Semafori LED 00LED lights are being present in Bosnia and Herzegovina for last several years but for traffic lights and signals conventional bulbs are still used. The State of Oregon in the United States has implemented a project of replacement the old bulbs in traffic light signals in 1993 but we still think LED technology is the new one.

How can't we see all the benefits of the new technologies and why are we afraid of investing to make a profit? LED technology has no disadvantages but we have it present in our traffic lights just now. The most important advantage of the LED lighting is the increased visibility. Conventional bulbs are usually covered with color filters or reflective lens which increases the amount of light that reaches the observer. LEDs do not require additional filters.

Traffic lights operate for 24 hours 365 days a year. Therefore, they have very important and useful function so they should be operating reliably. Large cities that require a lot of traffic light signals have costs in millions only for electrical energy. In addition there are also the maintenance costs.

semafori London
First traffic signal light from
1868 year installed in front
of the Houses Parliament
in Britain (www.planeta.org.rs)

High investment costs are usually compensated with low maintenance costs and long service life that can be up to 10 years. LEDs are used in varying light signs and its advantages in the first place are good visibility and current sign change (Krvar, 2009.3-4).

LED traffic signs are not the novelty in the world but in Bosnian streets the number one are still the conventional bulbs. In 2012 the authorities in Tuzla implemented the project of replacement the old lighting bulbs in traffic signs with the new LED bulbs which are energy efficient. It was a pilot project that made annual savings about 70,000KM (50,000KM for electrical energy and 20,000KM for maintenance) (www.tuzlanski.ba, 2012).

LED traffic light signs in Tuzla

The city of Tuzla is very positive example of the energy efficiency care and it is a leading city in Bosnia and Herzegovina when it comes to energy saving. In order to achieve better energy efficiency all of the traffic light bulbs in Tuzla have been replaced by modern LED lamps. Half of the funding is provided by the UNDP project that invests in achieving better energy efficiency for so many years. The other half is provided by the municipality budget (full price of the project was 180,000KM). The replacement project of old lamps with the power of 75W with the new LED lamps in traffic signal lighting included 950 existing semaphore lamps with the new LED lamps, as well as placing 71 LED new lamps at intersections in Tuzla. These results were expected:

-        Reduction of energy consumption for about 227MWh per year (LED lamps need about ten times less energy than the classical lamps for the same light output)

-        savings about 40,000KM (e.g. for one intersection electrical energy bill was 300KM when the classical lamps were illuminating it, but with the LED lamps the bill is 50KM)

-        CO2 emission reduction

-        traffic participants safety increase

-        semaphore light system reliability increase

-        investment return period is three to four years

One of the goals of improving the traffic lighting signals is also harmonization of traffic signal equipment with the Act of the basics of traffic security on the roads of Bosnia and Herzegovina.

LED diodes in semaphores are much more reliable than classical bulbs because they last much longer and probability of outage is smaller because the LED semaphore is matrix of LED diodes which doesn't stop working at the same time. It is a significant advantage when it is compared with the classical bulbs with the power of 75W which lasts for a year in average with frequent disruptions of traffic signals which confuses traffic participants and can cause the accidents.

The information below comes from the Department of public utilities, construction and operations of local communities in Tuzla municipality.

Costs of traffic signal lights with classical bulbs (average values for the entire traffic signal lights) were:

Monthly electrical energy consumption (kWh)

Annual electrical energy consumption

(kWh)

Monthly costs for electrical energy

(KM)

Annual costs for electrical energy

(KM)

22 289,40

271 187,70

4 012, 09

48 813,79

The following table shows the estimated costs and savings on an annual basis:

Estimated costs of replacing the classical bulbs with LEDs (KM)

Evaluation of energy savings (kWh)

Evaluation of energy savings (KM)

Evaluation of savings in maintenance costs (KM)

Estimate savings of the environmental impact (tCO2)

Estimate savings of the environmental impact (tSO2)

354 563,50

226 914,66

40 844,64

20 091,60

164,928

2,27

Total reduction of electricity consumption and total financial savings in the next 10 years: [1]

Year

Reduction of electricity consumption (MWh)

Total financial savings (KM)

1

226,91

60 936,24

2

453,83

121 872,48

3

680,74

182 808,72

4

907,66

243 744,96

5

1 134,57

304 681,19

6

1 361,49

365 617,43

7

1 588,40

426 553,67

8

1 815,32

487 489,91

9

2 042,23

548 426,15

10

2 269,15

609 362,39

Payback period = Investment/Annual savings = 354 563.50/60 936.24 = 5.8 years.

Total reduction of greenhouse gas emissions on an annual basis:

Electrical energy consumption reduction (kWh)

Sulfur dioxide SO2 (kg)

Nitrogen oxides NOx (kg)

The ash particles (kg)

Carbon dioxide CO2 (kg)

226 914,66

2 269,15

567,29

453,83

164 928,38

The benefit of this project will have all the citizens of Tuzla and all those who come to Tuzla or travel through Tuzla. In some way, people are safer, life quality is improved and people are motivated to stay and there comes the social life development.

Semafori LED tizla1
Intersection in Tuzla before semaphores replacement
(Source: Department of public utilities in Municipality of Tuzla)
Semafori LED tizla2
Intersection in Tuzla after semaphores replacement
(Source: Department of public utilities in Municipality of Tuzla)

The city of Tuzla should not be unique in Bosnia and Herzegovina after the modernization of traffic signal lights. This example should follow the whole country because the museum material should be in museum and the advantages of LED technology simply must be priority.

Author: MSc. Edina Hasanspahić

Source: BhDOCumentary

* * *

Thanks to Tuzla Municipality – Department of public utilities, construction and operations of local communities for provided data and photographs

Literature and Internet

  • Krvar Damir, Primjena LED i solarne tehnologije u prometnoj signalizaciji, Sveučilište u Zagrebu, Fakultet prometnih znanosti, Zagreb, Oktobar 2009, 3-4.
  • Milojević Vladimir, Razvoj semafora - Od gasa do diode, Planeta - Magazin za nauku, istraživanja i oktrića, www.planeta.org.rs /pogledano: 29.januar 2016. godine/
  • www.tuzlanski.ba, Štedljivi semafori postavljeni u cijeloj Tuzli, 28. novembar 2012.
  • www.mic-led.eu/catalog/, 28.12.2015.
  • IZVJEŠTAJ – Projekat Energetske efikasnosti, Projekat broj 001, Općina Tuzla, ''LED semaforska signalizacija''

[1] Data were taken from a Study of the electrical energy savings from the traffic signal lights in the City of Tuzla

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