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Terms that are in use on this site.

There are 111 entries in this glossary.
All A B C D E F G H I L M O P R S T V W Z
Term Definition
CLEAR ZONE

The area adjacent to the street (measured from the edge of the travel lane) that is kept clear of major obstructions.

COG

Council of Governments - A group of local governments that voluntarily organizes and cooperates to create a more comprehensive, regional planning effort.

COLLECTOR

A two- to four-lane roadway providing mobility and access.  Collector streets can be found in residential neighborhoods, commercial and industrial areas, and central business districts.  Collectors usually have minimal access control, and the right-of-way is typically 80 feet.  Collectors are designed to move traffic from local roads to secondary arterials.

COLOR TEMPERATURE

A method used to characterize the spectral properties of a light source and specify the appropriate light source type in architectural design; light sources of the same color can vary in quality (CRI is used to describe light source quality); lower color temperatures are warmer (yellow/red) while high color temperatures are cooler (blue); the standard unit for color temperature is Kelvin, K (e.g. candlelight is 1500k, daylight at noon is 5500k).

CONTROLLED INTERSECTION

Intersection with a traffic light or other traffic control device.

CORRIDOR

Transportation pathway allowing movement between activity centers; a corridor may encompass single or multiple transportation routes and facilities, adjacent land uses, and the connecting street network.

COUNTDOWN CLOCK

Traffic signal feature notifying pedestrians of the time remaining to safely cross the intersection.

CRI

Color Rendering Index - A system used to describe the effect of a light source on the color/appearance of an object, compared to a reference source.  The index uses a scale from 0-100 and is used as a quality distinction.

CROSSWALK

Marked portion of the street designated for pedestrian crossing, either mid-block or at an intersection.  The most common markings are double parallel lines, ladder, and zebra stripes.

CURB EXTENSION

An extension of the sidewalk or curb line into the parking lane to reduce the effective street width. Also known as curb bulb-outs or neckdowns, curb extensions significantly improve pedestrian crossings by reducing the pedestrian crossing distance, visually and physically narrowing the roadway, improving the ability of pedestrians and motorists to see each other, and reducing the time that pedestrians are in the street.  Curb extensions are only appropriate where there is an on-street parking lane. Curb extensions should not extend more than 6 feet from the curb, and must not extend into travel lanes, bicycle lanes or shoulders. The turning needs of larger vehicles, such as school buses, need to be considered in curb extension design.

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