Communications - Scientific letters of the University of Zilina X:X | DOI: 10.26552/com.C.2026.054
Stopped Fraction and Closure Failure in Congested Macroscopic Fundamental Diagrams: A Sumo-Based Simulation Study
- Waseda University, School of Social Sciences, Tokyo, Japan
Congested macroscopic fundamental diagrams (MFDs) often display scatter since accumulation alone does not fully describe immobilization within stored traffic. In this paper, the stopped fraction, defined as the share of vehicles that are stopped or nearly stopped, is examined as a complementary macroscopic state variable. A compact analytical framework shows why accumulation-only closure can fail when stopped fraction varies at fixed accumulation. The mechanism is tested using the Simulation of Urban MObility (SUMO) platform on a stylized signalized grid. Adding stopped fraction reduces the root mean squared error (RMSE) from 41.32 to 18.79 overall, and from 55.84 to 23.40 in the congested regime, where R² rises from 0.8777 to 0.9785. Stopped fraction therefore provides a practical diagnostic for congestion states omitted from accumulation-only MFD representations.
Keywords: macroscopic fundamental diagram, stopped fraction, SUMO simulation, congested traffic, closure failure, network production
Grants and funding:
The author gratefully acknowledges helpful discussions from colleagues. Any remaining errors are solely the author’s responsibility.
Conflicts of interest:
The author declares that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Received: May 13, 2026; Accepted: September 2, 2026; Prepublished online: September 17, 2026
References
- DAGANZO, C. F. Urban gridlock: macroscopic modeling and mitigation approaches. Transportation Research Part B: Methodological [online]. 2007, 41(1), p. 49-62 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2006.03.001
Go to original source... - GEROLIMINIS, N., DAGANZO, C. F. Existence of urban-scale macroscopic fundamental diagrams: some experimental findings. Transportation Research Part B: Methodological [online]. 2008, 42(9), p. 759-770 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2008.02.002
Go to original source... - DAGANZO, C. F., GEROLIMINIS, N. An analytical approximation for the macroscopic fundamental diagram of urban traffic. Transportation Research Part B: Methodological [online]. 2008, 42(9), p. 771-781 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2008.06.008
Go to original source... - ZHANG, L., YUAN, Z., YANG, L., LIU, Z. Recent developments in traffic flow modeling using macroscopic fundamental diagram. Transport Reviews [online]. 2020, 40(4), p. 529-550 [accessed 2026-08-21]. ISSN 0144-1647, eISSN 1464-5327. Available from: https://doi.org/10.1080/01441647.2020.1743918
Go to original source... - MAZLOUMIAN, A., GEROLIMINIS, N., HELBING, D. The spatial variability of vehicle densities as determinant of urban network capacity. Philosophical Transactions of the Royal Society A [online]. 2010, 368(1928), p. 4627-4647 [accessed 2026-08-21]. eISSN 1364-503X. Available from: https://doi.org/10.1098/rsta.2010.0099
Go to original source... - GAYAH, V. V., DAGANZO, C. F. Clockwise hysteresis loops in the macroscopic fundamental diagram: an effect of network instability. Transportation Research Part B: Methodological [online]. 2011, 45(4), p. 643-655 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2010.11.006
Go to original source... - GEROLIMINIS, N., BOYACI, B. The effect of variability of urban systems characteristics in the network capacity. Transportation Research Part B: Methodological [online]. 2012, 46(10), p. 1607-1623 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2012.08.001
