Investigation on the Effects of Countdown Timers on Safety and Performance of Traffic at Signal Controlled Intersections

Document Type : Scientific - Research

Authors

1 Assistant Professor, Department of Civil Engineering, Yazd University, Yazd, Iran

2 MSc. Grad., Department of Civil Engineering, Yazd University, Yazd, Iran

Abstract

This article reflects the findings of a study on the impacts of countdown timers on safety and performance of traffic at signal controlled intersections.  Parameters such as late-stopping ratio, early start ratio, number of red light violations and number of accidents were examined to consider safety impacts of these timers.  Additionally, saturation flow rate, saturation headway and start-up delay parameters examined to compare capacity and traffic performance at 6 signalized intersections located in the Yazd and Sirjan cities where the countdown timers where left on and then switched off. Data required for this purpose was provided from the video recordings of video surveillance cameras. Comparison between the timer on and off situations indicated that the number of red light violations reduced by about 1.16%, when the timer was on, the number of accidents showed no clear variation and early start ratio increased by about 1.7% when the timer was on.  However, Mann-Whitney test based on a 95% Confidence interval showed that there was no significant difference between these two situations. Late-stopping ratio on average reduced by about 2.34% when the timer was on and Mann-Whitney test results showed that there was a significant difference between the two situations. .  Investigation on start-up delay parameter indicated that there was a significant difference between the two situations.  In this regard, start-up delay of all the intersections increased by about 22.8% when the timers were off. The t test for analyzing saturation headway and saturation flow rates indicated that there was no significant difference between the two situations. 

Keywords

References

-        حقانی ، م و شاه حسینی ، ز.  (1391) "برنامه ریزی حمل و نقل و مهندسی ترافیک به همراه مروری بر آمار و احتمالات"، کتاب آوا ، چاپ اول.
-        دهقانی ، نازلی  و ایران نژاد ، الناز (1390) "بررسی آثار شمارشگر های معکوس چراغ های راهنمایی بر عملکرد رانندگان "، دهمین کنفرانس مهندسی حمل و نقل و ترافیک ایران ، تهران ، سازمان حمل و نقل و ترافیک تهران ، معاونت حمل و نقل و ترافیک شهرداری تهران،
-       شرکت کنترل ترافیک تهران (1385) "بررسی چگونگی عملکرد شمارشگرهای نصب شده بر روی تقاطعات تهران"، www.tehrancontrol.tehran.ir، Date accessed: 2014/12/20
-Chen, H., Zhou, H. and Hsu, P. (2009) “What do we know about signal countdown timers?”, ITE Journal on the Web, Vol2, PP.72-76.
-Chen, I. C. , Chang, K. K., Chang, C. C. and Lai, C. H. (2007) “The impact evaluation of vehicular signal countdown displays”, Taiwan Institute of Transportation, Ministry of Transportation and Communications.
-Chiou, Y. C. and Chang, C. H. (2010) “Driver responses to green and red vehicular signal countdown displays: safety and efficiency aspects”, Accident Analysis and Prevention, Vol.  42, No 4 ,  pp. 1057-1065.
-Ibrahim, M., Karim, M. and Kidwai, F. (2008) “The effect of digital countdown display on signalized junction performance”, American Journal of Applied Science. Vol. 5, No 5, pp. 479–482.
-Islam, M. (2014) “Safety and efficiency benefits of traffic signal countdown timers: a driving simulator study”, Oregon State University, a Dissertation for Doctor of Philosophy.
-Kidwai, F., Kari, M. and Ibrahim, M. (2005) “Traffic flow analysis of digital countdown signalized urban intersection”, Proceeding of the Eastern Asia Society for Transportation Studies, Vol. 5, pp. 1301-1308.
-Köll, H., Bader, M. and Axhausen, K. (2004) “Driver behaviour during flashing green before amber: A comparative study”, Accident Analysis and Prevention. Vol. 36, No. 2 , pp. 273.280.
-Limanond, T., Chookerd, S. and Roubtonglang, N. (2009) “Effect of countdown timers on queue discharge characteristics of through movement at a signalized intersection”, Transportation Research Part C. Vol .17, No. 6, pp. 662-671.
-Limanond, T., Prajabok , P. and Tippayawong , K . (2010) “Exploring impact of countdown timers on traffic operations and driver behavior at a signalized intersection in Bangkok”, Transport Policy, Vol. 17, No. 6, pp. 420-427.
-Liu, P. R. Y, H., Wang, W., Ma, J. and Wang, S. H. (2012) “Evaluating the effects of signal countdown timers on queue discharge characteristics at signalized intersections in China”, Transportation Research Record: Journal of the Transportation Research Board, Transportation Research Board of the National Academies, Washington, D.C., No. 2286 ,  pp. 39–48.
-Lum, K. M. and Halim, H. (2006) “A before-and-after study on green signal countdown device installation”, transportation research part F. traffic psychological behavior. Vol. 9, No. 1, pp. 29–41.
-Ma, W., Liu, Y. and Yang, X. (2010) “Investigating the impacts of green signal countdown devices: empirical approach and case study in china”, ASCE Journal of Transportation Engineering, Vol. 136, No.11, pp. 1049–1055.
-Rijavec, R., Zakovsek, J. and Maher, T. (2013) “Acceptability of countdown signals at an urban signalized intersection and their influence on drivers behaviour", Promet-Traffic and Transportation, Vol. 25, No. 1, pp. 63-71.
-Sharma, A., Vanajakshi, L. and Rao, N. (2009) “Effect of phase countdown timers on queue discharge characteristics under heterogeneous traffic conditions”, Transportation Research Record. No. 2130, pp.93–100.

Files

History

  • Receive Date: 25 January 2016
  • Revise Date: 03 June 2016
  • Accept Date: 25 September 2016

Share

How to cite

Statistics