On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models

In traffic flow, the relationship between speed and density exhibits decreasing monotonicity and continuity, which is characterized by various models such as the Greenshields and Greenberg models. However, some existing models, i.e., the Underwood and Northwestern models, introduce bias by incorrect...

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Main Authors: Yidan Shangguan, Xuecheng Tian, Sheng Jin, Kun Gao, Xiaosong Hu, Wen Yi, Yu Guo, Shuaian Wang
Format: Article
Language:English
Published: MDPI AG 2023-08-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/11/16/3460
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author Yidan Shangguan
Xuecheng Tian
Sheng Jin
Kun Gao
Xiaosong Hu
Wen Yi
Yu Guo
Shuaian Wang
author_facet Yidan Shangguan
Xuecheng Tian
Sheng Jin
Kun Gao
Xiaosong Hu
Wen Yi
Yu Guo
Shuaian Wang
author_sort Yidan Shangguan
collection DOAJ
description In traffic flow, the relationship between speed and density exhibits decreasing monotonicity and continuity, which is characterized by various models such as the Greenshields and Greenberg models. However, some existing models, i.e., the Underwood and Northwestern models, introduce bias by incorrectly utilizing linear regression for parameter calibration. Furthermore, the lower bound of the fitting errors for all these models remains unknown. To address above issues, this study first proves the bias associated with using linear regression in handling the Underwood and Northwestern models and corrects it, resulting in a significantly lower mean squared error (MSE). Second, a quadratic programming model is developed to obtain the lower bound of the MSE for these existing models. The relative gaps between the MSEs of existing models and the lower bound indicate that the existing models still have a lot of potential for improvement.
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spelling doaj.art-906f901d0bf248d884158d6c0577cf852023-11-19T02:02:18ZengMDPI AGMathematics2227-73902023-08-011116346010.3390/math11163460On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression ModelsYidan Shangguan0Xuecheng Tian1Sheng Jin2Kun Gao3Xiaosong Hu4Wen Yi5Yu Guo6Shuaian Wang7Department of Logistics and Maritime Studies, Faculty of Business, The Hong Kong Polytechnic University, Hung Hom, Hong KongDepartment of Logistics and Maritime Studies, Faculty of Business, The Hong Kong Polytechnic University, Hung Hom, Hong KongCollege of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, ChinaDepartment of Architecture and Civil Engineering, Chalmers University of Technology, 412 96 Göteborg, SwedenState Key Laboratory of Mechanical Transmission/Automotive Collaborative Innovation Center, Chongqing University, Chongqing 400044, ChinaDepartment of Building and Real Estate, The Hong Kong Polytechnic University, Hung Hom, Hong KongDepartment of Logistics and Maritime Studies, Faculty of Business, The Hong Kong Polytechnic University, Hung Hom, Hong KongDepartment of Logistics and Maritime Studies, Faculty of Business, The Hong Kong Polytechnic University, Hung Hom, Hong KongIn traffic flow, the relationship between speed and density exhibits decreasing monotonicity and continuity, which is characterized by various models such as the Greenshields and Greenberg models. However, some existing models, i.e., the Underwood and Northwestern models, introduce bias by incorrectly utilizing linear regression for parameter calibration. Furthermore, the lower bound of the fitting errors for all these models remains unknown. To address above issues, this study first proves the bias associated with using linear regression in handling the Underwood and Northwestern models and corrects it, resulting in a significantly lower mean squared error (MSE). Second, a quadratic programming model is developed to obtain the lower bound of the MSE for these existing models. The relative gaps between the MSEs of existing models and the lower bound indicate that the existing models still have a lot of potential for improvement.https://www.mdpi.com/2227-7390/11/16/3460speed and density relationshiplinear regressionquadratic programming
spellingShingle Yidan Shangguan
Xuecheng Tian
Sheng Jin
Kun Gao
Xiaosong Hu
Wen Yi
Yu Guo
Shuaian Wang
On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models
Mathematics
speed and density relationship
linear regression
quadratic programming
title On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models
title_full On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models
title_fullStr On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models
title_full_unstemmed On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models
title_short On the Fundamental Diagram for Freeway Traffic: Exploring the Lower Bound of the Fitting Error and Correcting the Generalized Linear Regression Models
title_sort on the fundamental diagram for freeway traffic exploring the lower bound of the fitting error and correcting the generalized linear regression models
topic speed and density relationship
linear regression
quadratic programming
url https://www.mdpi.com/2227-7390/11/16/3460
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