ITS (Intelligent Transportation Systems) is playing a major role in modern transportation construction, with ITS technology applied to roadway traffic control systems. In general, ITS involves integrating communication, control, and electronics technologies, and is used to monitor and manage traffic flow, reduce congestion, provide alternative routes to travelers, and enhance productivity to save lives, time, and money.

Roadway systems are made up of many subsystems, including Traffic Signal Control Systems, Traffic Information Display Systems, Real-time Traffic Video Monitors and Analysis Systems, and Power Substation Systems.
ATMS (Advanced Traffic Management Systems) and ATIS (Advanced Traffic Information Systems) are two of the most important aspects of ITS, and as such much of the cost for ITS implementations goes into ATMS and ATIS. By using intelligent embedded traffic controllers, traffic signals, vehicle detectors, LED display boards, and traffic surveillance cameras, a road group with several adjacent intersections can work together as one, coordinated system.

	Vehicle detectors collect traffic flow information, including volume, speed, occupancy, and then send the information to an intelligent embedded computer over a wireless transmission system.
	The embedded computer, which acts as a traffic controller, calculates and analyzes the data to determine the state of the traffic flow, and then makes control decisions—such as when to change a particular traffic signal from red to green—to avoid serious traffic jams.
	The controller sends the estimated travel time information and suggested alternative routes to the CMS (Changeable Message System) display board to alert drivers of the current traffic conditions.

A major concern is system reliability. Due to the importance of traffic control, the roadway system cannot be allowed to fail due to power failures or disconnected transmission lines. Furthermore, since the traffic situation changes from day to day, and car accidents occur unpredictably, an additional traffic monitor/surveillance mechanism should be set up for prevention and emergency response.

A roadway system designed with a solid and reliable networking infrastructure and perfect traffic control/display strategy can help to ensure higher performance. The following items are what's needed to create the roadway system.

	Real-time surveillance and capture: Video surveillance must be available to provide real-time pictures of actual traffic conditions.
	Wireless network: Traffic controllers at each intersection in the road group can synchronize the information by using wireless to transmit at least some portion of the signal over either a wireless or wired network, helping save on the cost of cabling.
	Embedded computing: The embedded computer calculates control signals in real-time to make the right traffic management decisions.
	Redundant power and network: Redundancy plays an important role in transportation systems, since it can help keep the system running non-stop.
	Extended temperature: In general, devices used for transportation automation must be able to operate in and withstand extreme temperature conditions, such as from -40 to 75°C.