Abstract
Variable speed limits (VSL) aim to improve freeway mobility and safety by influencing collective behaviors of drivers. Thus, VSL benefits should be positively correlated with the VSL compliance level (CL). Surprisingly, a number of heuristic VSL control strategies have shown that VSL with increased CLs can, in fact, increase travel time. However, it has yet to be analyzed whether or not that outcome is because of the control strategy design or the CL. Some recent studies have shown that, regardless of CL, a proactive optimal VSL control provides mobility benefits; however, no evidence has been found to indicate which CL is most achievable in practice, nor has a description been found for the distribution of speed of a given VSL. The objective of this paper is to quantify the relative contribution of CLs with a proactive optimal VSL control toward improving mobility and safety. In this study, several CL-to-VSL strategies have been modeled after real-world driver behavior. To quantify the impact of CLs only, speed distributions are altered with the static speed limit. Then, the benefits are quantified by implementing a proactive optimal VSL control strategy with CLs. The simulation evaluation shows that both VSL mobility and safety benefits are positively correlated with increasing CLs. Specifically, the travel time, throughput, and collision probability are improved in the CL ranges of 5–15%, 6–8%, and 50–60%, respectively. The study findings will help guide transportation agencies in deploying VSL control by considering CL, so as to achieve maximum mobility and safety benefits.
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Acknowledgments
The authors would like to thank Ken Karunaratne, Iris Ye, Wai Cheung, Daniel Kabaroff, Matthew Knezevich, and Craig Walbaum from the traffic operation group at the City of Edmonton for providing the Whitemud Drive historical loop detector data. This research work was jointly supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, City of Edmonton, and Transport Canada.
References
Abdel-Aty, M., Cunningham, R. J., Gayah, V. V., and Hsia, L. (2008). “Dynamic variable speed limit strategies for real-time crash risk reduction on freeways.”, Transportation Research Board, Washington, DC, 108–116.
Abdel-Aty, M., Dilmore, J., and Dhindsa, A. (2006). “Evaluation of variable speed limits for real-time freeway safety improvement.” Accid. Anal. Prev., 38(2), 335–345.
Allaby, P., Hellinga, B., and Bullock, M. (2007). “Variable speed limits: Safety and operational impacts of a candidate control strategy for freeway applications.” IEEE Trans. Intell. Transp. Syst., 8(4), 671–680.
Bertini, R. L., Boice, S., and Bogenberger, K. (2006). “Dynamics of variable speed limit system surrounding bottleneck on German autobahn.”, Transportation Research Board, Washington, DC, 149–159.
Carlson, R. C., Papamichail, I., Papageorgiou, M., and Messmer, A. (2010). “Optimal mainstream traffic flow control of large-scale motorway networks.” Transp. Res. Part C, 18(2), 193–212.
Dervisoglu, G., Gomes, G., Kwan, J., Muralidharan, A., Horowitz, R., and Horowitz, R. (2009). “Automatic calibration of the fundamental diagram and empirical observations on capacity.” TRB 88th Annual Meeting Compendium of Papers (CD-ROM), Transportation Research Board of the National Academies, Washington, DC.
Giles, M. J. (2004). “Driver speed compliance in Western Australia: A multivariate analysis.” Transp. Policy, 11(3), 227–235.
Habtemichael, F. G., and Santos, L. D. P. (2013). “Safety and operational benefits of VSL under different traffic conditions and driver compliance levels.”, Transportation Research Board, Washington, DC, 7–15.
Hadiuzzaman, M. (2014). “Variable speed limit control to mitigate freeway congestion.” Ph.D. thesis, Dept. of Civil and Environmental Engineering, Univ. of Alberta, Edmonton, Canada.
Hadiuzzaman, M., and Qiu, T. Z. (2013). “Cell transmission model based variable speed limit control for freeways.” Can. J. Civ. Eng., 40(1), 46–56.
Hadiuzzaman, M., Qiu, T. Z., and Lu, X. Y. (2013). “Variable speed limit control design for relieving congestion caused by active bottleneck.” J. Transp. Eng., 358–370.
Hegyi, A., De Schutter, B., and Hellendoorn, J. (2005). “Optimal coordination of variable speed limits to suppress shock waves.” IEEE Trans. Intell. Transp. Syst., 6(1), 102–112.
Hellinga, B., and Mandelzys, M. (2011). “Impact of driver compliance on the safety and operational impacts of freeway variable speed limit systems.” J. Transp. Eng., 260–268.
Islam, M., Hadiuzzaman, M., Fang, J., Qiu, T. Z., and El-Basyouny, K. (2013). “Assessing mobility and safety impacts of a variable speed limit control strategy.”, Transportation Research Board, Washington, DC, 1–11.
