Glossary

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• 0-9

Data

Reinterpretable representation of information in a formalized manner suitable for communication, interpretation or processing

Data Acceptance Criteria

Criteria describing the data a system accepts, often as part of a Data Distribution service. Typical meta-data includes data type, source type, location and time criteria.

Data Consumer

1) A user or system that is receiving or using data from another user or system.

2) A Physical Object that registers with and subsequently requests and receives delivery of data from a data distribution system or data warehouse.

Data Dictionary Entry (DDE)

A textual description of a data flow, accompanied by references to lower level data elements that make up the data flow. Every data flow included in the ARC-IT Functional View is defined in a data dictionary entry.

Data Exchange

The Data Exchange concept refers to a centralized mechanism that includes mechanisms to facilitate the transfer of data between different parties. Typically, this will include a published interface specification and operate as a cloud-based service. ARC-IT subsystems that include data exchange functionality are the Data Distribution System, Archived Data Center, Transportation Information Center.

Data Flow

Representations of data flowing between processes or between a process and a terminator in the ARC-IT Functional View. Graphically, a data flow is shown as an arrow on a data flow diagram and is defined in a data dictionary entry in the functional view. Data flows are aggregated to form information flows in the ARC-IT Physical View.

Data Governance

Policies and procedures that when implemented define how data is collected, stored, used and shared.

Data Lake

A centralized data repository that stores large volumes of relational and/or non-relational data in its original raw form. Data Lakes can hold a wide variety of data types at any scale. Schema-on-read ensures that any type of data can be stored in its raw form. This allows for various analytics capabilities, including some that have not been realized, to access the raw data. In contrast, a data warehouse is relational in nature. The schema or structure is predefined and optimized for SQL query operations.

Data Management

This area addresses the management of data that can be used by some or all transportation agencies and other organizations to support transportation planning, performance monitoring, safety analysis, and research. Data are collected from detectors and sensors, connected vehicles, and operational data feeds from centers.

Data Provider

1) A Physical Object that registers with and subsequently deposits data into a data distribution system or data warehouse
2) A Physical Object that supplies or transmits data to another Physical Object.

Data Store

Functional view artifact representing a reservoir in which data can be held for an indefinite period. Data stores are used in the functional view where data repositories are required to support data aggregation or archival services.

Data Warehouse

A data storage facility that supports the input (deposit) and retrieval (delivery) of clearly defined data objects. This can be designed and implemented in a variety of ways and may support publish/subscribe or query-response delivery mechanisms. In contrast to a data lake, a data warehouse will typically perform transformation, quality, and cleansing operations on the data it stores.

Decrypt

To convert unreadable, encrypted data to readable, decrypted data using a decryption algorithm and a key. See Encrypt.

Decryption Algorithm

An algorithm that takes as input ciphertext and a key and (if the correct key is provided) produces the original plaintext.

Delay

1) Additional travel time beyond some norm (e.g., LOS C in urbanized areas, LOS B elsewhere) experienced by a traveler; (for auto/truck modes -- also known as threshold delay; dlosC, dlosB);
2) Any additional travel time experienced by a traveler; (for auto/truck modes -- also known as free flow delay; dffs).

Demand

The number of persons or vehicles desiring to use a mode or facility.

Demand Management

A set of strategies that promote increased efficiency of the transportation system by influencing individual travel behavior.

Department of Environmental Protection (DEP)

The lead agency for environmental management and stewardship, protecting the state's air, water and land. DEP is divided into three primary areas: Regulatory Programs, Land and Recreation, and Water Policy and Ecosystem Restoration.

Deployability

Able to be deployed in existing roadway environments, without requiring replacement of existing systems in order to provide measurable improvements.

Digital Certificate

A digitally signed document binding a public key to an identity and/or a set of permissions.

Digital Twin

A digital representation of a physical entity or process synchronized at a specified frequency and fidelity. Data connections between the virtual and real systems enable convergence between the physical and digital states. These connections may operate in real-time or on historical data; the goal of the twin may be to optimize the performance of the physical entity or process, to simulate and predict future performance, or to improve understanding of or optimize decision making regarding the physical. A digital twin may exist at any or all phases of an entity's life cycle. Digital twins can have widely varied scope; within ITS, a digital twin might be as ambitious as a twin used to analyze and model the real-time performance of a transportation network in order to optimize future traffic control actions, or as narrow as a twin used during system development to explore the performance of a dynamic message sign.

DNS (Domain Name System)

The internet protocol for mapping host names, domain names and aliases to Internet Protocol (IP) addresses.

Driving Automation System

See Automated Driving System

Dwell time

The period of time a vehicle remains idle.

Dynamic Driving Task

All of the real-time operational and tactical functions required to operate a vehicle in on-road traffic, excluding the strategic functions such as trip scheduling and selection of destinations and waypoints.