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Signalization Safety and Driver Behavior Study with Flashing Green and Amber Time

Signalization Safety and Driver Behavior Study with Flashing Green and Amber Time at Signalized Intersections in Istanbul Authors: Ersoy Pehlivan, Sencer Oktav , Rahime Gunay ISBAK Inc. Istanbul , Turkey. CONTENT. Starting Point Signalization in Istanbul Purpose of the Study

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Signalization Safety and Driver Behavior Study with Flashing Green and Amber Time

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  1. Signalization Safety and Driver Behavior Study with Flashing Green and Amber Time at Signalized Intersections in Istanbul Authors: Ersoy Pehlivan, Sencer Oktav, Rahime Gunay ISBAK Inc. Istanbul,Turkey

  2. CONTENT • StartingPoint • Signalization in Istanbul • Purpose of theStudy • Methods & Research • Application • Conclusions

  3. ISTANBUL in BRIEF 8th Largest city : 5.4 sqkm Population (2010): ~12,6 Million Daily Trip : ~ 21 M. T Total Vehicle : ~ 2,6 M. Total Active Vehicle : 1,7-1,9 M. Daily Addition: ~ 400 veh. /day Total RoadNetwork : 25.000 Km Daily Trips betweentwocontinents : ~ 1.3 M.

  4. SIGNALIZATION in ISTANBUL Figure of Signalized Intersections (1950points) in Istanbul Metropolitan Area

  5. STARTING POINT A basic e-mail (tkm.ibb.gov.tr): “….Yellowtime is tooshort in RedLightEnforcementSystem (2 sec.) I don't have enoughtime to stop my car. That is why, must be green flashing application at alljunctionswhichareequippedwithEnforcementSystem.” Anotherphonecall (44 44 154): “…When the green starting to flash should I ready to stop? oropposite; accelerate and pass the intersection? Howthedrivers will deal with this uncertainty? “

  6. STARTING POINT At the beginning, there was a difference of opinionbetweenthe MetropolitanMunicipalitytransportationdepartment officialsworking on road safety, signalization and enforcementsystems. “…FlashingGreen, is it a sufficientway to preventing violations?Or else thedriverswill step on thegas?”

  7. SIGNALIZATION in ISTANBUL NO AMBER or NO RED+AMBER between RED to GREEN in ISTANBUL >>> LESS STARTING LOST TIME SUSPECT 

  8. PURPOSE OF THE STUDY Toexamine drivers' behavior when the signal is operated with andwithout the flashing green application as well as when the duration of the yellow changeinterval is extended at signalized intersections in Istanbul Metropoliten Area.

  9. METHODS & RESEARCH Weknowthat the approaching speed and distance to the intersection are the 2 most important things that affect the driver’s behavior. In addition, Theotherstudies showed theeffects of the yellow change interval and flashing green on stopping time at the stop line when the drivers proceed at a constant speed.

  10. METHODS & RESEARCH InAustria (since 1969) , sameas Israel and Cuba: Green>Green Flashing>Amber>Red>Amber+Red> In Spain:instead of flashing green: “Yellow+Green”is used together. InAustria, Canada, Turkey, Mexico, Russia, Slovenia, Lithuania, Israel THE MESSAGE: “a flashing green light is used in intersections to indicate that signal is going to change from green to red soon.” In USA, France, Italy, France, Belgium and some other EU countries Yellow+Red signal beforethegreen was abandoned (same as Istanbul but not as otherTurkishcities). MUTCD 2009: Chapter 4D, item D of paragraph-3 states specifically, "A flashing green signal indication has no meaning and shall not be used."

