For another meaning of the term "traffic engineering", please see telecommunications traffic engineering.

Traffic engineering is a branch of civil engineering that uses engineering techniques to achieve the safe and efficient movement of people and goods. These techniques include the use of signs, signals, and markings to move traffic more efficiently. An early traffic engineer Henry Barnes, who served as Commissioner of Traffic in many cities, including Baltimore, Maryland and New York, New York, developed coordinated traffic signal timings, so that traffic lights form green waves along major traffic arterials. Traffic flow is often described by a level of service ranging from A (which is a low density of traffic) to F (which is severely congested).

Traffic signal timing is a seemingly small subject that has a lot of legal implications. Setting a 'walk' signal for 32 seconds when the intersection is 56 feet wide means 98% of little old ladies can cross before it starts blinking don't walk. But, if you set it too slow, people run the light, hit pedestrians, speed away through the next light, and cause accidents that way. So, optimizing the safety of the neighborhood involves multiple factors like street width, lane width, number of intersecting streets, availability of electricity for a signal, number of cars per unit time and even/uneven nature of flow, number and ability of pedestrians (any school-age, blind, deaf, playing, and wheelchair-bound children in the neighborhood?), and many other factors.

Traffic engineering is closely associated with other disciplines:

• Transportation engineering
• Highway engineering
• Transportation planning
• queuing theory
• Urban planning
• Human factors

See also

• Gridlock
• Hierarchy of roads