Researchers Suggest Organic Computing Approach to Traffic Light Control
28 June 2009
An organic computing-based approach to traffic light control, might help solve the problem of controlling road traffic in congested areas and avoid traffic jams and gridlock, according to research published this month in the International Journal of Autonomous and Adaptive Communications Systems.
The organic approach to traffic light control in urban areas presented by Holger Prothmann of the Karlsruhe Institute of Technology and colleagues there and at Leibniz Universität Hannover, Germany, exhibits adaptation and learning capabilities, allowing traffic lights to autonomously react on changing traffic conditions. The coordination mechanism for neighboring traffic lights relies solely on locally available traffic data and communication among neighboring intersections, resulting in a distributed and self-organizing traffic system for urban areas.
The environmental and economic importance of traffic control systems combined with the distributed nature of traffic nodes and their constantly changing traffic demands make traffic light control an ideal test case for organic computing approaches.—Holger Prothman
The authors are members of the Organic Traffic Control Collaborative (OTC2), a joint project between the two universities. A prior project developed an architecture for an adaptive learning node controller. This architecture was extended to enable collaboration among the node controllers—a prerequisite for a network-wide optimization.
Organic Computing is based on the presence of large collections of autonomous systems, which are equipped with sensors and actuators, are aware of their environment, can communicate freely, and can organize themselves in order to perform the actions and services that seem to be required.
The presence of networks of intelligent systems in our environment opens fascinating application areas but, at the same time, bears the problem of their controllability. Hence, we have to construct such systems—which we increasingly depend on—as robust, safe, flexible, and trustworthy as possible. In particular, a strong orientation towards human needs as opposed to a pure implementation of the technologically possible seems absolutely central. In order to achieve these goals, our technical systems will have to act more independently, flexibly, and autonomously, i.e. they will have to exhibit life-like properties. We call those systems “organic”. Hence, an “Organic Computing System” is a technical system, which adapts dynamically to the current conditions of its environment. It will be self-organizing, self-configuring, self-optimizing, self-healing, self-protecting, self-explaining, and context-aware.—OTC2
In the case of an urban traffic system, the sensors would be closed-circuit TV cameras mounted on road gantries and other places while the controllers, or actuators, would be traffic lights, which can effectively start and stop the flow of traffic.
Currently, traffic lights either have fixed timer controls or a centralized, control system. The widely used Split, Cycle and Offset Optimization Technique (SCOOT) is popular with those responsible for traffic control. It computes a single cycle time for all intersections, splits this cycle time into green times for each intersection and then adjusts offset times in order to minimize waiting times. SCOOT’s primary aim is keep traffic flowing smoothly and pedestrians safe. Modern traffic-responsive Urban Control (TUC) additionally takes public transport into account.
However, although these systems have been developed over many years, they do have several technical shortcomings and traffic jams do occur more frequently than drivers would like because problems with flow control. Fixed timers are obviously flawed as they do not respond to traffic itself and even centralized systems cannot respond optimally to the changes in traffic movements out on the roads. This leads to jams and waste drivers’ time, vehicle fuel, and to higher levels of localized pollution in towns and cities than might otherwise be present.
Prothmann and his colleagues used the organic computing approach to develop a decentralized traffic control system and compared its impact on traffic flow with a conventional system. The organic approach is based on industry-standard traffic light controllers. These have been adapted to have an observer/controller architecture that allows the traffic light to respond to traffic flow and to pass on information to the other traffic lights on neighboring roads.
Tests at busy junctions in Hamburg demonstrated that the average number of vehicle stops can be cut significantly, delays avoided, and journey times reduced, all of which has benefits for drivers, pedestrians and city dwellers, and, in terms of fuel use and pollution, the environment.
Holger Prothmann, Jürgen Branke, Hartmut Schmeck, Sven Tomforde, Fabian Rochner, Jörg Hähner, Christian Müller-Schloer (2009) Organic traffic light control for urban road networks. Int. J. Autonomous and Adaptive Communications Systems, 2, 203-225 doi: 10.1504/IJAACS.2009.026783
Organic Traffic Control research overview
"Tests at busy junctions in Hamburg demonstrated that the average number of vehicle stops can be cut significantly, delays avoided, and journey times reduced, all of which has benefits for drivers, pedestrians and city dwellers, and, in terms of fuel use and pollution, the environment."
This makes a lot of sense. What doesn't make sense is sitting at a red light with your engine idling & there is little/no cross traffic. Series of lights that are synced for weekday rush hour traffic often have very different traffic patterns after hours & on weekends. Hopefully they will get the technology to work.
Posted by: ejj | 28 June 2009 at 10:46 AM
Yes this does make a lot of sense and should not be very difficult.
Organic Computing is just like Fuzzy Logic, but with less fur.
I suspect there has been little "need" recognized up until now - as evidenced by traffic restrictions like safe zones for workers, still up on Weekends.
And these traffic cameras should be able to synchronize the lights for the lone, late night driver – offsetting the irritation from the loss of predictability of the Organic system during busy times.
Split, Cycle and Offset Optimization Technique (SCOOT) is better than nothing but too simple as ejj says. Combining it with traffic-responsive Urban Control (TUC) helps and if we add rural optimized light logic (ROLL) we get perfection:
SCOOT, TUC and ROLL.
Posted by: ToppaTom | 28 June 2009 at 11:36 AM
A lot of fuel can be saved with smart traffic lights, not everyone has a start/stop system. My small city puts out contracts every year for reprogramming intersections that go for more than $100,000. With smart lights, they reprogram themselves.
Posted by: SJC | 30 June 2009 at 09:41 AM
I think that a company call USA Signal Technology demonstrated this type of technology in Diamond Bar California. What ever happened to the project?
Posted by: George | 02 July 2009 at 05:21 PM