Article
DEVELOPING FREE-FLOW SPEED MODELS FOR URBAN ROADS UNDER HETEROGENEOUS TRAFFIC CONDITIONS
DOI: 10.7708/ijtte.2017.7(4).04
7 / 4 / 443-460 Pages
Author(s)
Srijith Balakrishnan - Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, USA -
Abstract
Free-flow speed (FFS) is the desired speed that drivers choose when no (or very less number of) vehicles are present in the road segment. FFS is an important parameter of traffic flow that decides the level of service and capacity aspects of various types of highway facilities. Estimation of FFS is extremely time consuming and requires extensive human resource and capital. Hence, a FFS model can be a solution to bring down the above difficulties while ensuring satisfactory prediction of FFS. In countries like India, a widely used method of estimating FFS is to collect vehicle speeds from field during low volume hours. However, this method requires significant amount of time, human resource and capital for studies on large road networks. Hence, it is essential to develop models to predict free-flow speeds. It is important that models are capable of capturing the free-flow speed variations due to local road factors. Majority of the existing free-flow speed models are developed under homogeneous traffic conditions, in which passenger cars dominate the vehicle composition. However, the traffic condition in emerging economies like India is heterogeneous in nature characterized by the presence of multiple vehicle categories with varying physical and dynamic characteristics. The present paper attempts to investigate the influence of different road factors on FFS on urban roads of Chennai, India. The paper also tries to capture the FFS variations across different classes of vehicles and develop FFS prediction models. The typical Indian traffic comprises significant percentage of slow moving vehicles like three-wheelers as well as fast moving sedans and SUVs. Composition of traffic and corresponding proportions of different classes are important factors that differentiate heterogeneous and homogeneous traffic. The presented models could explore the driver speed behavior with respect to the aforementioned factors into consideration.
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Acknowledgements:
The support for this work by the Centre of Excellence in Urban Transport at Indian Institute of Technology Madras, India, funded by the Ministry of Urban Development, Government of India, is gratefully acknowledged.
References:
Anjaneyulu, M.V.L.R.; Nagaraj, B.N. 2009. Modelling congestion on urban roads using speed profile data, Journal of Indian Road Congress 70: 65–74.
Balakrishnan, S.; Sivanandan, R., 2015. Influence of lane and vehicle subclass on free-flow speeds for urban roads in heterogeneous traffic, Transportation Research Procedia 10: 166–175.
Bang, K.L. 1995. Impact of side friction on speed-flow relationships for rural and urban highways. Bandung, Indonesia.
Bang, K.L.; Carlsson, A.; Palgunadi. 1995. Development of speed-flow relationships for Indonesian rural roads using empirical data and simulation, Transportation Research Record 1484: 24–32.
Cambridge Sytematics; Dowling Associates; System Metrics Group; Texas Transportation Institute. 2008. Cost-effective performance measures for travel time delay, variation, and reliability. Washington DC, United States: Transportation Research Board. 69 p.
Dixon, K.; Wu, C.-H; Sarasua, W; Daniel, J. 1999. Posted and free-flow speeds for rural multilane highways in Georgia, Journal of Transportation Engineering 125(6): 487–494.
Fazio, J.; Wiesner, B.N.; Deardoff, M.D. 2014. Estimation of free-flow speed, KSCE Journal of Civil Engineering 18(2): 646–650.
Figueroa, A.M.; Tarko, A.P. 2005. Speed factors on two-lane rural highways in free-flow conditions, Transportation Research Record: Journal of the Transportation Research Board 1912: 39–46.
Himes, S.C.; Donnell, E.T.; Porter, R.J. 2013. Posted speed limit: To include or not to include in operating speed models, Transportation Research Part A: Policy and Practice 52: 23–33.
Kadiyali, L.R.; Viswanathan, E.; Gupta, R.K. 1983. Free speeds of vehicles on Indian roads, Journal of Indian Road Congress 42(3).
Kyte, M.; Khatib, Z; Shannon, P; Kitchener, F. 2000. Effect of environmental factors on free-flow speed. In Fourth International Symposium on Highway Capacity. Maui, Hawaii, 108–119.
De Luca, M.; Lamberti, R.; Dell’Acqua, G. 2012. Freeway free flow speed: A case study in Italy. In 15th Meeting of the EURO Working Group on Transportation. Paris, France, 628–636.
Ma, Y.; Zeng, Y.; Yang, X. 2010. Impact of lane width on vehicle speed of urban arterials. In ICCTP 2010: Integrated Transportation Systems: Green, Intelligent, Reliable. Beijing, China: American Society of Civil Engineers, 1844–1852.
Madhu, E.; Reddy, T.S.; Madhu, S. V. 2004. Updating free speed models through mechanistic principles for Indian conditions, Journal of Advanced Transportation 38(2).
Moses, R.; Mtoi, E. 2013. Evaluation of free flow speeds on interrupted flow facilities, Tallahassee, United States. 65 p.
Odoki, J.B.; Kerali, H.G. 2000. Analytical Framework and Model Structure, Volume 4, PAIRC, Paris, France.
Rao, A.M.; Rao, K.R. 2015. Free speed modeling for urban arterials - A case study on Delhi, Periodica Polytechnica Transportation Engineering 43(3): 111–119.
Ross, M. 1994. Automobile fuel consumption and emissions: Effects of vehicle and driving characteristics, Annual Review of Energy and the Environment 19(1): 75–112.
Saifizul, A.A.; Yamanaka, H.; Karim, M.R. 2011. Empirical analysis of gross vehicle weight and free-flow speed and consideration on its relation with differential speed limit, Accident Analysis & Prevention 43(3): 1068–1073.
Schrank, D.; Eisele, B.; Lomax, T. 2012. TTI’s 2012 Urban Mobility Report. Texas Transportation Institute, College Station, Texas. 68 p.
Sun, D. 2010. Study of the effectiveness of nighttime and truck speed limits. In Traffic and Transportation Studies 2010. Reston, VA: American Society of Civil Engineers, 977–989.
Transportation Research Board. 2010. Highway Capacity Manual, Washington DC, United States: Transportation Research Board.
Tseng, P.Y.; Lin, F.B.; Shieh, S.L; 2005. Estimation of free-flow speeds for multilane rural and suburban highways, Journal of East Asian Society of Transportation Studies 6: 1484–1495.
Yagar, S.; Van Aerde, M. 1983. Geometric and environmental effects on speeds of two-lane highways, Transportation Research Part A: general 17(4): 315–325.
Yusuf, I.T. 2010. The factors for free-flow speed on urban arterials – Empirical evidences from Nigeria, Journal of American Science 6(12): 1487–1497.
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