You need to upgrade your Flash Player
Download the most recent Flash plugin here.



The part of a suspension bridge or cable-stayed bridge that supports suspension support to the deck; the cable is made of many steel wires bound together into strands and anchored at each end.

cable barrier

A flexible type of traffic barrier consisting of multiple steel cables mounted on steel posts. See also "guardrail."

cable saddle
The cable saddles sit at the summit of each bridge tower. They hold the main suspension cable where it crosses over each tower leg. As traffic, wind and temperature changes affect the movement of the cables, the saddles absorb the load and shift it to the towers.
cable spinning
The technique of pulling wires from the bridge anchorage over towers and back to form the main cable; a "spinning wheel," or "traveler," carriers the wires; at the anchorage the strands of wire are attached to the eye-bar; the wires are grouped into strands then bound tightly together to form strong suspension cables.
cable-stayed bridge
A bridge in which the superstructure is directly supported by cables or stays, passing over or attached to a tower or towers located at the main pier(s).
"Caisson" is the French word for "box." A caisson is a huge box made of steel-reinforced and waterproof concrete with an open central core. At the base of the caisson is its "cutting edge" of plate steel. In a suspension bridge the caisson becomes the foundation, the pier, supporting for the bridge's towers.
The maximum number of vehicles (vehicle capacity) or passengers (person capacity) that can pass over a given section of roadway or transit line in one or both directions during a given period of time under prevailing roadway and traffic conditions.
capital costs
Expenses related to the purchase of tangible property, such as land, buildings and vehicles.
Anything other than passengers, carried for hire, including both mail and freight.
A shipment of not fewer than 5 tons of one commodity.
Formal name for a craft employee that inspects and repairs railway cars.
The movement of a car a distance of one mile; an empty car-mile is a mile run by a freight car without a load; a loaded car-mile is a mile run by a freight car with a load.
Two or more people sharing the use and cost of a privately owned vehicle in traveling to and from prearranged destinations; see also vanpool.
Concrete poured within form at project site to create a structural element in its final position.
Temporary foot bridges, used by bridge workers to spin the main cables (several feet above each catwalk), and attach the suspender cables that connect the main cables to the deck.
The separation or regulation of conflicting traffic movement into definite paths of travel by the use of pavement markings, raised islands or other subtle means, to facilitate the safe and orderly movement of both vehicles and pedestrians.
chevron signs
A chevron symbol (sideways "V") in black, against standard yellow background, on a vertical rectangle; used as an alternate or supplement to standard delineators and to large arrow signs.
A horizontal member of a truss.
Class 1
A railroad having operating revenues of more than $256 million annually.
Clean Air Act (CAA)
The original Clean Air Act was passed in 1963, but our national air pollution control program is actually based on the 1970 version of the law. The 1990 Clean Air Act amendments are the most far-reaching revisions of the 1970 law.
clear zone
Area adjacent to the roadway absent of obstructions or with protected elements.
closed-end street
A street that has only one egress to any other existing street or planned street identified in the local Transportation System Plan; cul-de-sacs, dead-end and looped streets are examples of closed-end streets.
cloverleaf interchange
A form of interchange that provides indirect right-turn movements in all four quadrants by means of loops; generally used where the turning and weaving volumes are relatively low; this type of interchange eliminates all crossing conflicts found in a diamond interchange, but requires more area; the cloverleaf type of interchange can have one or two points of entry and exit on each through roadway.
coal car
A freight car with fixed sides and no roof; for transporting coal.
cold-in-place (CIP) recycling
CIP recycling is an ecofriendly pavement rehabilitation process that uses 2 to 5 inches of the current road surface and pulverizes the material down to a specific aggregate size, and then reuses the material to pave that same road. The process is efficient in saving costs on labor and transportation.
collector/distributor streets
A street that gathers and disperses traffic between larger arterial highways and smaller streets; a collector/distributor street has intersections and provides access to abutting properties.
collector highway
Collector highways are those highways that link local highways to arterial highways.
In rural areas, routes serving intracounty, rather than statewide travel; in urban areas, streets providing direct access to neighborhoods, as well as direct access to arterial.
Commercial and Industrial Network (CIN)
Designated road system of primary highways that connect the state's regional growth areas and carry a significant amount of the state's commercial traffic; the CIN does not include the interstate system.
commercial motor vehicle
