Noun

Singular traffic

Plural uncountable

traffic (uncountable)

1. Pedestrians or vehicles on roads, or the flux or passage thereof.

   Traffic is slow at rush hour.

2. Commercial transportation or exchange of goods, or the movement of passengers or people.
   • 1719, Daniel Defoe, Robinson Crusoe:

     I had three large axes, and abundance of hatchets (for we carried the hatchets for traffic with the Indians).

3. Illegal trade or exchange of goods, often drugs.
4. Exchange or flux of information, messages or data, as in a computer or telephone network.

Derived terms

• traffic congestion

• traffic jam

Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel. Traffic laws are the laws which govern traffic and regulate vehicles, while rules of the road are both the laws and the informal rules that may have developed over time to facilitate the orderly and timely flow of traffic.

Organized traffic generally has well-established priorities, lanes, right-of-way, and traffic control at intersections.

Traffic is formally organized in many jurisdictions, with marked lanes, junctions, intersections, interchanges, traffic signals, or signs. Traffic is often classified by type: heavy motor vehicle (e.g., car, truck); other vehicle (e.g., moped, bicycle); and pedestrian. Different classes may share speed limits and easement, or may be segregated. Some jurisdictions may have very detailed and complex rules of the road while others rely more on drivers' common sense and willingness to cooperate.

Organization typically produces a better combination of travel safety and efficiency. Events which disrupt the flow and may cause traffic to degenerate into a disorganized mess include: road construction, collisions and debris in the roadway. On particularly busy freeways, a minor disruption may persist in a phenomenon known as traffic waves. A complete breakdown of organization may result in traffic jams and gridlock. Simulations of organized traffic frequently involve queuing theory, stochastic processes and equations of mathematical physics applied to traffic flow.