Clean environment through green technology

TRANSPORTATION SYSTEMS MANAGEMENT IN AN INDIAN CONTEXT

ByP. S. SURESH1 & C. KRISHNA KUMAR2

ABSTRACT

Proliferation of vehicles in the roads coupled with the non commensurate expansion of road capacity have resulted in traffic congestion and increased pollution levels in most of the roads in cities across the world and cities of India are no exception to this. It is estimated that a higher percentage of harmful emissions are caused by road transport alone and a major chunk of these emissions are caused by stopping and starting of vehicles at intersections. Increasing the capacity of the existing road network alone cannot be seen as a panacea of ever increasing congestion on roads. It is here the necessity of transportation systems management is coming into prominence. It can be seen that automobile emissions, which causes disastrous side effects on environment can be reduced to a great extent by using various transportation system management measures. Transportation systems management is the application of transportation engineering, planning and traffic control techniques, within a defined policy framework, to the road network in a given area or over an extended length of road, to achieve a specific set of community objectives. This covers the traffic management measures like installation of traffic signals with advanced controllers, area traffic control systems etc. along with other transportation system management measures like transit management including public transport priority, demand management measures like car pooling, restraint measures like congestion pricing in the central business districts etc. This paper details various transportation systems management measures and explains further, relevance of these measures in an Indian context. The effectiveness of these transportation system management measures with emphasis on traffic control are discussed in this paper. Traffic control appurtenances like LED based signal aspects, solar based signals etc. and its energy saving capabilities are further discussed in this paper. Energy savings accrued from the installation of these appurtenances in an Indian city are also detailed in this paper.

1.Introduction

Transportation systems are built to serve people in undertaking their economic, social and cultural activities. Demand for the use of transportation facilities has been higher than the capacity of the systems in cities for a long time. Traffic congestion and related impacts of it like environmental degradation, wastage of fuel etc. are on the rise in most of the cities across the world as an after effect of increased mobility. Proliferation of vehicles in the roads coupled with the non commensurate expansion of road capacity have resulted in traffic congestion and increased pollution levels in most of the roads in cities across the world and cities of India are no exception to this. It is estimated that a higher percentage of harmful emissions are caused by road transport alone and a major chunk of these emissions are caused by stopping and starting of vehicles at intersections. Increasing the capacity of the existing road network alone cannot be seen as a panacea of ever increasing congestion on roads. It is here the necessity of transportation systems management is coming into prominence. It can be seen that automobile emissions, which causes disastrous side effects on environment can be reduced to a great extent by using various transportation system management measures. Transportation systems management (TSM) is the application of

1 Manager- T.E., CMS Traffic Systems Ltd., W 324, M.I.D.C., Rabale, Navi Mumbai.400701. e mail pssuresh@cms.co.in

2 General Manager, CMS Traffic Systems Ltd., W 324, M.I.D.C., Rabale, Navi Mumbai.400701. e mail ckrishnakumar@cms.co.in

transportation engineering, planning and traffic control techniques, within a defined policy framework, to the road network in a given area or over an extended length of road, to achieve a specific set of community objectives. This covers the traffic management measures like installation of traffic signals with advanced controllers, area traffic control systems etc. along with other transportation system management measures like transit management including public transport priority, demand management measures like car pooling, restraint measures like congestion pricing in the central business districts etc. Transportation system management for city road transport is detailed in this paper. TSM integrates short term transportation elements with emphasis on low or moderate cost. Various transportation system management measures are detailed in this paper. These measures are effective in augmenting the capacity and help in reducing the ill effects of traffic congestion. Traffic control measures are an important element of TSM. Effectiveness of traffic control measures including advanced ones like area traffic control systems in reducing the environmental degradation are discussed. Energy saving capabilities of some traffic control appurtenances are detailed further in this paper.

