{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:14:47Z","timestamp":1760242487746,"version":"build-2065373602"},"reference-count":22,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2017,8,3]],"date-time":"2017-08-03T00:00:00Z","timestamp":1501718400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Information"],"abstract":"<jats:p>In order to estimate traffic densities in a large-scale urban freeway network in an accurate and timely fashion when traffic sensors do not cover the freeway network completely and thus only local measurement data can be utilized, this paper proposes a decentralized state observer approach based on a macroscopic traffic flow model. Firstly, by using the well-known cell transmission model (CTM), the urban freeway network is modeled in the way of distributed systems. Secondly, based on the model, a decentralized observer is designed. With the help of the Lyapunov function and S-procedure theory, the observer gains are computed by using linear matrix inequality (LMI) technique. So, the traffic densities of the whole road network can be estimated by the designed observer. Finally, this method is applied to the outer ring of the Beijing\u2019s second ring road and experimental results demonstrate the effectiveness and applicability of the proposed approach.<\/jats:p>","DOI":"10.3390\/info8030095","type":"journal-article","created":{"date-parts":[[2017,8,3]],"date-time":"2017-08-03T09:47:19Z","timestamp":1501753639000},"page":"95","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Decentralized State-Observer-Based Traffic Density Estimation of Large-Scale Urban Freeway Network by Dynamic Model"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3834-754X","authenticated-orcid":false,"given":"Yuqi","family":"Guo","sequence":"first","affiliation":[{"name":"College of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, China"},{"name":"Beijing Key Laboratory of Transportation Engineering, Beijing 100124, China"},{"name":"Beijing Collaborative Innovation Center for Metropolitan Transportation, Beijing 100124, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yangzhou","family":"Chen","sequence":"additional","affiliation":[{"name":"College of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, China"},{"name":"Beijing Key Laboratory of Transportation Engineering, Beijing 100124, China"},{"name":"Beijing Collaborative Innovation Center for Metropolitan Transportation, Beijing 100124, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chiyuan","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, China"},{"name":"Beijing Key Laboratory of Transportation Engineering, Beijing 100124, China"},{"name":"Beijing Collaborative Innovation Center for Metropolitan Transportation, Beijing 100124, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,8,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/0191-2615(94)90002-7","article-title":"The cell transmission model: A dynamic representation of highway traffic consistent with the hydrodynamic theory","volume":"28","author":"Daganzo","year":"1994","journal-title":"Transp. Res. Part B"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/0191-2615(94)00022-R","article-title":"The cell transmission model, part II: Network traffic","volume":"29","author":"Daganzo","year":"1995","journal-title":"Transp. Res. Part B"},{"key":"ref_3","unstructured":"Mu\u00f1oz, L., Sun, X., Horowitz, R., and Luis, A. (2003, January 4\u20136). Traffic density estimation with the cell transmission model. Proceedings of the American Control Conference (ACC), Denver, CO, USA."},{"key":"ref_4","unstructured":"Mu\u00f1oz, L., Sun, X., Sun, D., Gomes, G., and Horowitz, R. (July, January 30). Methodological calibration of the cell transmission model. Proceedings of the IEEE American Control Conference (ACC), Boston, MA, USA."},{"key":"ref_5","unstructured":"Alvarez-Icaza, L., Mu\u00f1oz, L., Sun, X., and Horowitz, R. (July, January 30). Adaptive observer for traffic density estimation. 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