Abstract
Traffic density is an essential parameter for assessing the performance of uninterrupted facilities during planning, design and operations. This study reviews and evaluates existing density estimation methods. The density estimation methods are classified into two categories: definition of concept (DOC) methods and automated methods. The traditional approach includes aerial photographic, fundamental traffic-flow equation, Edie’s, and cumulative input-output methods. The automated approach includes the occupancy method, filtering method, and integrated method. In addition, the strengths, weaknesses, opportunities, and threats (SWOT) analysis for the preceding methods is conducted. The SWOT analysis will be helpful to researchers and practitioners in selecting the appropriate density estimation method based on its relative merits. Finally, guidelines for using various density methods for heterogeneous and homogeneous traffic are presented.
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Data Availability Statement
This is a state-of-the-art review paper. The data used for this research paper will be made available based upon request.
Acknowledgments
The authors are grateful to four anonymous reviewers for their thorough and helpful comments.
References
Ajitha, T., L. Vanajakshi, and S. C. Subramanian. 2015. “Real-time traffic density estimation without reliable side road data.” J. Comput. Civ. Eng. 29 (2): 04014033. https://doi.org/10.1061/(ASCE)CP.1943-5487.0000310.
Aljamal, M. A., M. Farag, and H. A. Rakha. 2020. “Developing data-driven approaches for traffic density estimation using connected vehicle data.” IEEE Access 8 (Dec): 219622–219631. https://doi.org/10.1109/ACCESS.2020.3042612.
Ameena P., V. Lelitha, S. C. Subramanian, and H. Manda. 2009. “Prediction of traffic density for congestion analysis under Indian traffic conditions.” In Proc., 12th Int. IEEE Conf. on Intelligent Transportation Systems. New York: IEEE.
Angel, A., D. Chandnani, M. Hickman, and P. Mirchandani. 2001. Automated vehicle identification and estimation of traffic flow variables using video from low-flying moving platforms. Phoenix: Univ. of Arizona.
Arasan, V. T., and G. Dhivya. 2010. “Simulation of highly heterogeneous traffic flow.” In Proc., 24th European Conf. on Modelling and Simulation, 1–87. Kuala Lumpur, Malaysia: Univ. of Nottingham Malaysia.
Asha, A., V. Lelitha, and C. Subramanian. 2011. “Traffic density estimation under heterogeneous traffic condition using data fusion.” In Proc., IEEE Intelligent Vehicles Symp. New York: IEEE.
Asha, A., G. Ramadurai, and L. Vanajakshi. 2014. “Data fusion-based traffic density estimation and prediction.” J. Intell. Transp. Syst. 18 (4): 367–378. https://doi.org/10.1080/15472450.2013.806844.
Astarita, V., R. L. Bertini, and G. Guido. 2005. “The estimation of traffic flow parameters from instrumented vehicles counts.” In Proc., 84th Annual Meeting of TRB. Washington, DC. Transportation Research Board.
Athol, P. 1965. Vol. 72 of Interdependence of certain operational characteristics within a moving traffic stream. Washington, DC: Highway Research Board, National Research Council.
Banks, J. 1995. “Another look at a priori relationships among traffic flow characteristics.” Transp. Res. Rec. 1510: 1–10.
Bham, G. H., and R. F. Benekohal. 2004. “A high fidelity traffic simulation model based on cellular autómata and car-following concepts.” Transp. Res. Part C: Emerging Technol. 12 (1): 1–32. https://doi.org/10.1016/j.trc.2002.05.001.
Bharadwaj, N., P. Kumar, A. Mane, S. Arkatkar, A. Bhaskar, and G. Joshi. 2015. “Comparative evaluation of density estimation methods on different uninterrupted roadway facilities: Few case studies in India.” In Proc., 3rd Conf. of Transportation Research Group of India. Bangalore, Karnataka, India: Transportation Research Group of India.
