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CAD |
(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.” |
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Capacity |
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. |
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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. |
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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. |
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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. |
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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. |
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Clean Water Act (CWA) |
Federal legislation enacted in 1972 to protect water quality in the United States. |
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Collector Highway |
Collector highways are those highways that link local highways to arterial highways. |
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Collectors |
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. |
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Comprehensive Plan |
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. |
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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. |
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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. |
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Controlled Access |
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. |
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Corridor |
Land between two termini within which traffic, transit, land use, topography, environment, and other characteristics are evaluated for transportation purposes. |
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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. |
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Culvert |
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. |
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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. |