Green Algorithms
Civic Integrated Solutions recently installed and commissioned two smart traffic signal intersections along the new Edenderry Inner Relief Road, Co. Offaly. As part of our design process, our Traffic Signal Engineers incorporate the latest hardware and software to achieve the following:
Unhindered travel.
A pleasant, liberating urban environment is one free of gridlock, without unnecessary pollution from stationary vehicles, where traffic flows smoothly and noise is minimized.
Green light to allow freely flowing traffic.
No longer should cars, buses and bicycles need to stop for red at every intersection, instead their movement is governed by a system capable of handling any situation.
Both intersections have been designed to manage a high volume of traffic with emphasises on safety for Active Travel users. To achieve these results, Civic deployed the latest Cross Zlin RS 4S Traffic Signal Controller incorporating prolongation algorithms. This enabled our team to deliver on the client requirements which included the following:
For local and network adaptive control:
Stage on demand – defined stage or stages are activated only on demand of defined groups in the stage
Signal group on demand in seven priority levels - every single signal group can be activated only on demand. In case of demand collision is activated higher priority signal group
Complementary optimization of signal plan run - for signal group on demand can be defined set of complementary groups. In case of no demand on controlling group there is activated the highest priority complementary group
Immediate demands on signal group – for the highest priority signal group this functionality enables immediate activation of this group. It is widely used for public transport priority
Stage transition real time optimizing – every single stage or group transition is real time created based on safety parameters. It ensures as long as possible green time duration and as early as possible green time activation.
Green time optimizing based on detector data up to four prolongation steps – except of minimum green time should green signal reflect the real traffic demand. There are defined up to four prolongation periods based on critical parameters of traffic flow. Because traffic flow parameters are green time duration dependent is possible evaluate period independent way. Prolongation periods are at disposal for every single signal group and stage.
Prolongation based on various parameters of traffic flow – every prolongation period has defined simple or complex parameter of traffic flow for decision making process. There are used parameters as time gap, occupancy, occupancy rate, intensity, etc.
Easy creation complex prolonging and demanding conditions - For creating of complex parameters are at disposal useful wizards.
Enhanced detector failure logic – it is taken into account that detector is only technological device with possibility to be broken. There is implemented automatic algorithm for failure recognition based on historical data with possibility of manual fine tuning.
For network adaptive logic:
Green time redistribution – not used green time of one stage is offered to following stages even if is maximum defined green time exceeded. This algorithm is useful for following of traffic flow variations. This way is possible react on unexpected changes in traffic flow distribution and in the same time hold the green wave.
Beginning and terminating green time fixation to neighbors for green wave – for critical signal groups for coordination especially at critical nodes is possible to define oscillation points connected to cycle time or stage time to hold certain level of coordination.
Balancing internal cycle time to keep coordinated cycle – crucial algorithm for traffic actuated / adaptive green wave run. Controller internally work dynamic way (activates and omits stages or signal groups, prolongs green time) but for coordination has to follow united cycle time. This algorithm ensures this functionality.
Enhanced algorithms for reaching coordination – switch on or switch signal plan in arbitrary time. Controller itself checks for coordination and choose the fastest way how to reach it.
For public transport and priority vehicle preemption:
Multilevel prioritizing of vehicles – advanced conflict and priority management in case of more priority demands in one time.
Individual vehicle detection – every single demand received to controller contains vehicle information. It could be taken into account the individual vehicle characteristics.
Both way interactions –receiving commands to controller is not enough. Also informing Public Transport driver about reaction on demand is useful. Big help is priority green time display. It says to driver now you can go and now you are prioritized.
Delay management – conditional preference takes into account delay is preferred by customers thanks to better impact to individual transport
Civic Integrated Solutions were contracted to to supply, install and commission two traffic signal intersections and all associated public lighting along the new inner relief road which included Passive Safe Lighting Columns, LED Traffic Signals and LED Street Lights. Our engineering and contract management teams were responsible for implementing the overall design from Factory Acceptance Test (FAT), Site Acceptance Test (SAT) to Electrical Safety Test and Verification to Safe electric Standards.
