The Frustration of Archaic Traffic Control Systems

By Robert Hult | March 19, 2019

Emerging traffic management equipment represents a bright new market for advanced sensors and many types of related connectors.

traffic control systems

I like to consider myself reasonably adjusted to the challenges of living in the 21st century, except one: We continue to labor under the dictates of traffic control systems technology that dates from the early part of the last century. My level of frustration begins to spike when I am waiting at a red light while watching absolutely no cross traffic for the entire period of a pre-determined timer cycle.

Engineers were able to send a space probe four billion miles into orbit around an asteroid only 1,600 feet in diameter. Perhaps we could design a traffic control system that could measure traffic a mile or so down the road and make intelligent traffic light decisions to maximize rather than impede flow. There is no doubt that forcing cars to stop at every intersection is highly fuel inefficient, as acceleration consumes more gas and generates more noxious emissions. The amount of time it takes to get through a gauntlet of uncoordinated traffic lights is highly dependent on the timing cycle at each intersection. Excessive delay can encourage running the light, which increases the chances of a crash.

The traffic management equipment industry is ripe for disruption, given that the first three-signal traffic light was installed in 1920. With all the incredible advances in communication, transportation, and computing over the last nearly 100 years, traffic controls seem to have been passed by. By one estimate, 97% of all traffic lights in the US are still based on timing technology. To some degree, the resistance to change is due to public sector purchasing that tends to continue buying equipment that is compatible with the existing infrastructure and which may have a 10- to 20-year service life. These analog systems have a proven track record, which provides little incentive to introduce new technology. Another challenge is the fact that cities, states, and countries may require compliance to specific standards, which further limits options.

Traffic control equipment is a niche industry dominated by a few large manufacturers, including Siemens, Econolite, Novax, Peek Traffic, and McCain. Additional suppliers offer compatible controller modules for use in open architecture applications. Traffic control systems represent a significant expense that may top $500,000 per intersection.

Rather than continue to grouse, I decided to explore the world of traffic control equipment and discovered that there is much more than a sinister clock inside those large controller cabinets.

traffic control systems control panel box

Traffic light control panel box. Image by

I have often wondered why those enclosures sitting at every intersection are so large. My laptop has much more smarts and takes up a fraction of the space. Open one of those cabinets, however, and you’ll quickly learn there is a lot going on inside. With the absolute mandate for fail-safe operation, every component is designed for close to mil/aero reliability. In addition to the actual controller, enclosures may include connections to up to 64 external sensors, a bank of relays, video processors, uninterruptable power supplies, copper, fiber, and wireless central office communication modules, test and validation tools, traffic data collection devices, conflict monitors, modems, police and fire override panels, maintenance panels, message generators, lights, fans, thermostats, and lots of cables.

In order to insure compatibility and performance, equipment is built to NEMA TS 2-2016 standards.

traffic control systems user interface

Siemons traffic control system user interface

The heart of these systems is the controller, which includes a user interface for programming and test.

traffic control systems assembly drawing

In order to communicate, controllers are studded with a wide variety of separable interfaces, including industrial plastic circulars, Ethernet (RJ45), USB, 104 position rectangular power connector, and multiple configurations of D-subminiature connectors.

pluggable modules for traffic control systems

McCain pluggable modules for traffic control systems

Controllers are often designed to accept a series of pluggable modules to allow customization to specific requirements of an intersection.

Typical Eurocard DIN 41612 two-piece backplane connectors allow modules to plug into the rear of the controller.

Although the environment in which this equipment must survive is incredibly harsh, unsealed connectors are used, as the enclosure provides isolation from water, salt spray, and corrosive gases. Internal electronics are rated to survive -40°F to 176°F and 0-95% relative humidity.

traffic control systems wiring

Wires coming in from sensors and other peripherals are often field-terminated with DIN rail and barrier terminal blocks, which require no special operator tools other than a wire stripper and screwdriver.


optical cable link for traffic control systems

Links to a central office for control of a network of intersections are often made via a fiber optic link

Links to a central office for control of a network of intersections are often made via a fiber optic link. In order to address the reality that these enclosures are subject to being hit by a car, special fiber optic breakaway connectors have been developed that allow quick recovery after an accident.

Despite its glacial adoption of new technology, the traffic control industry and governments have been exploring ways to modernize traffic management. Cam-driven mechanical switches have been replaced with solid state switches. Sensors embedded in the road detect cars in a turn lane, but cars often remain subject to predetermined wait times. In 1980 the Split Cycle Optimization Technique (SCOOT) introduced the ability to automatically adjust timing cycles to local traffic conditions. In 1987 the National Cooperative Highway Research Program was created under the US Department of Transportation. Its objective was to study ways to relieve urban traffic congestion. More recently, the Intelligent Transportation System (ITS) software platform combines the power of computational, sensing, and communication technologies to more efficiently manage traffic in the US and Europe. The Advanced Traffic Management System (ATMS) enhances control capabilities by sending real-time traffic data from cameras, speed sensors, and volume flow to a transportation management center where signaling cycles can be adjusted. In the meantime, urban populations and resulting traffic volumes have grown.

At some point, fully autonomous vehicles will communicate among themselves and with an intelligent central management system to enable high-speed transportation with no human intervention. We are starting to see the introduction of real-time adaptive traffic control systems, which will pave the way to the future of automotive transportation. The Surtrac system from Rapid Flow Technologies utilizes artificial intelligence to optimize flow based on second-to-second conditions. It collects data from a variety of detectors and builds a constantly adjusting model that calculates the most efficient way to move traffic through an intersection, corridor, or complex grid. Travel time has been reduced by 25%, waiting time at intersections has been reduced by 40%, stops reduced by 30%, and 20% fewer emissions have been produced at intersections using this system.

Individual states have become more aggressive in developing solutions to improve traffic flow. The RoadX program sponsored by the Colorado Department of Transportation is a platform for partnering with global and local transportation resources with the objective of moving traffic management systems into the 21st century.

Automated traffic management using artificial intelligence will be highly dependent on the transmission of quality real-time data generated by a network of ruggedized sensors.

embedded roadway sensors for traffic control systems

Embedded roadway traffic sensors

The standard wire loop sensor embedded in the road will be supplemented with continuous streams of video data. Automated video recognition software can not only calculate speed and volume, but also identify specific types of vehicles, from large trucks to motorcycles, each of which contribute differently to traffic congestion levels.

Additional high-performance ultrasonic, radar, and RFID sensors located along the road will require ruggedized and environmentally sealed connectors. With thousands of sensors installed throughout a major network, data collection and analysis will result in decentralization of control and evolve to more edge computing architecture. With enhanced security, a network of sensors connected as IoT devices would simplify their deployment and speed data exchange. Data communication via emerging 5G networks would address requirements for reduced latency.

All of these advances will result in demand for computing systems with greater capacity, computational speed, and real-time communication resources. Emerging traffic management equipment represents a bright new market for advanced sensors and many types of related connectors.

Like this article? Check out our other automotive, new technology, and 2019 articles, and our Transportation Market page.

Robert Hult
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