Area traffic control system Improving Traffic in the island city

Fully commissioned in August 2011, the Mumbai ATC project has transformed the conventional signaling system on the City roads into a real-time computer controlled one. The project won the award for the Best ITS system implemented in 2011 from the Government of India. TrafficInfraTech gives the details.

Mumbai Urban Transport Project (MUTP), the multi modal project taken up by Mumbai Metropolitan Region Development Authority (MMRDA), aims to bring about improvement in current traffic and transportation situation in the MMR (Mumbai Metropolitan Region) with the financial assistance of the World Bank. MUTP envisages investment in suburban railway projects, local bus transport, new roads, bridges, pedestrian subways and traffic management activities. A major component of the project is the introduction of an Area Traffic Control (ATC) System in the island city of Mumbai which is implemented by the Municipal Corporation of Greater Mumbai (MCGM).

Mumbai ATC Project has a long history dating back to 1995 when the MMRDA took up the feasibility study of the implementation of a traffic responsive system for the island city. The work was awarded to M/s Pell Frischmann Consultants of United Kingdom. As part of the study, a pilot project to check the effectiveness of the vehicle detection was carried out by the consultants. Detector trials were conducted with the help of Traffic Police, using the equipment of various leading players in the industry in the adaptive traffic market. The results were very positive and based on the recommendation, it was decided to take up the implementation of the project.

The nod from the World Bank came around the year 2000 and the project finally went to the bid on 2003. As per the World Bank guidelines, all fully adaptive ATC systems which have been working on other cities were eligible to be selected for the implementation here. Based on an international competitive bid, the joint venture of M/s Telvent Trafico y Transporte (Spain) and M/s CMS Computers Ltd (India) was awarded the work in 2007. The project was divided into two phases – Phase I (Milestone 1) comprising the pilot 53 junctions extending over an area between Haji Ali, Marine Drive & Regal Cinema and Phase II comprising a further 200 signals in the island city, eastern and western suburbs.

The Project Components

ATC, as is known, is a system of centrally coordinating traffic signals using real-time data collected through detectors. This is an advanced tool in traffic management for efficient urban road network utilisation.

The components of the system procured for Mumbai:

• Fully Adaptive ATC System which is a software in the control centre. The system which won the bid was ITACA (Intelligent Traffic Adaptive Control Area), developed and marketed by the Spanish company, Telvent Trafico y Transporte – now owned by Schneider Electric of France.
• As the street furniture was old, it was decided to replace all poles and signal aspects along with the signal controllers.
• Vehicle Detectors.
• Leased Data Communication network from MTNL.
• Central Control Room at Traffic Police Head Quarters and Information Centre at MCGM Offices.
• Civil Works including development of a fully ducted network which is expected to ease the maintenance process.

The implementation of the ATC system consisted of a number of stages – design, construction, supply and installation of equipment, system start-up, testing, training, and system maintenance. There were specific lessons learned in each of these stages. Whilst certain preventive measures were already in place, other techniques/ methodologies needed to be developed and included in the overall implementation experience.

Features of the System

The traffic controllers are capable of checking the detection data in every 0.01 second and transmitting it to the control centre every five seconds. The system stores the data at five minute intervals for every detector along with calculation of flow, occupancy time and load.

The area can be divided into sub areas of junctions with similar traffic behaviour. There can be unlimited number of sub-areas and they can be merged or further sub-divided as per the requirements. The basic three parameters of cycle time, green splits and offsets are optimised automatically by the system to minimise the stops and delays. The system, however, may not take short duration traffic surges as the calculations average out traffic over three cycles in order to avoid drastic changes in the pattern which may create confusion to the users.

The success of any system will depend upon the level of calibration that is carried out. The conditions in Mumbai required extensive calibration of the lane capacities, mix of traffic and driving behaviour. Pell Frischmann Consultants, the engineers for the project, got directly involved in it through the contractor to help achieve the same faster and effective.

Innovations introduced

The implementation of an ATC system of this size is done for the first time in India. The procurement specifications ensured that state-of-the-art technologies and equipment were brought into the city.

Signal Controllers: The controllers procured facilities for handling bus priority and emergency services in addition to the requirements of the ATC system. Over and above these, the following features were also incorporated:

Red Lamp monitoring: This is an in-built safety measure by which the controller will generate alerts for the loss of lamps, especially the red lamps. If more than one red lamps are lost on a particular approach, the signal will automatically go to flash mode. This ensures safety of the road users as there could be confusion to the drivers if the red lamps are not visible or lost.

Night Time Dimming: The new signal aspects are very bright for better visibility during the day time. However, at night, the controllers can automatically dim the lights which reduce the energy consumption.

Overhead Video Detectors: Though initially the project was implemented with the inductive loops, the same was changed to overhead detectors using video technology. Accordingly, nearly 800 camera detectors are being used in the city. Supplied by Belgium based Traficon N V, the detectors are flexible as one camera can manage four traffic lanes and the detection area can be modified based on the site requirements – a definite advantage in Mumbai where three lanes handle almost four lanes of moving traffic. These cameras are very small in size and are located 7 to 10m above ground and as a result, are not prone to damages like the loops. The last batches of the cameras (about 500 nos.) are capable of mpeg-4 video streaming as well.

Single Source LED aspects: Mumbai has been using arrays of LED lights for traffic signals for some time now. However, the damaged LEDs in the array present an unpleasant sight to the road users. As part of this project, single source LEDs (which have 6 or 7 LEDs only) were used. The lower number of LEDs used per aspect has reduced the total power consumption which is a direct saving to the city.

Signal Poles: Signal poles were made of galvanised iron with PU coating which is resistant to rust without the need of regular paintings. The termination of the wires is provided at the top of the pole (located within the pole) which has eliminated the vandalism of the signal system – one of the most common problems in the city.

The cantilever poles were designed in a sleek manner which will not become a visual obstruction on the street even while being extended to the middle lanes of the traffic. The visibility of the signals is one of the most talked about points by the road users. Also, the cantilevers are designed in such a way that when the Ganesh procession (during Ganesh Chaturthhi) or any such activity takes place, they can be swung off the traffic lanes facilitating unrestricted movement.

Pedestrian Push Buttons: In order to introduce demand based pedestrian stage at some of the intersections, pedestrian push buttons are introduced. This was introduced with the audible signals too for everyone’s use.

Fully ducted Network: This was done on the recommendation of the Consultants to avoid frequent digging which happens for many other utilities in the city.