Adaptive Control - A type of traffic management system that dynamically adjusts the signal timing to the traffic conditions.
Average Daily Traffic (ADT) - Daily number of cars that travel through an area, moving in both directions, typically represents the average over a year.
Alignment - Proposed route.
Arterial - A class of street allowing significant traffic movements for travel between major points and providing regional connectivity, with speeds and traffic volumes higher than local streets.
Advanced Traffic Management Systems (ATMS) - Remotely operated traffic management system for monitoring and managing operations of a freeway system and arterial streets. Major elements of the system include surveillance, communications, and controls.
Auxiliary Lane - Lane of typically short length added to help traffic merging onto or exiting off of the mainline highway, usually from one on-ramp to the following off-ramp.
Bore - Tunnel.
Bus Rapid Transit (BRT) - A type of fixed route bus service that includes features to increase the speed of the bus, such as bus only lanes, bus priority at traffic signals, less frequent bus stops, and fare collection at bus stops.
Chokepoint Projects - Type of freeway improvement project that is implemented at a specific location to alleviate the bottleneck. Projects tend to be relatively low cost, improvements include adding additional exit or merge lanes and/or widening off and on ramps.
Collector Distributor Road - Collector Distributor Roads provide a separate roadway for traffic to merge and diverge off of the mainline highway or freeway.
Community-based Shuttles - Transit service providing localized service, connecting neighborhoods and major destinations while linking with the regional transit network.
Cut and Cover Tunnel - A type of tunnel construction for shallow tunnels where a trench is excavated and roofed over.
Direct Connector Lane - A facility that directly connects two different highways, commonly found linking two freeways.
Direct HOV Connectors - Provides direct connections between High Occupancy Vehicle (HOV)/carpool lanes on different freeways without the need for exiting the carpool lane to change freeways.
Draft and Final Evaluation Reports - The reports that are prepared near the conclusion of a major investment study which detail the comparison of the benefits, impacts and costs of the final set of alternative transportation improvement strategies. The Final Evaluation Report also documents the selected Locally Preferred Strategy.
Express Bus - Relatively long-distance fixed-route buses providing direct point-to-point service with minimal stops that often utilize high-occupancy vehicle (HOV) lanes on Orange County Freeways.
Fixed Guideway Transit - Any transit service that operates on exclusive or controlled rights-of-way or rails.
Fixed Route Service - Bus service that is operating along a defined route on a defined schedule.
General Purpose Lane - A traffic lane that can be used by all types of vehicles including single occupant autos, carpools, trucks and motorcycles.
Grade Separated Facility - Highways in which different movements or directions of travel take place on different levels, above or below.
Grade Separation - The separation of facilities by means of one of the facilities being elevated above or trenched below the other.
Green Time - The amount of time a signal remains green.
High Occupancy Vehicle (HOV) - Vehicles with more than one occupant.
High Occupancy Toll (HOT) - Single-occupant vehicles are allowed to pay to use the HOV lane.
Initial Screening - The step in a major investment study in which the initial set of alternative transportation improvement strategies (typically 8-10 alternatives) are assessed based on their benefits, impacts and costs. They are then screened down to the final set of alternative strategies (typically 3-4 alternatives) that are deemed the “best” and subjected to more detailed assessment in the technical and environmental analysis.
Lane Balancing - New lanes added to balance the number of lanes in opposing directions of travel.
Limited Access Roadway - A road to which access from adjacent properties or arterials is limited in some way (such as a freeway).
Locally Preferred Strategy (LPS) - The combination of transportation improvement projects and services that has consensus support to move forward towards implementation at the conclusion of a major investment study. It is derived from the final, reduced set of alternative strategies that are analyzed as part of the major investment study.
Long Range Transportation Plan (LRTP) - The county-wide plan for improving transportation over the next 25 years.
Managed Lanes - Designated freeway or roadway lanes that use a variety of operational actions to move traffic more efficiently.
Master Plan of Arterial Highways (MPAH) - The county-wide plan administered by OCTA that defines a county-wide circulation system insuring coordination of roadway planning among local agencies.
Mixed Flow Lane - General purpose highway lane available to all users.
Multimodal - Refers to the availability of multiple transportation options, such as train, bicycle, automobile, bus, especially within a system or corridor.
Multimodal Centers - A place where connections are made between transportation options such as local transit buses, express buses, automobiles, and trains.
NB - Northbound direction.
Pre-Scoping - The phase of the major investment study in which information is gathered, assessed and reported regarding transportation system performance in the study area and the factors affecting performance. Pre-Scoping leads to the development of the mobility problem and purpose and need for transportation improvements.
Purpose and Need Statement (P/N) - Provides the goals and objectives to be addressed by proposed transportation improvements; the reasons for undertaking transportation system improvements.
Rail-feeder Bus Service - Bus service specifically designed to take passengers from rail stations to and from surrounding areas.
Scoping - The phase of a major investment study when input is sought on the mobility problems, as well as purpose and need for transportation improvements and when the initial set of alternatives are developed.
Technical and Environmental Analysis - The phase of a major investment study when the final set of alternative strategies are analyzed to determine their comparative benefits, impacts and costs.
Transit - May include urban light or heavy rail, commuter rail, bus, express bus, bus rapid transit, “paratransit” like small buses available on advance call-in basis for mobility-challenged individuals, etc.
Transit Oriented Development (TOD) - A type of land use development that encourages transit use by being pedestrian “friendly” and having mixed-land uses such as residential, retail, and office within walking distance of each other and frequent transit services.
Transit Transfer Center - Where different modes of transit meet at the same location, providing easy transfers between modes.
Transportation Systems Management (TSM) - Transportation facility management strategies that improve the roadway system’s performance. Examples include: providing special lanes for buses and carpooling vehicles; the use of Changeable Message Signs, ramp metering, development of regional traffic management centers or the use of reversible traffic lanes.
Transportation Demand Management (TDM) - General term for strategies that result in more efficient use of transportation resources. Examples include: flex time, car sharing, strategies for improving bicycle transport, pedestrian improvements and ridesharing.
Truck Lane - A dedicated lane for the exclusive use of trucks.
Variable Message Signing - Electronic Message Boards that are changeable and provide information to the motorist on the spot also known as changeable message signs or CMS.