2. Transportation systems management

ITE (1981) describes TSM as a planning and operating process designed to conserve resources and energy and to improve the quality of urban life. All existing transportation facilities are viewed as elements of single system; the objective is to organize these individual elements into one efficient , productive and integrated transportation system. And it further state that TSM is an important component of a comprehensive transportation plan. It should be considered before embarking on capital intensive set of operations. Different classes of TSM actions are detailed in Table 1.

TABLE 1. TSM ACTIONS

Class Strategy group ActionsTraffic management Traffic operations Intersections and roadway

wideningAimed at improving vehicle movements by increasing the capacity and safety of the existing facilities and systems

One way streetsTurn lane installationTurning movement and land use restrictions

Traffic control Local intersection signal improvementArterial signal systemArea signal systemExpressway diversion and advisory signingExpressway surveillance and control

Roadway assignment Exclusive bus lane-arterialTake- a laneAdd- a -laneBus-only streetContra flow bus laneReversible lane systemsExpressway HOV bypassExclusive HOV laneTake- a laneAdd- a –lane

Pedestrian and bicycle Widen sidewalkPedestrian grade separationBike ways

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Bike storagePedestrian control barriers

Transit management Transit operations

Simplified fare collection

Bus route and schedule modification

Transit managementInter modal Coordination

Express bus serviceBus traffic signal pre emptionBus terminals

Marketing programmeMaintenance improvementsVehicle fleet improvementsOperations monitoring programmePark and ride facilitiesTransfer improvements

Demand management Para transit Carpool matching programmesOriented towards reducing trips or number of vehicles by encouraging other types of transportation services

Van pool programmesTaxi/group riding programmesDial- a-rideElderly and handicapped service

Work Schedule Staggered work hours and flexible work hours

Restraint measures Parking management Kerb parking restrictionsThese measures are aimed at discouraging vehicle use mostly through restrictive controls

Residential parking controlOff- street parking restrictionsHOV preferential parkingParking rate charges

Restricted Areas Area licensingAuto restricted zonesPedestrian mallsResidential traffic control

Commercial vehicle On street loading zonesOff street loading zonesPeak hour on street loading prohibitionTruck route system

Pricing Peak hour tollsLow occupancy vehicle tollsPetrol taxPeak/off peak transit faresElderly and handicapped faresReduced transit fares

Use of these TSM measures were of limited nature in most of the cities of India. Measures like public transport priority have started in limited stretches in cities like Mumbai. Parking management measures are implemented in some limited areas. Heavy vehicles are banned within city limits during peak hours. However most of the cities in India are in need of a well co- ordinated TSM action plan to effectively manage the burgeoning traffic. Many roads in cities are not having adequate pedestrian facilities and it appears that footpaths and subways are the most neglected areas. Indian cities are beset with the problem of heterogeneous traffic. However, even a simplest measure like segregating the traffic on the basis of speed has not been enforced in most of the Indian cities. Measures like Congestion pricing as implemented in cities like London and Singapore are yet to be implemented in Indian cities.

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3. Traffic control measures

Traffic control consists of use of signs, signal and road markings. Effective use of these can result in savings of energy. In the case of signalized intersections , number of measures can be taken so that fuel wastage to vehicles in the road network are reduced. These include,

1. Traffic responsive signal time plans2. Coordination of signals in arterial roads3. Vehicle actuated signals4. Area traffic control systems

3.1 Traffic responsive signal time plansNormally in the cities, traffic movements are repetitive. Traffic volume in peak hours and non peak hours are measures and according to this optimum signal time plans are generated and implemented. Softwares like Traffic Network Study Tool (TRANSYT) are used for this purpose. Optimised signal plans can result in reduced delay and number of stops to vehicles, which in turn reduce the fuel consumption of vehicles.

3.2 Coordination of signals in arterial roadsTraffic signals along an arterial road can be co- ordinated so that traffic movement along the arterial road is given preferential treatment. In this method vehicles along arterial roads have to face minimum delay and number of stops. In peak traffic hours, the vehicle movement through the arterial roads being heavy, this method can result in fuel saving of vehicles.Traffic signals in an important arterial road in Pune, having a length of approximately 5 km was co-ordinated by using optimised signal plans generated by TRANSYT. Benefits of signal co-ordination in Pune Satara road as found by TRANSYT simulation run are listed in Table 2.

