The InSync adaptive traffic control system , developed by Rhythm Engineering is an intelligent transportation system that allows traffic signals to adapt to actual traffic demand. As of November 2015, InSync is operating in 2,300 traffic signals in 31 states and 160 municipalities in the US
InSync is a plug-and-play system that works with existing traffic control cabinets and controllers. Its two main hardware components are IP cameras and a processor, respectively referred to as “the eyes” and “the brain” of the system, respectively. Mounted video cameras determine the number of vehicles present and how long the vehicles have been waiting (also known as delay). The processor, a solid state machine, resides in the traffic controller at the intersection. The system calls up the traffic signal and coordinates its decision with other intersections.
Local Optimization InSync uses integrated digital sensors (known as cameras or the existing loop detection) to count the exact number of cars demanding service at an intersection and how long they have been waiting. Approaches are given phasing priority based on this queue and delay data. InSync’s dynamic phasing and dynamic green splits enable the traffic signals to use green time efficiently.
Global Optimization InSync creates progression along an entire corridor by using “green tunnels.” Platoons of vehicles gather and are then released through the corridor. By communicating with each other, the signals anticipate the green tunnel’s arrival so vehicles pass through without slowing down or stopping. The green tunnels’ duration and frequency can vary to best support traffic conditions. Between green tunnels, the local optimization serves the side streets and left turns.
A survey of adaptive traffic control users published by HDR, Inc. in 2010 titled “Adaptive Traffic Control Systems in the United States: Updated Summary and Comparison” in a variety of measures, including affordability, up-time, Maintenance, reduction in stops, reduction in delay and reduction in travel time.
Several speakers in the adaptive traffic control session at the ITS World Congress (Oct. 16-20, 2011, Orlando, FL) cited InSync’s entry into the market as the cause of adaptive traffic control in the US 2008-present.