The success of SCATS in Asia is an indication of it being adaptable to heterogeneous traffic conditions – that is different types of vehicles moving in a non-lane pattern. Two possible reasons for this could be:
Stop-line detection method adopted in which traffic volumes are measured at the stop-line of the signal.
Negative feedback principle – A method where the output of a process is fed back as input for accurate output in the next cycle. The repetitive process of negative feedback makes the system a self-learning solution.
An important issue in India is the communication network being available intermittently. In the event of a failure of communications between junctions or central computer, the local controllers (at each junction) can revert to a form a time-based coordination known as Flexilink. In this mode, adjacent signals are synchronised by a clock or power mains frequency. Local vehicle actuations can also be active in this mode, Flexi-link is the usual fallback mode of operation.
One of the other questions to be asked is – how will an emergency vehicle get through to its destination quickly? VIP movement in cities also need to be quick and cause minimum inconvenience to other commuters.
SCATS has a matured emergency management system, where in a predetermined path can be uploaded for emergency vehicles by a user. Route pre-emption as it is known allows a user to manage the sequential introduction of a green window through a set of instructions. This is done by an operator sitting in the control center. Route preemption could significantly reduce the number of traffic controlling personnel required at the junctions.
SCATS responds to pedestrian push button calls and dynamic pedestrian movements. It also implicitly tracks pedestrian calls over time and attempts to consider the effect these movements have on the road network within the traffic signal optimization process.
Some points for the success of ATCS systems in India:
Most cities in India aim for an integrated command and control center, an integration of all sub-systems. ATCS systems are to provide an interface to export data to other systems for developing specific applications or intelligence to meet various needs of the authorities or end-users.
Learning from the past, for any adaptive traffic system to be successful, it is important for trained engineers to be deeply involved in deploying the systems. Calibration of the system to suit the traffic conditions of the city in the implementation phase is a critical success factor, local presence and expertise should be considered.
The effectiveness of a system is usually evaluated by end-users themselves or in collaboration with an academic institute. ATCS systems that are independently evaluated over decades are to have shown benefits in reduction of stops and delays and thereby cutting down travel time are to be chosen. Other important direct benefits include reduction in fuel consumption and better air quality through reduced emissions.
For any rapidly developing country, Government-Industry-Academia collaboration plays an important role in adopting proven and sustainable solutions for a better living.
Finally, effective use of a road could be achieved by employing the 3E principle. Engineering, Enforcement and Education. ATCS, help improve the efficiency of signaling systems in the city and provides data for effective engineering (civil works) of road network. Different technologies are being used to bring in traffic-discipline by penalising violators. Education is an area which has a great scope for improvement.