Bharadwaj, N., P. Kumar, A. Mane, S. Arkatkar, A. Bhaskar, and G. Joshi. 2017. “Comparative evaluation of density estimation methods on different uninterrupted roadway facilities: Few case studies in India.” Transp. Dev. Econ. 3 (1): 1–14. https://doi.org/10.1007/s40890-016-0031-8.
Bhaskar, A., E. Chung, and A. G. Dumont. 2010. “Analysis for the use of cumulative plots for travel time estimation on signalized network.” Int. J. Intell. Transp. Syst. Res. 8 (3): 151–163. https://doi.org/10.1007/s13177-010-0012-y.
Bhaskar, A., T. Tsubota, L. M. Kieu, and E. Chung. 2014. “Urban traffic state estimation: Fusing point and zone-based data.” Transp. Res. Part C: Emerging Technol. 48 (Nov): 120–142. https://doi.org/10.1016/j.trc.2014.08.015.
Bhouri, N., H. Hadj-Salem, M. Papageorgiou, and J. M. Blosseville. 1988. “Estimation of traffic density on motorways.” Traffic Eng. Control 29: 579–583.
Cassidy, M., and B. Coifman. 1997. “Relation among average speed, flow, and density and the analogous relation between density and occupancy.” Transp. Res. Rec. 1591 (1): 1–6. https://doi.org/10.3141/1591-01.
Cassidy, M., and B. Coifman. 2014. Relation among average speed, flow, and density and analogous relation between density and occupancy. Transportation Research Record No. 1591. Washington, DC: Transportation Research Record.
Chang, M., and D. Gazis. 1975. “Traffic density estimation with consideration of lane changing.” Transp. Sci. 9 (4): 308–320. https://doi.org/10.1287/trsc.9.4.308.
Chari, S. R., and K. M. Badarinath. 1983. “Study of mixed traffic stream parameters through time-lapse photography.” Highway Res. Bull. 20: 57–83.
Cremer, M., and K. Putensen. 1993. “Monitoring of traffic density profiles using measurements from loop detectors and vehicle trip data.” In Proc., Advanced Traffic Management Conf.: Large Urban Systems. Washington DC: Federal Highway Administration.
Daganzo, C. F. 1994. “The cell transmission model: A dynamic representation of highway traffic consistent with the hydrodynamic theory.” Transp. Res. Part B: Methodol. 28 (4): 269–287. https://doi.org/10.1016/0191-2615(94)90002-7.
Davis, G., and J. G. Kang. 1994. “Estimating destination-specific traffic densities on urban freeways for advanced traffic management.” Transp. Res. Rec. 1457 (1): 143–148.
Easa, S. M. 1982. “Selecting two-regime traffic-flow models.” Transp. Res. Rec. 869: 25–36.
Easa, S. M., and A. D. May. 1980. “Generalized procedures for estimating single- and two-regime traffic flow models.” Transp. Res. Rec. 772: 24–37.
Edie, L. 1963. “Discussion on traffic stream measurements and definitions.” In Proc., 2nd Int. Symp. on the Theory of Traffic Flow. Paris: Organisation for Economic Co-operation and Development.
Edie, L. C. 1965. “Discussion of traffic stream measurements and definitions.” In Proc., 2nd Int. Symp. on the Theory of Traffic Flow, edited by J. Almond, 139–154. Paris: Organisation for Economic Co-operation and Development.
Edie, L. C. 1974. Traffic science. New York: Wiley.
Gazis, D., and C. Liu. 2003. “Kalman filtering estimation of traffic counts for two network links in tandem.” Transp. Res. Part B: Methodol. 37 (8): 737–745. https://doi.org/10.1016/S0191-2615(02)00059-0.
Gazis, D., and M. Szeto. 1974. “Design of density-measuring systems for roadways.” Transp. Res. Rec. 495: 44–52.
Gerlough, D. L., and M. J. Huber. 1975. Traffic flow theory: A monograph. Washington, DC: Transportation Research Board.
