Analysis of Speed Profiles at An Unsignalised Intersection for Left Turning Vehicles

Document Type : Research Paper


1 Ph.D Candidate, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran

2 Assistant Professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran

3 Assistant Professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran



Intersections are one of the elements that play an important role in urban networks. Analysis of drivers’ performance at unsignalised intersections is crucial, especially in left-turning movements due to their several inherent conflicts and variety of drivers’ maneuver types which affect traffic safety and capacity at such intersections, so the purpose of this paper is to introduce how the behaviour of drivers will be specified in left-turning at unsignalized intersection. For this study, traffic data were collected using a fixed digital camera. First, the vehicle speed profiles are categorized into descending-ascending slope (type (A)), the smooth descending-ascending slope (type (B)) and ascending slope (type (C)).The effects of the initial speed of left-turning vehicles, the exposure with other vehicles, and the vehicle type (i.e., taxi versus other vehicles) are investigated on the choice of speed profile. A multinomial logit model is utilized to explain how various variables influence the choice of speed profile. The estimated model indicates that the initial speed and the exposures are influential parameters. Also, vehicles with left exposure at intersections increase the drivers’ tendency for selecting type (A) profile while they have low to medium initial speeds when entering the intersections. For the vehicles with high initial speeds, most drivers pass the intersection with type (B) profile. Vehicles with low initial speeds and a low number of exposures increase the probability of selecting type (C) profile. Introduced method can be applied for simulation models at unsignalised intersection to show how drivers will behave in left-turning movements.


-Armand, A., Filliat, D. and Ibanez-Guzman, J (2013) “Modelling stop intersection approaches using gaussian processes”, In Intelligent Transportation Systems-(ITSC), 16th International IEEE Conference on (pp. 1650-1655). IEEE.
-Autey, J., Sayed, T andZaki, M (2012)“Safety evaluation of right-turn smart channels using automated traffic conflict analysis”, Accident Analysis and Prevention Vol.45, pp.120–130
-Boroujerdian, A., Karimi, A. and Seyedabrishami, S (2014) “Identification of Hazardous Situations using Kernel Density Estimation Method Based on Time to Collision, Case study: Leftturn on Unsignalized Intersection”, International Journal of Transportation Engineering, Vol.1, No.4, pp. 223-240
-Dias, C., Iryo-Asano, M. and Oguchi, T (2017) “Predicting optimal trajectory of left-turning vehicle at signalized intersection”, Transportation Research Procedia,Vol 21, pp.240-250.
-El-Basyouny, K. and Sayed, T. (2013) “Safety performance functions using traffic conflicts”, Safety Science, Vol.51, No.1, pp.160-164.
-Hensher, D.A., Rose, J.M. and Greene, W.H ( 2005) “Applied choice analysis: a primer. Cambridge University Press”.
-Kinovea software from
-Laureshyn, A., Åström, K. and Brundell-Freij, K ( 2009) “From speed profile data to analysis of behaviour: classification by pattern recognition techniques”, IATSS research, Vol.33, No.2, pp.88-98.
-Li, G., Wang, Y., Zhu, F., Sui, X., Wang, N., Qu, X. and Green, P (2019) “Drivers’ visual scanning behavior at signalized and unsignalized intersections: A naturalistic driving study in China”, Journal of Safety Research, 71, pp.219-229.
-Li, H., Li, S., Li, H., Qin, L., Li, S. and Zhang, Z (2016) “Modelling left-turn driving behaviour at signalized intersections with mixed traffic conditions”, Mathematical Problems in Engineering, Hindawi Publishing Corporation.
-Liu, M., Chen, Y., Lu, G. and Wang, Y (2017) “Modelling crossing behaviour of drivers at unsignalized intersections with consideration of riskperception”,Transportation research part F: traffic psychology and behaviour, Vol 45, pp.14-26.
-Lu, G., Liu, M., Wang, Y., & Yu, G (2012) “Quantifying the severity of traffic conflict by assuming moving elements as rectangles at intersection”, Procedia-Social and Behavioral Sciences, Vol.43, pp.255-264.
-Lu, G., Liu, M., Wang, Y., Wan, H. and Tian, D (2015) “Logit-Based analysis of drivers’ crossing behaviour at unsignalized Intersections in China”, Human factors, Vol.57, No.7, pp.1101-1114.
-Ma, Z., Xie, J., Qi, X., Xu, Y. and Sun, J (2017) “Two dimensional simulation of turning behaviour in potential conflict area of mixed flow intersections”, Computer Aided Civil and Infrastructure Engineering, Vol 32, No 5, pp.412-428
-Patil, G.R. and Pawar, D.S (2016) “Microscopic analysis of traffic behaviour at unsignalized intersections in developing world”, Transportation Letters, Vol 8, No 3, pp.158-166.
-Platho, M., Groß, H.M. and Eggert, J (2013) “Predicting velocity profiles of road users at intersections using configurations” ,In Intelligent Vehicles Symposium (IV), 2013 IEEE, pp. 945-951.
-Sun, J., Zhou, S.E., Li, K. and Ni, Y (2012) “Evaluation of safety factors at Chinese intersections”, In Proceedings of the Institution of Civil Engineers-Transport (Vol. 165, No. 3, pp. 195-204). Thomas Telford Ltd.
-Wolfermann, A., Alhajyaseen, W.K. and Nakamura, H (2011) “Modelling speed profiles of turning vehicles at signalized intersections”, In 3rd International Conference on Road Safety and Simulation RSS2011, Transportation Research Board TRB, Indianapolis, pp 1-17.
-Zhang, G., Qi, Y. and Chen, J (2016) “Exploring factors impacting paths of left-turning vehicles from minor road approach at unsignalized intersections”, Mathematical Problems in Engineering, Hindawi Publishing Corporation.