A Status of Energy Efficient Led Based Traffic Lamps in Istanbul Case Study  Yusuf Dursun, R&D Traffic Systems Director  Moayed Almobaied, PhD Cand. R&D Specialist  Burcu Buyukkinaci, PhD Cand. R&D Engineer June , Málaga R&D Department at ISBAK Inc., Istanbul Municipality Istanbul Telecommunication Transportation and Security Technologies

June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 2 Introduction Contributions of LED Based Traffic Lamps to Energy Saving Other Properties for LED Based Traffic Lamps Disadvantages of LED Based Traffic Lamps Conclusion LED Based Traffic Lights & Incandescent bulbs

Introduction June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 3  Population: ~15 million (2016). Population  Daily usage of transportation : ~11,5 million  Area: 5343 km². Area  Total registered vehicles : ~ 3,25 Million.  Traffic signal modules : traffic signal modules in 2101 signalized intersections (February 2016).

Introduction  Recently, the global energy shortages have been rapidly increased.  The global energy demand is set to grow by 37% by 2040 as the International Energy Agency (IEA) mentioned in world energy outlook  Conventional traffic lights contain bulky and powerful lamps where these lamps consume a lot of amount of electrical power.  In big cities, with many thousands of such traffic light units, developing more efficient solutions to reduce the amount of consumed energy is still an active research topic.  In order to save energy, cities switched the conventional bulbs in traffic lights to LED based traffic lamps. June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 4

Introduction  LED is a solid state optoelectronic semiconductor which converts most of the input electrical power directly to light.  In 1907 The Englishman Henry Joseph Round discovered that inorganic materials can light up when an electric current is applied.  At 1994 in Japan, the bluish-green LED was produced and the traffic applications, which based on LED technology, have been established in  In 1998, the research and development department at ISBAK started to follow this new technology in the designing process of the traffic lamps. June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 5

Introduction From Literature:  The City of Portland 2001: has replaced all incandescent traffic light bulbs with LED modules, which save approximately 4.9 million kilowatt-hours per year. LED modules represent an 80% percent reduction in energy consumption over standard light bulbs. The replacement to LED lights saves the city of Portland $ annually in signal power costs. These savings are equivalent to powering over 350 Portland homes each year, and led to annual CO2 emissions reductions of some 2880 tons. reducing transportation maintenance costs by $ a year in off-hour call-out costs and replacement bulbs June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 6

Introduction  In Chicago, USA, a city run project retrofitting and installing LED energy efficient lighting in all of the cities traffic lights at 2900 intersections, started in The LED conversion project is said to be reduced energy use in Chicago for traffic lights by 85%. As a result the city is saving 2.55$ million annually in energy savings and 100,000$ annually in materials. It is also reducing CO2 tones annually.  ISBAK successfully developed and produced mm diameter LED based traffic lamps within a TEYDEB (Technology and Innovation Funding Programs Directorate) Project in June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 7

Introduction June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 8  European standard for Traffic Control Equipment Signal Heads EN 12368:2000  Turkish Standards Institute (TSE) published the Traffic Control Equipment Signal Lamps Standard TS EN  In this case study, the contributions of traffic signal modules in 2101 signalized intersections in Istanbul to the national economy, energy saving and environmental protection are analyzed.

LED Based Traffic Lights & Incandescent bulbs June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 9

LED Based Traffic Lights & Incandescent bulbs June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 10  Conventional incandescent lamps require color filters to provide the desired color of light.  In contrast, LED based traffic lamps can be designed to directly produce light as the required color.  In AlInGaP LEDs, operating 10,000 hours under 30mA current value leads to approximately 20% reduction of starting luminous flux. After operating hours there will be approximately 25% reduction of luminous flux.  On the other hand, the luminous flux of incandescent traffic bulbs, which have a life time of 8-10 thousand hours, reduces to the half of the starting value after only 1500 hours of operating.

Contributions of LED Based Traffic Lamps to Energy Saving June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 11  Average operating times for traffic lamps of the intersections in Istanbul.

Contributions of LED Based Traffic Lamps to Energy Saving June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 12  Energy consumption of incandescent bulbs previously used in Istanbul.

Contributions of LED Based Traffic Lamps to Energy Saving June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 13  Energy consumption of LEDs based Traffic lamps in Istanbul.