TABLE 2 BENEFITS OF SIGNAL COORDINATION IN PUNE SATARA ROAD

Particulars Fuel consumption in litres/hr.(Before coordination)

Fuel consumption in litres/hr.(After coordination)

Savings of fuel (in litres/hr.)

Morning peak 404.0 385.4 18.6Evening peak 410.9 390.9 20.0Off peak 400.2 383.5 16.7

It was found that the annual fuel savings due to this signal co- ordination works out to be 52,790 litres amounting to Rs. 1.8 million as per December 2003 average fuel prices.

3.3 Vehicle actuated signalsIn this case, signal phases are controlled by detector actuations. This can be fully actuated or semi actuated. In the case of semi actuated signals, a designated street will have green at all times until detector on the side street detect vehicles on minor streets. The signal then provides green to the minor street traffic after an appropriate change interval. In the case of fully actuated signals, all signal phases are controlled by detector actuations. Minimum and maximum green time are specified for each phase. Cycle lengths and green times vary considerably in response to the traffic demand. Certain phases in the cycle may be optional and may be skipped entirely if detectors sense no demand. 3.4 Area Traffic control systems (ATC)In area traffic control systems, number of signals are controlled from one centralized location. This can be fixed plans by time of day, traffic responsive or real time (dynamic) ATC. In fixed type ATC signal plans are generated as per traffic volume measurements and these are implemented according to the time of day. In traffic responsive ATC, traffic flow are measured and are compared with a library of traffic flows and time plans in the central computer system. Suitable time plans are selected according to the traffic flow and implemented in signals.

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In the case of real time ATC, traffic flow is measures by detectors. Optimised signal plans are generated in the centralized computer with the help of in built traffic models. The optimised plans are sent back to the controllers at junctions and implemented. Real time ATC is capable of adjusting the signal time plans according to the variations in traffic flow. It was found that implementation of real time ATC has resulted in reduction of delay and increase in travel speed for the vehicles in the network. Benefits of real time ATC in Delhi are detailed in Table 2. It can be seen from the table that there is a reduction in delay of 21.7 % in the ATC area. The travel speed has increased to 22.86 Km/h in spite of an increase in number of vehicles using the network.

TABLE 2: BENEFITS OF ATC IN DELHI

Parameter Before study After Study DifferencePercentag

e

Delay per km (sec) 50.8 39.7 -11.0 - 21.7

Journey Time per km (sec) 165.6 157.5 - 8.1 - 4.9

Average Speed in ATC area

(km/h)21.74 22.86 1.12 5.2

Veh-km per hour in the ATC area

over 31 months107,191 133,734 26,543 24.8

4. Energy saving traffic control appurtenances

4.1. LED retrofit traffic signals

Incandescent bulbs are being used as light sources in traffic signal heads for a long time now. Light Emitting Diodes (LED) have been used in place of incandescent lamps in traffic signals of late due to its energy efficiency and longevity. In the city of Surat, signal aspects were replaced with Light Emitting Diodes (LED) in place of incandescent bulbs in majority of intersections

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Figure 1 LED signal face

4.1.1 Cost savings

268 red signal faces, 391 amber signal faces and 522 green signal faces were replaced with LED signals. In addition to this Pedestrian signal faces of 187 numbers each of red and green were also retrofitted with LED signals. Considering 60%, 35% and 5 % as the usage time of red , green and amber signal faces respectively , annual savings were calculated as shown in Table 3. Initially, the incandescent lamps were having wattage of 100 each and the same was reduced to 10 for red and amber, 4 for green and 3 for pedestrian green and pedestrian red.

TABLE 3 ENERGY SAVINGS PER YEAR

Signal faces NumberWattage -Incandescent

Wattage LED

Initial wattage

(kwhr.)