Go to original source... - GAYAH, V. V., GAO, X., NAGLE, A. S. On the impacts of locally adaptive signal control on urban network stability and the macroscopic fundamental diagram. Transportation Research Part B: Methodological [online]. 2014, 70, p. 255-268 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2014.09.010
Go to original source... - RAMEZANI, M., HADDAD, J., GEROLIMINIS, N. Dynamics of heterogeneity in urban networks: aggregated traffic modeling and hierarchical control. Transportation Research Part B: Methodological [online]. 2015, 74, p. 1-19 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2014.12.010
Go to original source... - ALVAREZ LOPEZ, P., BEHRISCH, M., BIEKER-WALZ, L., ERDMANN, J., FLOTTEROD, Y.-P., HILBRICH, R., LUCKEN, L., RUMMEL, J., WAGNER, P., WIESSNER, E. Microscopic traffic simulation using SUMO. In: 2018 21st International Conference on Intelligent Transportation Systems (ITSC): proceedings [online]. IEEE. 2018. ISBN 978-1-7281-0321-1, eISBN 978-1-7281-0323-5, eISSN 2153-0017, p. 2575-2582 [accessed 2026-08-21]. Available from: https://doi.org/10.1109/ITSC.2018.8569938
Go to original source... - KEYVAN-EKBATANI, M., KOUVELAS, A., PAPAMICHAIL, I., PAPAGEORGIOU, M. Exploiting the fundamental diagram of urban networks for feedback-based gating. Transportation Research Part B: Methodological [online]. 2012, 46(10), p. 1393-1403 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2012.06.008
Go to original source... - TILG, G., AMINI, S., BUSCH, F. Evaluation of analytical approximation methods for the macroscopic fundamental diagram. Transportation Research Part C: Emerging Technologies [online]. 2020, 114, p. 1-19 [accessed 2026-08-21]. ISSN 0968-090X, eISSN 1879-2359. Available from: https://doi.org/10.1016/j.trc.2020.02.003
Go to original source... - HERMAN, R., PRIGOGINE, I. A two-fluid approach to town traffic. Science [online]. 1979, 204(4389), p. 148-151 [accessed 2026-08-21]. ISSN 0036-8075, eISSN 1095-9203. Available from: https://doi.org/10.1126/science.204.4389.148
Go to original source... - KNOOP, V. L., VAN LINT, H., HOOGENDOORN, S. P. Traffic dynamics: its impact on the macroscopic fundamental diagram. Physica A: Statistical Mechanics and its Applications [online]. 2015, 438, p. 236-250 [accessed 2026-08-21]. ISSN 0378-4371, eISSN 1873-2119. Available from: https://doi.org/10.1016/j.physa.2015.06.016
Go to original source... - JI, Y., GEROLIMINIS, N. On the spatial partitioning of urban transportation networks. Transportation Research Part B: Methodological [online]. 2012, 46(10), p. 1639-1656 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2012.08.005
Go to original source... - XU, G., YU, Z., GAYAH, V. V. Analytical method to approximate the impact of turning on the macroscopic fundamental diagram. Transportation Research Record: Journal of the Transportation Research Board [online]. 2020, 2674(9), p. 933-947 [accessed 2026-08-21]. ISSN 0361-1981, eISSN 2169-4052. Available from: https://doi.org/10.1177/0361198120933274
Go to original source... - POSTRANSKYY, T., BOIKIV, M., AFONIN, M., MOHYLA, I. Influence of traffic flow parameters on the delay duration at signalized intersections. Communications - Scientific Letters of the University of Zilina [online]. 2026, 28(1), p. D13-D26 [accessed 2026-08-21]. ISSN 1335-4205, eISSN 2585-7878. Available from: https://doi.org/10.26552/com.C.2026.004
Go to original source... - GEROLIMINIS, N., ZHENG, N., AMPOUNTOLAS, K. A three-dimensional macroscopic fundamental diagram for mixed bi-modal urban networks. Transportation Research Part C: Emerging Technologies [online]. 2014, 42, p. 168-181 [accessed 2026-08-21]. ISSN 0968-090X, eISSN 1879-2359. Available from: https://doi.org/10.1016/j.trc.2014.03.004
