Glossary

Automatic Vehicle Identification (AVI): A technology system using transponders on vehicles and outside sensors to determine if vehicles on toll lanes are carrying a valid transponder and what the vehicle’s classification is (truck vs. passenger car, SOV vs. HOV). This system also processes the appropriate toll transaction based on the information.

Benefit-Cost Ratio (BCR): The ratio of a project’s present value benefits to its present value costs. The BCR is useful for comparing projects of different scale or financial size since it assesses economic efficiency.

Closed Circuit Television (CCTV): A video monitoring and security system used to provide continuous traffic monitoring by the facility operator along the length of the facility and particularly at points of entry and tolling locations.

Detector Loops (Loop Detector Amplifiers): An AVC system component imbedded in the pavement and used to detect and classify the type of vehicles passing over them. The loops are linked to the lane controller and can be used individually to count traffic or to trigger the violation enforcement cameras or in tandem to measure vehicle speeds.

Differential Pricing (Variable Pricing): Time-of-day pricing and tolls that vary by other factors like facility location, season, day-of-week, or air quality impact.

Dynamic Pricing: Tolls that vary in real time in response to changing congestion levels, as opposed to variable pricing that follows a fixed schedule.

Economic Rate of Return (ERR): The economic rate of return (ERR), sometimes referred to as the internal rate of return, gives the effective discount rate for which the project’s benefits would just equal its costs, in present value terms. In other words, it is the discount rate that yields a BCR of 1.0.

Electronic Toll Collection (ETC): Systems deploying various communications and electronic technologies to support the automated collection of payment at toll booths and other collection points. Collectively, the application of these technologies increase system throughput, improve customer service, enhance safety, and reduce environmental impacts.

Express Lanes: A lane or set of lanes physically separated or barriered from the general-purpose capacity provided within major roadway corridors. Express lane access is managed by limiting the number of entranced and exit points to the facility. Express lanes may be operated as reversible flow facilities or bi-directional facilities.

E-ZPass: An electronic toll collection technology deployed by a regional consortium of transportation agencies in Delaware, New Jersey and New York. The technology is compatible with similar systems used by tolling agencies in several northeastern states. Plans call for the deployment of E-ZPass on more than 700 toll lanes along 415 miles of roads, tunnels and bridges in the Northeast United States.

Fees for Entering: These are tolls charged to vehicles entering a particular facility or an area but which do not depend on the distance traveled on the facility or in the area.

High-Occupancy Toll Lanes (HOT lanes): Managed, limited-access, and normally barrier-separated highway lanes that provide free or reduced cost access to HOVs, and also make excess capacity available to other vehicles not meeting occupancy requirements at a market price.

High-Occupancy Vehicle (HOV): A passenger vehicle carrying more than a specified minimum number of passengers, such as an automobile carrying more than one or more than two people. HOVs include carpools and vanpools, as well as buses.

HOV lane: an exclusive traffic lane or facility limited to carrying HOVs and certain other qualified vehicles.

Inherently Low Emission Vehicles (ILEV): Alternative fuel, clean air vehicles. Certain states (e.g. California) have authorized the use of ILEVs in HOV lanes regardless of occupancy (Assembly Bill 71). Related terms include Zero-Emission vehicles (ZEVs), Ultra-Low-Emission (ULEV), and Super-Ultra-Low-Emission (SULEV) vehicles powered by alternative fuels.

Incident Management: Managing forms of non-recurring congestion, such as spills, collisions, immobile vehicles, or any other impediment to smooth, continuous flow of traffic on freeways.

Infrared Light Curtains: An ETC system component installed in pairs to sense the separation between two vehicles passing through a lane, as well as height depending on the number of beams deployed. The information passed on to the lane controller is used in conjunction with the loop detectors to support the correct grouping of axles and to identify large trucks or vehicles pulling trailers.

Intelligent Transportation Systems (ITS): A broad range of diverse technologies such as information processing, communications, control, and electronics which can help transportation systems in many ways, including congestion management.

Interoperability: The ability to provide of reciprocal privileges for users of electronic toll collection systems on other facilities equipped with ETC systems.

Lane Controller: A micro processor ETC component that coordinates the activities of all equipment in a single lane and generates the transactions assigned to individual customers using that lane.

Lane Management Tools:

• Access – Limiting or metering vehicle ingress to the lane or spacing access so that demand cannot overwhelm HOT lane capacity. See also Limited Access.
• Eligibility – Limiting lane use to specific types of users, such as HOVs, motorcycles, low emission vehicles, or trucks. For most typical HOT lane settings, eligibility requirements would be used during selected hours or at specific access ramps.
• Pricing – Imposing a user fee on a lane that helps regulate demand by time of day or day of week. The fee increases during periods of highest demand.

Level-of-Service (LOS): Also knows as “Traffic Service,” LOS is a qualitative measure describing operational conditions within a traffic stream. LOS assesses conditions in terms of speed and travel time, freedom to maneuver, traffic interruptions, comfort and convenience, and safety. Six levels of service are defined by letter designations from A to F, with LOS A representing the best operating conditions, and LOS F the worst.

