ACDSS® is our flagship adaptive control decision support system that provides real-time traffic analysis and recommendations to traffic management centers in more than eight cities around the world. The system works within TransCore’s TranSuite signal control software. In addition to large-scale deployments in Manhattan and Riyadh, we have worked with several cities around North America to deploy the system in strategic locations. The system has a flexible architecture, has policy inputs, is data-driven, and provides operator-in-the-loop functionality.
In cases where traffic experiences unpredictable changes, it can be difficult for cities to manage congestion. Adaptive systems offer traffic management centers (TMCs) a way to perform real-time analysis and modification to traffic signal timings that can reduce congestion and improve vehicle travel time instantaneously. As opposed to a fully automated traffic control system, our Advanced Adaptive Control with integrated Decision Support System (ACDSS®) was developed with the idea that operators can sit in the driver’s seat, review and approve or override the system's recommendations, as needed.
In 2005-2006, we had an opportunity to build a system for New York City’s Department of Transportation (NYCDOT) from scratch. They had a vision of what they wanted: a system that could adapt signal timing to an unpredictable or unforeseen event. They did some market research themselves, but felt that the systems out there were not necessarily what they wanted.
KLD had always been working on signal control algorithms and optimizations and had a lot of knowledge base and brainpower related to this in our DNA when the city suggested this, so we worked collaboratively with NYCDOT to create this this system.
We developed ACDSS® to work with TransCore’s TranSuite, which is a tool for operators to manage and operate a city’s traffic signals. ACDSS® runs as a module within TranSuite as a mechanism for two way data exchange. Based on data it receives from the field, the system performs its optimizations calculations and develops recommendations. Depending on the operator's decision, the results of those optimizations are sent back to the field through TranSuite.
After our successes in rolling out the system in a pilot project on Staten Island and scaling it up for entire districts in Midtown Manhattan and Riyadh, we have worked with TransCore to develop more strategic deployments of the system for other cities.
Transportation agencies have carefully selected where they want to deploy adaptive signal control. All of these involve a “pilot corridor” that experiences unpredictable changes to traffic, because that is where adaptive signal control would provide the most benefit. These pilot corridors have typically been adjacent to either a freeway that experiences a lot of diverted traffic. When that happens, the system can identify and make changes as needed at several intersections along the corridor. Depending on the specifics of each site, like schools or stadiums that might drive variable traffic flow, we cater our algorithms.
Regardless of whether an agency wants a “set it and forget it” system or wants to be much more involved in understanding what the system is doing, they are very appreciative of the support we’ve given them. We are exploring potential collaborations in the future with many agencies to expand the deployment for other needs.
Some of the biggest challenges that we help agencies work through include maintenance of field infrastructure (any adaptive system depends upon field data) and evaluation (adaptive systems are meant to respond to the non-typical or non-recurring congestion pattern, so it can be hard to measure benefits when there are periods of low activity in the pilot corridor).