Any self-propelled or towed vehicle used on the public highways in commerce to transport passengers or cargo, if the vehicle has a gross weight of 10,000 pounds or more; or is designed to transport more than 15 passengers, including the driver, or is used to transport hazardous materials as defined by law.
commercial service airport
An airport receiving scheduled passenger service and having 2,500 or more enplaned passengers per year.
common carrier
Holds himself out for hire to the public; must post rates and cannot discriminate against customers whose cargo he is equipped to carry.
commuter lane
See high-occupancy vehicle lanes.
commuter rail
Local and regional passenger train operations between a central city, its suburbs and/or another central city; commuter rail usually has only one or two stations in the central business district; it is also known as "suburban rail."
commuter rail transit
Also called regional rail transit, the passenger railroad service carries passengers within urban areas or between urban areas and their suburbs. Commuter rail transit differs from rail rapid transit in a number of ways: heavier passenger cars, longer average trip lengths and passenger stations spaced farther apart.
complete interchange lighting (CIL)
Includes lighting in the interchange area on both the acceleration and deceleration areas, plus the ramps through the terminus.
composite photometry
Light measurement applied to a high-mast lighting system that employs a counter beam arrangement, to take advantage of the efficiency with which pavement luminance can be increased with light directed upstream, while enhancing positive contrast through additively of vehicle headlighting with the light directed downstream.
compressed work week
Also called alternative work hours; alternatives to the Monday through Friday, 8 a.m. to 5 p.m. work schedule; a compressed work week allows employees to work longer days and report to the work site less often.
concrete safety shaped barrier (CSSB)
Commonly used median barrier where there is heavy vehicle travel and narrow medians.
Highway congestion results when traffic demand approaches or exceeds the available capacity of the transportation facility(ies).
Congestion Mitigation and Air Quality improvement program (CMAQ)
This federal funding source supports programs and projects to improve air quality.
connecting carrier
Railroad with a physical connection to another.
constant warning time (CWT)
Circuitry at active warning devices that provides a constant warning time, despite the speed at which a train is approaching.
A detailed review of construction issues and sequencing of a project during the project development phase.
continuously operating reference station (CORS)
Surveyors, geographical information system users, engineers, scientists and the public that collect GPS data can use CORS data to improve the precision of their positions.
contract authority
A federal budgetary term that refers to a form of budget authority permitting obligations to be incurred in advance of appropriations; advance obligations, however, have been limited by the appropriations committees with obligation limitations.
See luminance contrast.
contrast sensitivity
Ability to perceive a lightness or brightness difference between two areas; frequently measured for a range of target patterns differing in value along some dimension, such as pattern element size and portrayed graphically in a contrast sensitivity function in which the reciprocal of contrast threshold is plotted against pattern spatial frequency or against visual angle subtended at the eye by pattern elements.
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.
A broad geographical band that follows the general directional flow or connects major sources and destinations or trips; generally representing the major travel patterns within a region, corridors may contain a number of streets, highways and transit route alignments.
County-State Traffic Engineering Program (C-STEP)
A traffic safety improvement program funded 45 percent by the county and 55 percent by the state on the rural portion of the primary road system.
crash rate
Measure of the number of crashes on a roadway segment related to the amount of traffic on that segment; the rate is calculated by taking the number of crashes over a given time period divided by the total vehicle-miles of travel on a roadway segment; the rate is typically reported in number of crashes per hundred million vehicle-miles of travel.
critical gap
The gap (distance to nearest vehicle) in oncoming or cross traffic that a driver will accept to initiate a turning or crossing maneuver 50 percent of the time it is presented, typically measured in seconds.
cross brace
Transverse brace between two main longitudinal members.
Commonly used by railroads, a crossarm, located at the top of a utility pole, is a wooden bar to which power lines are attached; the crossarm keeps the lines separated by a sufficient distance to prevent arcing.
Crossbucks are white reflectorized X-shaped signs with "RAILROAD CROSSING" in black lettering, located alongside the roadway at railroad tracks. A crossbuck is to be viewed as a yield sign, and is a regulatory sign.
Two track switches laid back-to-back to allow trains to move from one track to another parallel track.
cross section
A section formed by a plane cutting through an object, usually at right angles to an axis.
A point along a street that is identified by striping, signage and/or signal lights that designate it as a spot for pedestrians to cross the street.