Pronunciation: [tɹˈafɪk bˈiːm] (IPA) 
The correct spelling of "traffic beam" is /ˈtræfɪk bim/. The word "traffic" is pronounced with a short "a" sound /æ/ and the "ic" is pronounced as "ick" /ɪk/. The word "beam" is pronounced with a long "e" sound /i/ and the "ea" is pronounced as "ee" /i/. Together, the two words form a compound noun that refers to the beam of light used to guide traffic, usually at night or in low light conditions.
Traffic beam refers to a component of a traffic signal system that emits a concentrated beam of light, typically in the form of a colored signal, to regulate or control the movement of vehicles and pedestrians within a roadway network. Also known as a traffic light, traffic signal, or traffic lamp, a traffic beam is commonly comprised of a vertical housing with multiple light sources, each of which emits light of a specific color, usually red, amber, and green.
The purpose of a traffic beam is to communicate information to road users, indicating when to proceed, stop, or exercise caution. The red light signals drivers and pedestrians to come to a complete stop, while the green light grants them the right of way to proceed. The amber light serves as a transition between the red and green signals, warning road users to prepare for an upcoming change. In some cases, traffic beams may also have additional signals, such as arrows, to guide turning movements.
Traffic beams are strategically positioned at intersections or other critical points along roadways to ensure efficient and safe traffic flow. They are operated in synchronization with each other, often controlled by a centralized traffic management system or manually by traffic control personnel. The clear and visible nature of traffic beams allows for effective communication of traffic regulations to road users, promoting orderly and coordinated movement while minimizing congestion and potential accidents.
The word "traffic" comes from the Middle French word "trafic" or "traffique", which referred to the movement of goods or people. Its origin can be traced back to the Italian word "traffico", meaning "trade" or "commerce", derived from the Latin word "transfretare", meaning "to carry across". Eventually, "traffic" began to refer to the movement of vehicles on roads.
As for the word "beam", it has multiple origins. The Old English word "bēam" meant "tree" or "wood" and evolved to refer to a long, sturdy piece of timber used for various purposes. In relation to traffic, the term "beam" refers to a horizontal bar or structure that spans a road and supports traffic lights, signs, or other equipment. The specific usage of "beam" in reference to traffic can be attributed to its structural resemblance and functionality.