Ghosh, D., and C. H. Knapp. 1978. “Estimation of traffic variables using a linear model of traffic flow.” Transp. Res. 12 (6): 395–402. https://doi.org/10.1016/0041-1647(78)90027-8.
Greenshields, B. 1948. “The potential use of aerial photographs in traffic analysis.” In Proc., Highway Research Board. Washington, DC: National Academy of Sciences-National Research Council.
Greenshields, B. 1960. “The density factor in traffic flow.” Traffic Eng. 30: 26.
Greenshields, B., J. Thompson, H. Dickinson, and R. Swinton. 1934. “The photographic method of studying traffic behavior.” In Vol. 13 of Proc., Highway Research Board, 382–399. Washington, DC: National Academy of Sciences-National Research Council.
Hall, F. L. 1986. “The relationship between occupancy and density.” In Transportation forum. Ottawa: Transportation Association of Canada.
Hall, F.L., and B.N. Persaud. 1989. “Evaluation of speed estimated made with single-detector data from freeway traffic management systems” Transp. Res. Rec. 1232 (1): 9–16.
Haynes, J. 1965. “Some considerations of vehicular density on urban freeways.” Highway Res. Board Rec. 99: 59–80.
HCM. 1985. Highway capacity manual. Washington, DC: Transportation Research Board.
HCM. 1994. Highway capacity manual. Washington, DC: Transportation Research Board.
HCM. 2000. Highway capacity manual. Washington, DC: Transportation Research Board.
HCM. 2010. Highway capacity manual. Washington, DC: Transportation Research Board.
Johnson, A. N. 1928. “Aerial survey of highway traffic between Baltimore and Washington.” Highway Res. Board 8: 106–115.
Junghans, M., H. J. Jentschel, and A. Leitch. 2002. “An approach to video based wide area traffic surveillance.” In Proc., 9th World Congress on Intelligent Transport Systems. Washington, DC: Transportation Research Board.
Khanna, S. K., L. M. Patel, and S. R. Chari. 1976. “Study of traffic flow characteristics on Roorkee Hardwar road during Kumbh-Mela.” Indian Highways 4 (7): 22–39.
Kumar, S. V., L. Vanajakshi, and S. C. Subramanian. 2011. “A model-based approach to predict stream travel time using public transit as probes.” In Proc., IEEE Intelligent Vehicles Symp. (IV). New York: IEEE Intelligent Transportation Systems Society.
Kumar, V. M., and S. K. Rao. 1998. “Headway and speed studies on two-lane highways” Indian Highways 26 (5): 23–36.
Kurkjian, A., S. Gershwin, and P. Houpt. 1980. “Estimation of roadway traffic density on freeways using presence detector data.” Transp. Sci. 14 (3): 232–261. https://doi.org/10.1287/trsc.14.3.232.
Leonard, J. D., and D. Ni. 2006. “Direct methods of determining traffic stream characteristics by definition.” In Proc., 85th TRB Annual Meeting. Washington, DC: Transportation Research Board.
Li, Y. 2008. “Short-term prediction of motorway travel time using ANPR and loop data” J. Forecast. 27: 507–517. https://doi.org/10.1002/for.1070.
Lopez-Lopez, R., and P. Houpt. 1978. Estimation of traffic variables using point processing techniques. Cambridge, MA: Massachusetts Institute of Technology.
Makigami, Y., G. Newell, and R. Rothery. 1971. “Three-dimensional representation of traffic flow.” Transp. Sci. 5 (3): 302–313. https://doi.org/10.1287/trsc.5.3.302.
Makigami, Y., H. Sakamoto, and M. Hayashi. 1985. “Analytical method of traffic flow using aerial photographs.” J. Transp. Eng. 111 (4): 377–394. https://doi.org/10.1061/(ASCE)0733-947X(1985)111:4(377).