Go to original source... - LODER, A., AMBUHL, L., MENENDEZ, M., AXHAUSEN, K. W. Empirics of multi-modal traffic networks using the 3D macroscopic fundamental diagram. Transportation Research Part C: Emerging Technologies [online]. 2017, 82, p. 88-101 [accessed 2026-08-21]. ISSN 0968-090X, eISSN 1879-2359. Available from: https://doi.org/10.1016/j.trc.2017.06.009
Go to original source... - AMPOUNTOLAS, K., ZHENG, N., GEROLIMINIS, N. Macroscopic modelling and robust control of bi-modal multi-region urban road networks. Transportation Research Part B: Methodological [online]. 2017, 104, p. 616-637 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2017.05.007
Go to original source... - LODER, A., AMBUHL, L., MENENDEZ, M., AXHAUSEN, K. W. Understanding traffic capacity of urban networks. Scientific Reports [online]. 2019, 9, 16283 [accessed 2026-08-21]. eISSN 2045-2322. Available from: https://doi.org/10.1038/s41598-019-51539-5
Go to original source... - AMBUHL, L., LODER, A., BLIEMER, M. C. J., MENENDEZ, M., AXHAUSEN, K. W. A functional form with a physical meaning for the macroscopic fundamental diagram. Transportation Research Part B: Methodological [online]. 2020, 137, p. 119-132 [accessed 2026-08-21]. ISSN 0191-2615, eISSN 1879-2367. Available from: https://doi.org/10.1016/j.trb.2018.10.013
Go to original source... - HAN, K., HUANG, T., FAN, W., GE, Q., DONG, S., WANG, X. Macroscopic fundamental diagram with volume-delay relationship: model derivation, empirical validation and invariance property. Transportation Research Part C: Emerging Technologies [online]. 2024, 166, 104739 [accessed 2026-08-21]. ISSN 0968-090X, eISSN 1879-2359. Available from: https://doi.org/10.1016/j.trc.2024.104739
Go to original source... - MAITI, N., SEPPECHER, M., LECLERCQ, L. Challenges in calibrating multimodal network macroscopic fundamental diagrams: a review and definition of data fusion pipeline. European Transport Research Review [online]. 2025, 17, 51 [accessed 2026-08-21]. eISSN 1866-8887. Available from: https://doi.org/10.1186/s12544-025-00750-9
Go to original source... - BARMPOUNAKIS, E., GEROLIMINIS, N. On the new era of urban traffic monitoring with massive drone data: the pNEUMA large-scale field experiment. Transportation Research Part C: Emerging Technologies [online]. 2020, 111, p. 50-71 [accessed 2026-08-21]. ISSN 0968-090X, eISSN 1879-2359. Available from: https://doi.org/10.1016/j.trc.2019.11.023
Go to original source... - PAIPURI, M., BARMPOUNAKIS, E., GEROLIMINIS, N., LECLERCQ, L. Empirical observations of multi-modal network-level models: insights from the pNEUMA experiment. Transportation Research Part C: Emerging Technologies [online]. 2021, 131, 103300 [accessed 2026-08-21]. ISSN 0968-090X, eISSN 1879-2359. Available from: https://doi.org/10.1016/j.trc.2021.103300
Go to original source... - BARMPOUNAKIS, E., MONTESINOS-FERRER, M., GONZALES, E. J., GEROLIMINIS, N. Empirical investigation of the emission-macroscopic fundamental diagram. Transportation Research Part D: Transport and Environment [online]. 2021, 101, 103090 [accessed 2026-08-21]. ISSN 1361-9209, eISSN 1879-2340. Available from: https://doi.org/10.1016/j.trd.2021.103090
Go to original source... - BAZA-SOLARES, N., VELASQUEZ-MARTINEZ, R., TORRES-BOHORQUEZ, C., MARTINEZ-ESTUPINAN, Y., POLIZIANI, C. Traffic simulation with open-source and commercial traffic microsimulators: a case study. Communications - Scientific Letters of the University of Zilina [online]. 2022, 24(2), p. E49-E62 [accessed 2026-08-21]. ISSN 1335-4205, eISSN 2585-7878. Available from: https://doi.org/10.26552/com.C.2022.2.E49-E62
Go to original source...
This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, distribution, and reproduction in any medium, provided the original publication is properly cited. No use, distribution or reproduction is permitted which does not comply with these terms.

ORCID...