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Glossary of Terms

IBTTA’s transportation Glossary of Terms is an ever-changing list of terms used within the transportation and tolling industry. The Glossary was updated in August 2018.  If you have suggestions for future additions, please contact us.


  Glossary of Terms

The Council of Platinum Sponsors (CoPS) TollMiner & Glossary Working Group was created to improve definitions of toll facility concepts that are used in the IBTTA TollMiner Data Visualization tool. Since the TollMiner data and structure are closely linked to the IBTTA Glossary, a review and draft update of the glossary was performed during 2021.


Review the First Draft »

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Titlesort descending Description

InterAgency Group. The E-Zpass InterAgency Group is the entity responsible for creating and administering E-Zpass, a collaboration between 21 member agencies on the East Coast of the United States that provides interoperable electronic tolling.


International Accounting Standards


International Bridge, Tunnel and Turnpike Association is the worldwide alliance of toll operators and associated industries that provides a forum for sharing knowledge and ideas to promote and enhance toll-financed and other direct-user-fee-financed transportation services.


Intelligent Cruise Control. Also known as Autonomous Intelligent Cruise Control (AICC) and Adaptive Cruise Control (ACC). Dynamic speed and distance control in relation to the vehicle in front using on-board equipment.


A Service Mark of the U.S. DOT.  IntelliDriveSM is a suite of technologies and applications using wireless communications to provide connectivity among all types of vehicles; between vehicles and roadway infrastructure; and among vehicles, infrastructure and wireless consumer devices to improve safety, mobility and environment.

InterAgency Group

IAG. The E-Zpass InterAgency Group is the entity responsible for creating and administering E-Zpass, a collaboration between 21 member agencies on the east coast of the United States, that provides interoperable electronic tolling.


A cooperative arrangement established between public and/or commercial entities (Authorities, parking lot operators, etc.) wherein tags issued by one entity will be accepted at facilities belonging to all other entities without degradation in service performance.

Interstate System Construction Toll Pilot Program

This U.S. DOT Federal Highway Administration Program authorizes up to three facilities on the Interstate System to toll for the purpose of financing the construction of new Interstate highways.


Interoperable Electronic Fee Collection - National and/or global Interoperability among various electronic toll collection technologies .


Interoperability - National and/or global Interoperability among various electronic toll collection technologies.


Individual Route Guidance. Route guidance provided to the individual user at each choice point by means of in-vehicle equipment receiving dynamic data.


Intelligent Speed Adaptation. Various concepts aimed at limiting the vehicle speed in relation to different defined speeds (static, variable or dynamic) for certain road sections via various user interfaces (informative, supportive or compulsory). Also known as Automatic Speed Adaptation (ASA).


Internal Service Fund - In government accounting, a fund used to account for goods or services given to one department by another on a cost reimbursement basis. The fund is profit and loss oriented and hence follows accrual accounting. 


International Organization for Standardization.


The organization that is responsible for issuing accounts and Private Keys to be used in the Transponder employed by a User to engage in an electronic payment service. In the US today, the Issuer is generally an Authority, but there are examples where it is a bank or credit card company in Europe. Note that the Issuer often employs a third party Account Processor (Customer ServiceType Center) to process the accounts.


Intelligent Transportation Systems. A broad range of diverse technologies, including information processing, communications, control and electronics, which, when applied to our transportation system, can save time, money and lives.


Intelligent Vehicle Highway Society (U.S.A.)