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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 March, 2016.  If you have suggestions for future additions, please contact us.


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Titlesort descending Description

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


High Capacity Road


Heavy Goods Vehicles. Typically refers to trucks over 3.5 tons


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

Hot Lanes

High Occupancy Toll (HOT) lanes are High Occupancy Vehicle (HOV) lanes that also allow access to low occupancy vehicles if drivers pay a toll. It is a type of managed lane. This allows more vehicles to use HOV lanes while maintaining an incentive for mode shifting and raising revenue. HOT lanes are often proposed as a compromise between HOV lanes and Road Pricing.

HOV Lanes

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


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