Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads/sidewalks) for travel and transportation.
Traffic lights, traffic signals, or stoplights – also known as robots in South Africa, Zambia, and Namibia – are signaling devices positioned at road intersections, pedestrian crossings, and other locations in order to control the flow of traffic.
Traffic engineering is a branch of civil engineering that uses engineering techniques to achieve the safe and efficient movement of people and goods on roadways. It focuses mainly on research for safe and efficient traffic flow, such as road geometry, sidewalks and crosswalks, cycling infrastructure, traffic signs, road surface markings and traffic lights. Traffic engineering deals with the functional part of transportation system, except the infrastructures provided.
A variable-message sign or message board, often abbreviated VMS, VMB, CMS, or DMS, and in the UK known as a matrix sign, is an electronic traffic sign often used on roadways to give travelers information about special events. Such signs warn of traffic congestion, accidents, incidents such as terrorist attacks, AMBER/Silver/Blue Alerts, roadwork zones, or speed limits on a specific highway segment. In urban areas, VMS are used within parking guidance and information systems to guide drivers to available car parking spaces. They may also ask vehicles to take alternative routes, limit travel speed, warn of duration and location of the incidents, inform of the traffic conditions, or display general public safety messages.
A cloverleaf interchange is a two-level interchange in which all turns are handled by slip roads. To go left, vehicles first continue as one road passes over or under the other, then exit right onto a one-way three-fourths loop ramp (270°) and merge onto the intersecting road. The objective of a cloverleaf is to allow two highways to cross without the need for any traffic to be stopped by traffic lights. The limiting factor in the capacity of a cloverleaf interchange is traffic weaving.
South Gippsland Freeway is a short freeway linking Dandenong in Melbourne's south–east to other south–eastern destinations, including the Mornington Peninsula and the Gippsland region. The freeway bears the designation M420.
A diamond interchange is a common type of road junction, used where a controlled-access highway crosses a minor road.
A partial cloverleaf interchange or parclo is a modification of a cloverleaf interchange.
A reversible lane is a managed lane in which traffic may travel in either direction, depending on certain conditions. Typically, it is meant to improve traffic flow during rush hours, by having overhead traffic lights and lighted street signs notifying drivers which lanes are open or closed to driving or turning.
The road hierarchy categorizes roads according to their functions and capacities. While sources differ on the exact nomenclature, the basic hierarchy comprises freeways, arterials, collectors, and local roads. Generally, the functional hierarchy can more or less correspond to the hierarchy of roads by their owner or administrator.
A limited-access road, known by various terms worldwide, including limited-access highway, dual-carriageway, expressway, and partial controlled-access highway, is a highway or arterial road for high-speed traffic which has many or most characteristics of a controlled-access highway, including limited or no access to adjacent property, some degree of separation of opposing traffic flow, use of grade separated interchanges to some extent, prohibition of slow modes of transport, such as bicycles, horse-drawn vehicles or ridden horses, or self-propelled agricultural machines; and very few or no intersecting cross-streets or level crossings. The degree of isolation from local traffic allowed varies between countries and regions. The precise definition of these terms varies by jurisdiction.
In the field of road transport, an interchange or a grade-separated junction is a road junction that uses grade separations to allow for the movement of traffic between two or more roadways or highways, using a system of interconnecting roadways to permit traffic on at least one of the routes to pass through the junction without interruption from crossing traffic streams. It differs from a standard intersection, where roads cross at grade. Interchanges are almost always used when at least one road is a controlled-access highway or a limited-access divided highway (expressway), though they are sometimes used at junctions between surface streets.
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms include throughway or thruway and parkway. Some of these may be limited-access highways, although this term can also refer to a class of highways with somewhat less isolation from other traffic.
In traffic engineering, there are regional and national variations in traffic light operation. This may be in the standard traffic light sequence or by the use of special signals.
The Sydney Coordinated Adaptive Traffic System, abbreviated SCATS, is an intelligent transportation system that manages the dynamic timing of signal phases at traffic signals, meaning that it tries to find the best phasing for a traffic situation. SCATS is based on the automatic plan selection from a library in response to the data derived from loop detectors or other road traffic sensors.
STREAMS Integrated Intelligent Transport System is an enterprise traffic management system designed to operate in the Microsoft Windows environment. Like most traffic management systems, STREAMS is an array of institutional, human, hardware, and software components designed to monitor, control, and manage traffic on streets and highways. Advanced traffic management systems come under the banner of ITS. ITS is the application of information and communications technology to transport operations in order to "reduce operating costs", "improve safety" and "maximize the capacity of existing infrastructure". STREAMS provides traffic signal management, incident management, motorway management, vehicle priority, traveler information, flood monitoring and parking guidance within a single integrated system is what the product says. STREAMS is developed by Transmax.
Active traffic management is a method of increasing peak capacity and smoothing traffic flows on busy major highways. Techniques include variable speed limits, hard-shoulder running and ramp-metering controlled by overhead variable message signs. It has been implemented in several countries, including Germany, the United Kingdom, Canada and the United States.
Paramics is traffic microsimulation software, originally developed by Quadstone Ltd. There is a related pedestrian microsimulation product called the Urban Analytics Framework.
Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.
A managed lane is a type of highway lane that is operated with a management scheme, such as lane use restrictions or variable tolling, to optimize traffic flow, vehicle throughput, or both. Definitions and goals vary among transport agencies, but managed lanes are generally implemented to achieve an improved operational condition on a highway, such as improving traffic speed and throughput, reducing air pollution, and improving safety. Types of managed lanes include high-occupancy vehicle (HOV) lanes, high-occupancy toll lanes, express toll lanes, reversible lanes, and bus lanes. Most managed lane facilities are located in the United States and Canada, although HOV and bus lanes can be found in many other countries; outside of the US and Canada, many countries use active traffic management that manage all lanes of a highway.
