ATCS for effective signaling cycle

Though we had a couple of installations in some metros, ATCS still can be considered as a new approach for Indian traffic management. Although adaptive traffic control systems are being used worldwide since many decades for the effective utilization of road space, their implementations in non-lane based mixed traffic flow conditions still poses greater challenges. The model based systems developed in developed countries generally are calibration intensive. Hence there is an urgent need to educate and empower local community on the technology and solutions available. Ideally the ATCS for Indian cities shall handle non-lane based mixed traffic flow conditions and self-calibrating for Phase lengths and Cycle lengths. Local expertise is also required to be developed for designing, configuring and calibrating the ATCS for our roads. Another major feature of ATCS, but most of the time not discussed, is the decision support capacity of the system.

In an adaptive signal control environment all traffic junctions are networked to a central server for collecting real-time traffic data for processing and proposing optimum signal time to traffic signal controllers based on the real-time traffic flow. It means the entire traffic scenario of a city is captured by the ATCS application running on the central server every second. This traffic data can be made available for simulation, analysis, planning and monitoring. Unfortunately, none of the RFPs published in recent past for the ATCS has not emphasized on this aspect. Many of the time the RFPs miss publishing the functional requirements too. Another important aspect to be considered while selecting the technology for our roads is the compliance for standards and assured long term product support through local vendors.

Sonal Ahuja,
Regional Director, Middle East,
PTV Mena Region DMCC

The Indian traffic poses a major problem for many well-established ATC systems: The big percentage of two- and three-wheelers and the non-lane-based driving behavior make the correct detection of traffic demand with conventional loop or video sensors very difficult if not impossible. For that reason, we chose to follow a two-fold approach to target the Indian market:

a. Use video sensors that are specifically tuned
to non-lane-based traffic, and

b. Test and enhance our adaptive control algorithms in our microsimulation tool PTV Vissim, that is well-known and very well adjusted to Indian driving conditions.

Only after we saw in several simulation studies that our approach is very well able to decrease the travel times and stops in the system significantly, we put our ATCS on ground for a pilot in India’s greatest planned city – Chandigarh, using PTV Epics and PTV Balance. For this project three signalized intersections were considered and the existing signal control systems were integrated with the new system by the local control of PTV Epics which is continually optimizing traffic lights with respect to traffic demands. All the three signalized junctions were synchronized by PTV Balance, which keeps the city’s rhythm flowing.

Unlike a fixed time control system which always runs its program in the same way regardless of the actual traffic situation, trafficadaptive control reacts to what’s happening on the roads and can efficiently utilize the capacity of the nodes. And the results of Chandigarh proved that Adaptive Traffic Control Systems can be successfully implemented in all the congested cities, since it results in short delays, moderate travel times, fewer emissions, reduced noise and keeps the city’s traffic moving.

We have two products for the Adaptive Traffic Control System: PTV EPICS (Entire Priority Intersection Control System) and PTV BALANCE (Balance Adaptive Network Control)

Features of PTV EPICS:

• PTV Epics is the perfect traffic-adaptive control instrument.

• It was developed specially for single nodes and runs directly inside the control unit.

• The model-based process observes local conditions and calculates numerous control options every second. PTV Epics then uses its internal model to evaluate the different control options before applying the best one. In this process, it takes all modes of transport into account – from individual motorized transport and pedestrians to prioritizing public transport.

• It continually optimizes switching for traffic lights at individual nodes, reduces planning and data transmission costs. This saves you time and stops road users from waiting unnecessarily at red lights.

• PTV Epics also allows the integration of public transport prioritization.

• In operation, PTV Epics accesses the camera data for the node, uses it to recognize the incoming vehicle flows, and adjusts its simulation model for calculating the effects of different control options based on this. In less than a single second, PTV Epics optimizes the phase sequence and its timings by optimizing the total performance index. In this way, for example, a bus will receive priority at the intersection if public transport is prioritized by being assigned a high weighting. PTV Epics stands out in particular by being very intuitive and quick to implement compared to traditional rule-based control systems.