Mallikarjuna, C., and K. R. Rao. 2006. “Area occupancy characteristics of heterogeneous traffic.” Transportmetrica 2 (3): 223–236. https://doi.org/10.1080/18128600608685661.
May, A. D. 1962. California freeway operations study. Chatsworth, CA: Thompson Ramo Wooldridge.
May, A. D. 1990. Traffic flow fundamentals. Upper Saddle River, NJ: Prentice-Hall.
Morarescu, I. C., and C.C. D. Wit. 2011. “Highway traffic model-based density estimation.” In Proc., American Control. New York: IEEE.
Mũnoz, L., X. Sun, R. Horowitz, and L. Alvarez. 2006. “A piecewise linearized cell transmission model and parameter calibration methodology.” In Proc., 85th Annual Meeting of the Transportation Research Board. Washington, DC: Transportation Research Board.
Nahi, N. E., and A. N. Trivedi. 1973. “Recursive estimation of traffic variables: Section density and average speed.” Transp. Sci. 7 (3): 269–286. https://doi.org/10.1287/trsc.7.3.269.
Nanthawichit, C., T. Nakatsuji, and H. Suzuki. 2003. “Application of probe vehicle data for real time traffic state estimation and short-term travel time prediction on a freeway.” In Proc., 82nd Transportation Research Board Annual Meeting. Washington, DC: Transportation Research Board.
Nazer, P. A. 2001. “Density of mixed traffic stream from the speeds of individual vehicles.” Traffic Eng. Control 42 (9): 308–310.
Obrien, E., A. Lipari, and C. Caprani. 2011. “Estimation of density and gaps in congested traffic.” In Proc., Irish Transportation Research Network Annual Conf. (ITRN 2011). Cork, Ireland: Univ. College Cork.
Okutani, I., and Y. J. Stephanedes. 1984. “Dynamic prediction of traffic volume through Kalman filter theory.” Transp. Res. Part B: Methodol. 18 (1): 1–11. https://doi.org/10.1016/0191-2615(84)90002-X.
Ozkurt, C., and F. Camci. 2009. “Automatic traffic density estimation and vehicle classification for traffic surveillance systems using neural networks” Math. Comput. Appl. 14 (3): 187–196. https://doi.org/10.3390/mca14030187.
Padiath, A., L. Vanajakshi, and S. C. Subramanian. 2010. “Estimation of traffic density under Indian traffic conditions.” In Proc., 89th Transportation Research Board Annual Meeting. Washington, DC: Transportation Research Board.
Papageorgiou, M., C. Diakaki, V. Dinopoulou, A. Kotsialos, and Y. Wang. 2003. “Review of road traffic control strategies.” In Vol. 91 of Proc., IEEE, 2043–2067. New York: IEEE.
Qiu, T. Z., X. Y. Lu, A. H. Chow, and S. E. Shladover. 2010. “Estimation of freeway traffic density with loop detector and probe vehicle data.” Transp. Res. Rec. 2178 (1): 21–29. https://doi.org/10.3141/2178-03.
Saberi, M., H. S. Mahmassani, T. Hou, and A. Zockaie. 2014. “Estimating network fundamental diagram using three-dimensional vehicle trajectories: Extending Edie’s definitions of traffic flow variables to networks.” Transp. Res. Rec. 2422 (1): 12–20. https://doi.org/10.3141/2422-02.
Sahoo, P. K., S. K. Rao, and V. M. Kumar. 1996. “A study of traffic characteristics on two stretches of national highway no. 5.” Indian Highways 24 (4): 11–17.
Sheu, J. 1999. “A stochastic modelling approach to dynamic prediction of section-wide interlane and intra-lane traffic variables using point detector data.” Transp. Res. Part A: Policy Pract. 33 (2): 79–100.
Singh, B. 1999. “Simulation and animation of heterogeneous traffic on urban roads.” Ph.D. thesis, Dept. of Civil Engineering, Indian Institute of Technology.
