CVRIA Glossary

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Latency

A measure of time delay experienced in a system, the precise definition of which depends on the system and the time being measured. For a data element in this context, latency is the time difference between the time that data value is acquired by
the source and the time the message is transmitted.

Legacy System

Existing transportation systems, communications systems, and institutional processes.

Level of Service (LOS)

A measure of the quality of the operation of different roadway types defined in the Highway Capacity Manual (HCM). There are six LOS grades ranging from LOS A, representing optimum operation, to LOS F, representing congested or unstable flow.

Life cycle

A term used when denoting a progression through a series or sequence of differing stages of development.

Link

A Link is the locus of relations among Nodes. It provides interconnections between Nodes for communication and coordination. It may be implemented by a wired connection or with some radio frequency (RF) or optical communications media. Links implement the primary function of transporting data. Links connect to Nodes at a Port.

Link (RF)

A communications channel being used in support of application data transfer needs.

Link (traffic)

A segment of a road network. While highway links are generally separated by one data collection node (such as an RSU or a vehicle detector station), local road links tend to be limited by intersections with cross streets. Other common usages of the
word "link," such as those used in telecommunications, may also appear in the architecture.

Local (L)

One of the values for the Spatial Context Flow Characteristic. Data is local (relevant to a geographic area within ~10 minute travel distance).

Local Current (LC)

Data is local (relevant to a geographic area within ~10 minute travel distance) and current (relevant at the time of reporting for applications that do not require sub-second response).

Logical Security

Safeguards that include user identification and password access, authentication, access rights and authority levels.

Long-Range Transportation Plan (LRTP)

Also referred to as the "Transportation Plan", a document resulting from regional or statewide collaboration and consensus on a region's or state's transportation system, and serving as the defining vision for the region's or state's transportation systems and services. In metropolitan areas, this is the official multimodal transportation plan addressing no less than a 20-year planning horizon that is developed, adopted, and updated by the MPO through the metropolitan transportation planning process.

Low Emissions Zone

A geographically defined area that seeks to restrict or deter access by specific categories of high-polluting vehicles to improve the air quality within the geographic
area. The low-emissions zone can be dynamic, allowing the operating entity to change the location, boundaries, or time of the low-emissions zone.