Glossary of Terms

  • Active Traffic Management. Active Traffic Management is a set of strategies to increase peak capacity and smooth traffic flow on highways. Techniques include variable speed limits, hard shoulder running (use of the shoulder as a travel lane during peak hours), and ramp metering.
  • Express Toll Lanes. Express toll lanes are lanes that exist on some facilities that allow a user to pay a toll for a faster and more reliable travel time. Use of express lanes is an option for drivers, not a requirement. On express lanes, all vehicles are generally tolled, but they may have free or discounted tolls for transit and other specific types of vehicles.
  • High Occupancy Toll (HOT). “HOT” stands for “High-Occupancy Toll” lane. HOT lanes combine the express toll lanes and HOV lanes concepts by allowing those who drive alone to pay a toll for using the travel lane, while high-occupancy vehicles use the lane at no cost or a reduced toll.
  • High Occupancy Vehicle (HOV). “HOV” stands for “High-Occupancy Vehicle.” HOV lanes are designated for vehicles with at least two or three people. HOV lanes encourage ridesharing through carpools, vanpools, and bus transit. An HOV lane can move more people than general purpose lanes because more passengers are traveling in each vehicle.
  • Managed Lanes. Managed lanes are a strategy to prevent congestion during periods of high demand (e.g. rush hour). Managed lanes may offer the ability to travel for free with a high-occupancy vehicle. In some instances, single-occupancy vehicles may use the managed lanes by paying a toll. Congestion is reduced when a high-occupancy or a toll-based strategy is implemented on a lane.
  • Metropolitan Transportation Plan (MTP). A fiscally constrained, long-range plan for transportation improvements across a region. It includes roadway, transit, rail, bicycle, pedestrian and other transportation projects to be implemented in the next 20 years.
  • Peak Hours. A part of the day at which traffic congestion is at its highest. During weekdays, there is typically a morning and afternoon/evening peak hour timeframe.
  • Transportation Improvement Plan (TIP). A ten-year work program that includes all regionally significant transportation projects in the MPO planning area. The TIP includes projects for all modes of transportation included in the MTP. All projects in the TIP must be consistent with the adopted Metropolitan Transportation Plan (MTP).
  • Triangle Region. For the purposes of this study it is the areas bound by the Capital Area Metropolitan Planning Organization (CAMPO) and the Durham-Chapel Hill-Carrboro Metropolitan Planning Organization (DCHC MPO).