After LED installation.(kwhr.)

Savings/yr(kwhr.)

Red 268 100 10 127166 12717 114449Amber 391 100 10 7136 714 6422Green 522 100 4 66686 2667 64018

Pedestrian Red 187 100 3 92144 2764 89380 Pedestrian Green 187 100 3 23889 717 23173

Blinkers 123 100 10 53874 5387 48487Total 370895 24966 345929

Figure 2 shows the possible savings for different signal faces as per the variation of unit cost of electricity for 25 junctions.

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500000

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1500000

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1 2 3 4 5Cost of electricity (Rs/kwhr.)

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Red Amber Green Pedestrian red Pedestrian green Blinkers Total

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Figure 2 Annual savings for 25 junctions.

4.1.2 Possible savings

Possible savings were calculated on the basis of the details available from the study in Surat. It was found that 17 % of signal faces are red, 23 % Amber, 31% green, 11 % each pedestrian red and pedestrian green and 7 % blinkers. These figures were used for estimating the annual savings for different number of intersections. Possible savings with an electricity charge of Rs 3/kw.hr. for different number of intersections are shown in Figure 3

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2000000

4000000

6000000

8000000

10000000

12000000

14000000

50 100 150 200 250 300 350 400 450 500 550 600

Number of junctions

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Red Amber Green Pedestrian red Pedestrian green Blinkers Total

Figure 3 Possible savings for signalised different intersection groups at Rs 3/kwhr

It can be seen from figure 3 that there can be a savings of Rs. 9.5 million, at an electricity rate of Rs 3 /kwhr, for a city having 500 signalised intersections if retrofitting with LED is done Over the past few years the use of LED retrofitting in traffic signals is growing phenomenally due to its energy efficiency and durability. By taking into account technology explosion taking place in the development of LED, it is expected that their efficiency will double in every two years and due to this the number of LED in a signal can be brought down without affecting the intensity of light output It was found that the power savings due to LED is 88 % and the savings in maintenance cost is 51 %. It is estimated that in a city having 500 intersections approximately Rs. 9.5 million can be saved per annum, at a rate of Rs. 3/ kw. hr. of electricity, by completely retrofitting signals with LED aspectsIn addition to this, use of appurtenances like solar based signals have resulted in energy savings. These are suitable in areas having erratic power supply. The cost effectiveness of this depends on the storage capacity of back up battery.

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5. Conclusion

Various transportation systems management measures have been detailed in this paper. These include traffic management measures like installation of traffic signals with advanced controllers capable of co-ordinating signals, area traffic control systems etc. along with other transportation system management measures like transit management including public transport priority, demand management measures like car pooling, restraint measures like congestion pricing in the central business districts etc. TSM measures in Indian cities are far from adequate. A well co-ordinated TSM action plan is needed in Indian cities to mange the burgeoning traffic . Traffic control measures like co-ordination of signals, area traffic control system etc. can result in fuel savings and reduction in delay . It was found that Co-ordination of signals in a 5 km arterial road in Pune has resulted in an annul fuel saving amounting to Rs.1.8 million. The implementation of ATC in Delhi has resulted in reduction in delay and increased travel speed to the vehicles traveling through the network in spite of the increase in traffic. Appropriately designed traffic control appurtenances can also yield energy savings. Use of LED based signal faces has resulted in energy savings in the city of Surat.

References

1. Mayinger, Franz (Editor), (2001) “Mobility and traffic in the 21st century” Springer-Verlag Berlin2. Mc Shane, W. R. and Roess, R.P.(1990) “Traffic Engineering” Prentice Hall, New Jersey3. ITE (1981) “Planning urban arterials and Freeway systems: Proposed Recommended Practice, ITE

Journal , February.4. Technology Information, Forecasting and assessment council (TIFAC) (1996) “Road Transportation

Technology vision 2020” Department of science and Technology, Government of India. New Delhi.

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