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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

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Titlesort ascending Description

Or “Clearinghouse Hub”, is a node on the Clearinghouse Network, interfaces to all other Hubs on the Clearinghouse Network.

HOV Lanes

High Occupancy Vehicle lanes. Lanes typically reserved for vehicles with two or more occupants.


High-Occupancy Toll Lanes: HOT lanes are Priced Managed Lanes that use price, occupancy, and access restrictions to manage the number of vehicles traveling on them, thereby maintaining free-flow traffic conditions, even during peak travel periods. Typically, qualifying HOVs may use these limited-access highway lanes for free or at a reduced cost. Motorists in vehicles that do not meet passenger occupancy requirements may choose between the general-purpose lanes or paying for premium conditions in the HOT lanes.


Human-Machine Interface. A front-end user interface.


Heavy Goods Vehicles. Typically refers to trucks over 3.5 tons


High Capacity Road


Highway Capacity Manual. An engineering reference manual for road design.