Optimal Sensor Placement for Freeway Travel Time Estimation
This article presents a modeling framework and a polynomial solution algorithm for determining optimal locations of point detectors used to compute freeway travel times. First, an objective function is introduced to minimize the deviation of estimated and actual travel times of all individual sub-segments of a freeway route. By discretizing the problem in both time and space, we formulate it as a dynamic programming model, which can be solved via a shortest path search in an acyclic graph. Numerical examples are provided to illustrate the model and algorithm using microscopic traffic simulation and GPS data from the Mobile Centuryexperiment recently conducted by the University of California, Berkeley, Nokia and California Department of Transportation (Caltrans).
KeywordsOptimal Sensor Link Travel Time Loop Detector Travel Time Estimation Actual Travel Time
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The authors would like to thank the four anonymous referees for their insightful comments and helpful suggestions on an earlier version of the paper. This research is partially supported by the California Department of Transportation (Caltrans).
- Al-Deek, H., and Emam, E.B. (2006) New methodology for estimating reliability in transporta-tion networks with degraded link capacities. Journal of Intelligent Transportation Systems, 10(3), 117-129.Google Scholar
- Amin, S. et al. (2008). Mobile century-using GPS mobile phones as traffic sensors: a field experiment. Proceedings of the 15th World congress on ITS, New York, NY, USA.Google Scholar
- Ban, X., Li, Y., Skabardonis, A. and Margulici, J.D. (2007). Performance evaluation of travel time methods for real time traffic applications. Proceedings of the 11th World Congress on Transport Research(CD-ROM).Google Scholar
- Bellman, R. and Dreyfus, S. (1962). Applied Dynamic Programming. Princeton University Press.Google Scholar
- Berkeley Transportation Systems (BTS04). Pems user guide, Version 5.2, 2004.Google Scholar
- Bertsekas, D.P. (1998). Network Optimization: Continuous and Discrete Models. Athena Scientific.Google Scholar
- California Center for Innovative Transportation (2007). Corridor Management Plan Demonstration. Final report for CCIT Task Order 3. Internet Link: http://www.calccit.org/resources/2007PDF/CCITTO3FinalReport-Jan5-07.pdf
- Coifman, B (2002). Estimating travel times and vehicles trajectories on freeways using dual loop detectors. Transportation Research Part A, 36(4), 351-364.Google Scholar
- Fujito, I., Margiotta, R., Huang, W. and Perez, W.A. (2006) The effect of sensor spacing on performance measure calculations. Proceedings of the 85th Annual Meeting of Transportation Research Board(CD-ROM).Google Scholar
- Jia, Z., Chen, C., Coifman, B. and Varaiya, P. (2001). Pems algorithms for accurate, real-time estimates of g-factors and speeds from single-loop detectors. Proceeding of IEEE ITS Annual Meeting, 536-541.Google Scholar
- Khattak, A., Kanafani, A. and Colletter, E.L. (1994). Stated and reported route diversion behavior: implications of benefits of advanced traveler information system. Transportation Research Record, 1464, 28-35.Google Scholar
- Kwon, J., McCullough, B., Petty, K. and Varaiya, P. (2006). Evaluation of PeMS to Improve the Congestion Monitoring Program. Technical report, Final Report for PATH TO 5319.Google Scholar
- Li, Z.C., Lam, W.H.K., Wong, S.C., Huang, H.J. and Zhu, D.L. (2007) Reliability evaluation for stochastic and time-dependent networks with multiple parking facilities. Networks and Spatial Economics, in press.Google Scholar
- Mirchandani, P., Gentili, M. and Ye, Y. (2007) Sensor locations on a network to monitor travel-time performance. Proceedings of the 3rd International Symposium on Transportation Network Reliability (INSTR07).Google Scholar
- Rice, J. and Zwet, E.V. (2001). A simple and effective method for predicting travel times on freeways. Proceedings of IEEE Intelligent Transportation Systems, 227-232.Google Scholar
- Sanwal, K.K. and Walrand, J. (1995) Vehicle as Probes. Technical Report UCB-ITS-PWP-95-11, California Path.Google Scholar
- Thomas, G.(1999) The relationship between detector location and travel characteristics on arterial streets. Institute of Transportation Engineers Journal, 69(10), 36-42.Google Scholar
- Work, D., Tossavainen, O.P., Blandin, S., Bayen, A., Iwuchukwu, T. and Tracton, K. (2008) An ensemble Kalman filtering approach to highway traffic estimation using GPS enabled mobile devices. Proceedings of the 47th IEEE Conference on Decision and Control.Google Scholar