Limited Access: Access management used to restrict entry to a facility based upon facility congestion levels or operational condition, such as the presence of an accident or maintenance activities. Access may be restricted by 1) metering signals, or 2) limiting the number of entrances and exits. Some restricted access lanes include HOV priority.

Managed Lane: A lane or lanes designed and operated to achieve stated goals by managing access via user group, pricing, or other criteria. A managed lane facility typically provides improved travel conditions to eligible users.

Metropolitan Planning Organization (MPO): Federally mandated regional organizations responsible for comprehensive transportation planning and programming for in urbanized areas. Work products include the Transportation Plan, the Transportation Improvement Program, and the Unified Planning Work Program.

Mileage-Based Fee: A vehicular toll based on the vehicle miles traveled (VMT) in the jurisdiction.

Mixed-flow: Combined flow of HOV vehicles and SOV vehicles.

Motor Vehicle Fuel Tax: Federal and state taxes levied on gasoline and other fuels.

Open Road Tolling: Fully automated electronic tolling in an open road environment allowing vehicles to travel at normal speeds when passing through toll collection points.

Price Elasticity of Demand: A measure of the sensitivity of demand for a commodity to a change in its price. It equals the percentage change in consumption of the commodity that results from a one-percent change in its price. The greater the elasticity, the more price-sensitive the demand for the commodity.

Queue Jump: Elevated ramps or at-grade lanes that can be used by motorists stopped in traffic to bypass congestion.

Reversible Flow: Lanes than can be operated in reverse direction to reduce congestion during certain peak periods.

Revenue Neutral: Revenue-neutral pricing strategies involve rebating some or all of the revenue generated by pricing to toll payers, where generating revenue is not an objective of value pricing.

Road Pricing: An umbrella phrase that covers all charges imposed on those who use roadways. The term includes such traditional revenue sources as fuel taxes and license fees as well as charges that vary with time of day, the specific road used, and vehicle size and weight.

Single Occupant Vehicle (SOV): A vehicle occupied by only one person.

Time-of-day Pricing: Facility tolls that vary by time-of-day in response to varying congestion levels. Typically, such tolls are higher during peak periods when the congestion is most severe. Many sectors of the economy (telephone, electric utilities, and airlines) use such pricing to manage demand within the available capacity.

Toll Road: A road or section of road where motorists are charged a fee (or toll).

Toll Violation Camera: Fixed, short range, still cameras used to obtain single frame pictures which are deployed in individual lanes at tolling points. Toll violation cameras are aimed and focused to obtain images of the license plates of violating vehicles.

Transponder: An electronic tag mounted on a license plate, built into a vehicle, or placed on the dashboard. The tag is read electronically by an electronic tolling device that automatically assesses the amount of the user fee.

Transportation Demand Management (TDM): Actions that improve transportation system efficiency by altering transportation system demand using such strategies and facilities as: pricing, ridesharing; park-and-ride facilities, transit friendly development / zoning; and employer-based programs—such as staggered work hours and telecommuting. TDM programs improve the efficiency of existing facilities by changing demand patterns rather than embarking on capital improvements.

Transportation System Management (TSM): Integrated protocols and computerized ITS systems used to manage roadway and transit facilities. TSM techniques improve system capacity without physical expansion or behavioral changes. Typical TSM measures involve continuous management and operation of traffic systems, and utilize integrated traffic control systems, incident management programs, and traffic control centers.

Treadle: A pressure-sensitive device inserted in the pavement designed for directional counting of vehicle axles passing over them. These sensors are used as inputs to the lane controller to provide information on axle count and vehicle direction of travel, depending on the order in which the stripes are hit.

User Management: User management defines how and which types of users can utilize a facility, such as HOV occupancy requirements, access points, barrier separation, and user fees. Restrictions may vary by time of day or day of the week.

Value Pricing: Value pricing is a concept that uses monetary incentives to manage congestion during peak travel periods on tolled highways and crossing facilities.

Variable Message Signs (VMS): Electronic signage that employs ITS technology and centralized control systems to change messages in real time, providing motorists with timely and useful information.

Vehicle Hours Traveled (VHT): The total vehicle hours expended traveling on the roadway network in a specified area during a specified time period.

Vehicle Miles Traveled (VMT): The measurement of the total miles traveled by all vehicles in a specified area during a specified time.

Vehicle Enforcement Systems (VES): Manual and computer systems used to enforce vehicle and motorist compliance with the usage guidelines for HOT lanes.

Vehicle Separators/Profilers: An AVI system component located on a gantry or at the side of a lane. They perform functions similar to light curtains. The class of vehicles is determined based on the profile of the passing vehicle.

Video Surveillance: The use of pan-tilt-zoom, steerable moving picture cameras to survey a toll plaza, ETC collection area, or a segment of roadway to monitor for incidents.

Several glossary definitions were prepared by the Transportation Research Board’s Joint Subcommittee on Pricing