  11. METHODS & RESEARCH The drivers in Austria tend to stop earlier. Some 3% stop already duringthe period covered by the flashing green and 70-80% by end of the amber (7-8 s period isincluded due to the one approach in Linz with a four second amber duration). In Germany & Switzerland only about half as large (28-35% during the 2-3 s potential greeninterval). This response leads to a longer interval during which a following car driver cannotbe sure, how the car driver in front will decide. (H Köll, M Baderand KW Axhausen, 2002)

  12. METHODS & RESEARCH • WithReference to Köll, BaderandAxhausen (2002): • Theflashinggreen in Austria • is associatedwith a substantialincrease of earlystops, • producesa largeoptionzone, wheredrivers can bothsafely stop & pass. • thedilemma zoneis minimised. Thislargeoptionzonegenerates a period of uncertainty, where a driverfollowingcannoteasilypredict, ifthe car in frontwill stop orcross. • thechoicemodelshighlightedhigherspeedsandlowerdistances to the stop linereducethelikelihood to stop. • No othervariable had a significantimpactwhichcould be separatedfromthespecificmeasurementlocations.

  13. METHODS & RESEARCH AS a CONTINUING STUDY (to followKöll, BaderandAxhausen): 8 signalizedintersections on themainroad(Kennedy Street) of theEasternpart of thePeninsulain Istanbulwerechosen as test sites in bothupstream (sectionB) anddownstream (sectionA) directionsaccording to theassignedscenarios. 3 scenariosarediscussed:

  14. METHODS & RESEARCH

  15. METHODS & RESEARCH

  16. METHODS & RESEARCH

  17. APPLICATION PHASE • According to theresolution: • Implemented in 1860 signalizedintersections in 3weeks. • Flashing green was terminated and the duration of yellow change interval is extended to minimum 4 seconds. • Yellowchange interval time was extended from a minimum of 2 seconds to 3 seconds. • Durationof the yellow change interval was increased from 3 seconds to 4 seconds where the "Red Light Enforcement" application was used.

  18. APPLICATION PHASE

  19. APPLICATION PHASE Eng.version: ScreenSavers Turkishversion:

  20. CONCLUSIONS-1 • experimentalfieldresultshaveshownthat; • NO NEGATIVE EFFECTS of TERMINATING theGREEN FLASH on CAPACITY ofINTERSECTIONS • NO SIGNIFICANT DECREASE in nr of VEHICLES PASSING THROUGH DURING the GREEN PERIODand CONVERSELY, INCREASE from 1-5 %.

  21. CONCLUSIONS-2 experimental fieldresultshaveshownthat; • RED-LIGHT VIOLATIONS DECREASED fromabout 0.5-2% to about0-0.7%. • VEHICLES PASSING DURING theYELLOW-CHANGE INTERVAL INCREASE from0.5 to 2% • PROPORTIONALLY withtheEXTENSION of the YELLOW CHANGE INTERVAL.

  22. CONCLUSIONS

  23. CONCLUSIONS :( No complaints (zero) has beenreported. A descriptive e-mail has beenwrittenoutforthecitizenswhohave a complainedaboutthisissue. Discussed with the taxi drivers workingnearthestudyarea. Positivefeedbacksarenotedaboutincreasing of yellow time. They agreedthatthe benefits of green flashingareexaggerated. Dissemination: Final Report was sent to the other transportationdepartments. @ TAXI

  24. Thisstudyhas been proven that the extension of the yellow time is much more effective on drivers than the flashing green. ThankYou, GoshinsetsuNiArigatoo Ersoy Pehlivan www.isbak.com.tr • References: • “Driver Behavior under the Green Signal Countdown Information”. http://ir.lib.ncku.edu.tw/bitstream/.pdf • “H Köll, M Baderand KW Axhausen,2002, Driver behavior during flashing green before amber: A comparative study”. http://ecollection.library.ethz.ch/eserv/eth:25449/eth-25449-01.pdf , Zurich, Swiss • “Non-motorized Vehicle Drivers Behavior with Flashing Green and Green Countdown atIntersections: A ComparativeStudy”. //ftp.hsrc.unc.edu/pub/TRB2011/data/papers/11-4220.pdf. • MUTCD, 2009, FHWA, USA

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