Signal Systems are the most common and easily understood Intelligent Transportation System. Some generation of these systems are now part of the infrastructure of practically every community within North Carolina. With the rapid advancements and standardization in the computing, communications, and electronics fields, the newer systems are truly intelligent and can actually learn from and adapt to unique and new traffic phenomena as they occur.

How SMART can an intersection get?

A traffic signal can bring order to random arrivals at an intersection, reducing the delay and tension of side street motorists. The simplest signal is pre-timed, going through its preprogrammed sequence of green/yellow/red based on the time of day.

One SMART signal can sense the presence of approaching vehicles and change accordingly to further reduce the delay, emissions, and frustration. This is called an actuated signal.

A series of signalized intersections can be coordinated to provide a progressive flow along an artery, greatly reducing total trip time by “pushing” platoons of vehicles along a corridor at a steady pace. This is often called an “open network.” North Carolina’s most impressive corridor is US 70 from the capital to the beach.

A Closed Loop coordinates a group of adjacent signalized intersections, such as found in the centralized business district (CBD) of a city.

Centralized Computer Systems combine the components above to provide a metropolitan area with coordinated traffic flow. Other components which can be included are:

Ideally, Signal Systems in the future will communicate traffic information with all other Intelligent Transportation Systems within that region.

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