To keep in an existing operational state preserved from failure or decline of services (with minimum repair, efficiency, or validity).

Maintenance and Construction

This area addresses the monitoring, maintaining, improving, and managing of the roadway physical condition and its associated infrastructure equipment, as well as the available resources necessary to conduct these activities. This area also includes work zone management and safety, and the dissemination of maintenance and construction activities to other centers.

Major ITS Project

Any ITS project that implements part of a regional ITS initiative that is multi-jurisdictional, multi-modal, or otherwise affects regional integration of ITS systems.

Map Data Message

Provides the road geometry at an intersection.

Master Plan

A comprehensive plan to guide the long-term physical development of a particular transportation facility.


Large networks of metropolitan regions. The five major categories of relationships that define megaregions are: environmental systems and topography; infrastructure systems; economic linkages; settlement patterns and land use; and shared culture and history.


'Data about data', the information that describes content. It is information about the meaning of data, as well as the relationships among Information Objects, rules for their use and transformation, and policies on access. See Flow Characteristics.

Metropolitan Planning Area

The geographic area determined by agreement between the metropolitan planning organization (MPO) for the area and the Governor, in which the metropolitan transportation planning process is carried out.

Metropolitan Planning Organization (MPO)

The policy board of an organization created and designed to carry out the metropolitan transportation planning process for urbanized areas with populations greater than 50,000, and designated by local officials and the Governor of the state.

Metropolitan Transportation Plan (MTP)

The official multimodal, long-range transportation plan addressing no less than a 20-year planning horizon that is developed, adopted and updated by the Metropolitan Planning Organization (MPO) through the metropolitan transportation planning process.

Misbehaving user

A user who exhibits misbehavior.


Behavior that results in devices receiving information that could cause them to take incorrect actions.

Misbehavior Information

Includes Misbehavior Reports from System Users, as well as other improper System User acts, such as sending wrong message types, invalid logins, unauthorized access, incorrectly signed messages and other inappropriate System User behavior.

Misbehavior Report

Data from a System User identifying suspicious behavior from another System User that can be characterized as misbehavior.

Mission Definition

A legacy document of the National Architecture that, as the first of the technical documents, covers a broad range of ITS related issues. It contains the overall mission of ITS deployment, as well as the operational concept, which deals with specific ITS goals and objectives; ITS user groups and other stakeholders; ITS user services; and potential sources for funding, operations and maintenance. The document also defines operational requirements at the system level, user requirements, performance requirements, and program requirements.


These are vehicle types (private/personal, trucks, transit, emergency, commercial, maintenance, and construction vehicles) as well as non-vehicle-based platforms including portable personal devices (smartphones, personal digital assistants (PDAs), tablets, etc.) used by travelers (vehicle operators, passengers, cyclists, pedestrians, etc.) to provide and receive transportation information. All Physical Objects of type Vehicle or Personal are Mobile.

Mobility Index

Index of the ability of users of a system to move defined as [Ton-miles of travel] / [Vehicle-miles of travel * Average speed].


A specific form of transportation, such as automobile, subway, bus, rail, air, bicycle, or foot.


More than one travel mode including potentially the four highway modes (auto/truck, bicycle, bus/transit, and pedestrian), aviation, rail, and seaports.

Multimodal Corridor Plan

A plan that identifies interregional transportation needs involving Strategic Intermodal System (SIS), Emerging SIS, regionally significant and local facilities in a corridor.

Multimodal Transportation

The use of more than one mode to serve transportation needs in a given area.