Singh, K., and B. Li. 2012. “Estimation of traffic densities for multilane roadways using a Markov model approach.” In Vol. 59 of Proc., IEEE Transactions on Industrial Electronics, 4369–4376. New York: IEEE.
Stanková, K., and B. D. Schutter. 2010. “On freeway traffic density estimation for a jump Markov linear model based on Daganzo’s cell transmission model.” In Proc., 13th Int. IEEE Conf. on Intelligent Transportation Systems (ITSC 2010), 13–18. New York: IEEE.
Sun, X., L. Mufioz, and R. Horowitz. 2003. “Highway traffic state estimation using improved mixture Kalman filters for effective ramp metering control.” In Proc., 42nd IEEE Conf. on Decision and Control Maui. New York: IEEE.
Tabibiazar, A., and O. Basir. 2011. “Kernel-based optimization for traffic density estimation in ITS.” In Proc., IEEE Vehicular Technology Conf., 1–5. New York: IEEE. https://doi.org/10.1109/VETECF.2011.6093194.
Tampere, C. M. J., and L. H. Immers. 2007. “An extended Kalman filter application for traffic state estimation using CTM with implicit mode switching and dynamic parameters.” In Proc., IEEE Intelligent Transportation Systems Conf., 209–216. New York: IEEE Intelligent Transportation Systems Society.
Tiwari, G., P. Joseph, E. Fazio, and N. Chatteerjee. 2008. “Continuity equation validation for nonhomogeneous traffic.” J. Transp. Eng. 134 (3): 118–127. https://doi.org/10.1061/(ASCE)0733-947X(2008)134:3(118).
Treiber, M., and A. Kesting. 2013. “The Lighthill–Whitham–Richards model.” In Traffic flow dynamics. Berlin: Springer.
Umer,T., Z. Ding, B. Honary and H. Ahmad. 2010. “Implementation of microscopic parameters for density estimation of heterogeneous traffic flow for VANET.” In Proc., 7th Int. Symp. on Communication Systems, Networks & Digital Signal Processing (CSNDSP 2010), 66–70. New York: IEEE. https://doi.org/10.1109/CSNDSP16145.2010.5580460.
Vanajakshi, L., and L. R. Rilett. 2004. “Loop detector data diagnostics based on conservation of vehicle principle.” J. Transp. Res. Rec. 1870 (1): 162–169. https://doi.org/10.3141/1870-21.
Wang, Y., and M. Papageorgiou. 2005. “Real-time freeway traffic state estimation based on extended Kalman filter.” Transp. Res. Part B: Methodol. 39 (2): 141–167. https://doi.org/10.1016/j.trb.2004.03.003.
Wardrop, J. G. 1952. “Some theoretical aspects of road traffic research.” In Vol. 1 of Proc., Institution of Civil Engineers, PART II. London: Institution of Civil Engineers.
Wassantachat, T., Z. Li, J. Chen, Y. Wang, and E. Tan. 2009. “Traffic density estimation with on-line SVM classifier.” In Proc., Sixth IEEE Int. Conf. on Advanced Video and Signal Based Surveillance AVSS ‘09, 13–18. New York: IEEE.
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Journal of Transportation Engineering, Part A: Systems
Volume 149 • Issue 2 • February 2023
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© 2022 American Society of Civil Engineers.
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Published online: Nov 21, 2022
Published in print: Feb 1, 2023
Discussion open until: Apr 21, 2023
ASCE Technical Topics:
- Aerial photography
- Automation and robotics
- Building design
- Design (by type)
- Engineering fundamentals
- Geomatics
- Highway and road design
- Information management
- Infrastructure
- Mathematics
- Parameters (statistics)
- Statistics
- Surveying methods
- Systems engineering
- Terminology and definition
- Traffic analysis
- Traffic engineering
- Traffic management
- Traffic volume
- Transportation engineering
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