

Stormwater (runoff)
The portion of precipitation that does not naturally percolate into the ground or evaporate, but flows overland, in channels or in pipes into a defined surface water channel or a constructed stormwater facility.
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Terminus
The terminus level is the location along the alignment where the exclusive transit guideway would end. For example, the transit alternative terminus of the guideway is a site where a park-and-ride lot of a considerable size could be provided.
Transit

Transportation by a vehicle (bus, trolley, etc.) that provides regular or special transportation to the public, but not including school buses, charter or sightseeing services.

Transportation Demand Management (TDM)

An effort to reduce the number of people traveling by single occupancy vehicles (SOV) by promoting alternative non-SOV modes of transportation (carpools, vanpools, transit), time of travel (non-peak travel), work arrangements (telecommuting) and other tools. TDM efforts may also discourage the use of SOVs by imposing tolls or taxes. Often paired with Transportation Systems Management (TSM) tools. 

Transportation Systems Management (TSM)

The process of collecting traffic data, developing predictive models, regulating access, and providing timely motorist information on traffic conditions to optimize the safety and efficiency of the surface transportation system in a given area, usually a large urban area. Often paired with Transportation Demand Management (TDM) as a larger strategy.

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Value Engineering Study
A short formal project review, utilizing highly experienced experts in the project field, to try to identify and recommend alternative solutions that will add value to the project, by reducing costs or in other ways. The study follows a formal set procedure for identifying and evaluating areas of value savings, and usually takes place soon after a preferred design is identified and estimated. For large projects, this process is required by most funding sources.
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