Jonkers, E., Wilmink, I. R., Stoelhorst, H., Schreuder, M., and Polderdijk, S. (2011). “Results of field trials with dynamic speed limits in the Netherlands: Improving throughput and safety on the A12 freeway.” 14th Int. IEEE Conf. on Intelligent Transportation Systems, IEEE, New York, 2168–2173.
Kang, K., and Chang, G. (2006). “A robust model for optimal time-of-day speed control at highway work zones.” IEEE Trans. Intell. Transp. Syst., 7(1), 115–123.
Kang, K., Chang, G., and Zou, N. (2004). “Optimal dynamic speed-limit control for highway work zone operations.”, Transportation Research Board, Washington, DC, 77–84.
Kwon, E., Brannan, D., Shouman, K., Isackson, C., and Arseneau, B. (2007). “Development and field evaluation of variable advisory speed limit system for work zones.”, Transportation Research Board, Washington, DC, 12–18.
Lee, C., Hellinga, B., and Saccomanno, F. (2006). “Evaluation of variable speed limits to improve traffic safety.” Transp. Res. Part C: Emerging Technol., 14(3), 213–228.
Lin, P. W., Kang, K. P., and Chang, G. L. (2004). “Exploring the effectiveness of variable speed limit controls on highway work-zone operations.” J. Intell. Transp. Syst.: Technol. Plann. Oper., 8(3), 155–168.
Long, K., Yun, M., Zheng, J., and Yang, X. (2008). “Model predictive control for variable speed limit in freeway work zone.” Proc., 27th Chinese Control Conf. (CCC), IEEE, New York, 488–493.
Long, S., Gentry, L., and Bham, G. H. (2012). “Driver perceptions and sources of user dissatisfaction in the implementation of variable speed limit systems.” Transp. Policy, 23, 1–7.
Lu, X., Qiu, T. Z., Horowitz, R., Chow, A., and Shladover, S. (2011). “METANET model improvement for traffic control.” IEEE Conf. on Intelligent Transportation Systems, IEEE, New York, 2148–2153.
MATLAB [Computer software]. Natick, MA, MathWorks.
McMurtry, T., Saito, M., Riffkin, M., and Heath, S. (2008). “Variable speed limit signs: Effects on speed and speed variation in work zones.” TRB 85th Annual Meeting Compendium of Papers (CD-ROM), Transportation Research Board of the National Academies, Washington, DC.
Mohammadi, M. A., and Bham, G. H. (2011). “Vehicle speeds in work zones: An objective and subjective analysis.” TRB 91st Annual Meeting Compendium of Papers (CD-ROM), Transportation Research Board of the National Academies, Washington, DC.
Park, B. K., and Yadlepati, S. S. (2003). “Development and testing of variable speed limit logics at work zones using simulation.” TRB 82nd Annual Meeting Compendium of Papers (CD-ROM), Transportation Research Board of the National Academies, Washington, DC.
Su, D., Lu, X., Varaiya, P., Horowitz, R., and Shladover, S. E. (2011). “Variable speed limit and ramp metering design for congestion caused by weaving.” TRB 90th Annual Meeting Compendium of Papers (CD-ROM), Transportation Research Board of the National Academies, Washington, DC.
Sui, Y., and Young, R. K. (2013). “Analysis of speed compliance in rural variable speed limit system.” Presentation for the ITE Western District Annual Meeting, Phoenix, AZ.
TRB (Transportation Research Record). (1998). “Managing speed: Review of current practices for setting and enforcing speed limits.”, National Academy Press, Washington, DC.
Ugray, Z., Lasdon, L., Plummer, J., Glover, F., Kelly, J., and Marti, R. (2007). “Scatter search and local NLP solvers: A multistart framework for global optimization.” INFORMS J. Comput., 19(3), 328–340.
U.K. Highways Agency. (2004). “M25 controlled motorways.”, Highways Agency Publications Group, Bristol.
Ulfarsson, G. F., Shankar, V. N., and Vu, P. (2005). “The effect of variable message and speed limit signs on mean speeds and speed deviations.” Int. J. Veh. Inform. Commun. Syst., 1(1/2), 69–87.
van den Hoogen, E., and Smulders, S. (1994). “Control by variable speed signs. Results of the Dutch experiment.” 7th Int. Conf. on Road Traffic Monitoring and Control, IET, London, 145–149.
Weikl, S., Bogenberger, K., and Bertini, R. L. (2013). “Empirical assessment of traffic management effects of a variable speed limit system on a German Autobahn: Before and after.” TRB 92nd Annual Meeting Compendium of Papers (CD-ROM), Transportation Research Board of the National Academies, Washington, DC.
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Published In
Journal of Transportation Engineering
Volume 141 • Issue 12 • December 2015
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Mar 14, 2014
Accepted: May 21, 2015
Published online: Jul 31, 2015
Published in print: Dec 1, 2015
Discussion open until: Dec 31, 2015
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