Contributions of LED Based Traffic Lamps to Energy Saving June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 14  Annual energy savings with LEDs based Traffic lamps in Istanbul  The total annual Energy Savings is about 89%. Hence, approximately two million dollars of annual energy savings were achieved by switching all incandescent traffic bulbs in Istanbul to LED based traffic lamps.  The maintenance costs reduce by 91% with LED based traffic lamps due to the statistics result which show that just only 5% of LED based lamps are broken down once a year.  On the other hand, the incandescent lamps are changed due to breaking or due to the loss of luminous flux in every 6 months for overhead traffic lamps.  When only the energy costs are considered, the amortization period is 2.2 years for an LED based lamps. However, this period will reduce to be 1.5 years in case of the maintenance costs are supplemented.

Other Properties for LED Based Traffic Lamps June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 15  In addition to the energy saving property as a main contribution of using LED based lamps instead of old style Incandescent bulbs in Istanbul, there are some other contributions related to road safety and environmental protection.  Contributions of LED based Traffic Lights to Traffic and Road Safety  Contribution of LED Based Traffic Lights to the Environmental Protection

Other Properties for LED Based Traffic Lamps June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 16  Contributions of LED based Traffic Lights to Traffic and Road Safety.  Drivers can effectively distinguish the saturated color LED based light in comparing to the other light sources under the bright sunlight.  LED based lamp has the best light source which can be seen by the drivers in adverse weather conditions and can easily recognize other distracting light sources on the opposite road lane.  Reflectors and colored lenses are used in the signal units with conventional signal lamps.  The sunrays come with horizontal angles especially in the morning and evening rush-hours; hence, drivers cannot easily perceive the color of the traffic light due to the reflections from the reflector of the traffic lights.  This advantages of LED based traffic lights will decrease the numbers of accidents in the cities.  Conventional traffic lights emits light along a horizontal axis but in fact only a portion of the light can be seen by the drivers and pedestrians. The majority of the light beam above horizontal axis would have been wasted.

Other Properties for LED Based Traffic Lamps June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 17  Contribution of LED Based Traffic Lights to the Environmental Protection  Transportation is the spearhead with 36% CO2 emissions today.  LED based traffic lights can be considered to be environmental solutions for their energy saving potential.  According to statistics of International Energy Agency (IES) in 2013, grams of CO2 emissions are released to produce 1kWh electric energy in Turkey.  For comparison, when the most frequently used automobiles in Turkey are taken into consideration, an average automobile releases 2725 kg CO2 when it travels averagely km per year. Which means green- house gas emissions would be prevented equivalent to 3139 automobiles withdrawn from traffic.  8555 tons/year of CO2 emissions are prevented by million kilowatt-hours energy savings.

Disadvantages of LED Based Traffic Lamps June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 18  LED Based Traffic Lamps are more expensive than conventional lighting source technologies due to their initial cost.  Historically, payback time was 3, 3.5 years due to the leakages in technology at the early LED based traffic lamps at Nowadays, the payback time for the LED based traffic lamps is reduced to 1.5 years.  In areas with heavy snow conditions, an other disadvantage for the LED based lamps is appeared; Since LEDs produce a very little amount of heat which is not enough to melt the snow accumulated on lamps outer lens.  Electronics expertise is required to design electronic drivers in order to supply the correct polarity, voltage and current at a constant flow.

Conclusion June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 19  Usage of LED based signal lamps is rapidly increasing all over the world due to the noticeable increase in the light efficiency of LEDs, energy-saving, ease of maintenance, their long life times and other benefits.  Installation costs of LEDs are higher than incandescent lamps; however, the energy consumption is decreased by 89%, the maintenance costs are decreased by 91% and the pay-back time for the LED based traffic lamps is about 1.5 years.  In this case study, The research and development department (R&D) at ISBAK Inc. demonstrates the benefits of switching the old-style incandescent bulbs to the LED based lamps in traffic signalization system at Istanbul.  Contribution of total traffic signal modules in 2101 signalized intersections in Istanbul to the national economy is explained.  Approximately two million dollars of annual energy savings were achieved by switching all incandescent traffic bulbs in Istanbul to LEDs based traffic lamps and 8555 tons/year of CO2 emissions are prevented by million kilowatt-hours per year.  In Turkey, which has approximately 9,000 intersections, if all traffic signal lights are switched to LED based lamps systems then it is clear that significant energy savings, environmental protection and the maximum safety in traffic will be provided.

Conclusion June , Málaga R&D Department at ISBAK Inc., Istanbul Metropolitan Municipality 20 As a future work:  we will constraint on the low voltage systems (< 42 VAC) for traffic light which provide an important feature of traffic signaling due to the better monitoring and the increased safety for the engineers working on the traffic signals at the street.  Power LED Technique.

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