Estimation Method of Equivalent Units for Entering Vehicles at Highways' Accesses

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Abstract Equivalent units of vehicles are important parameters for road capacity and service level analysis. However, due to the fact that our country's existing road network has not yet included access roads into the technical grade system and lacks corresponding design specifications and technical standards, access points often have great impacts on highway traffic operations. Based on the characteristics of different types of vehicles at the highway entrance, this paper analyzes the physical significance of occupying space-time resources of lanes on the highway section under different traffic flow statuses when the vehicle at the access point enters the highway section. Furthermore, taking the passenger car as the standard vehicle, estimation models for equivalent units of vehicles at the highway and the access point are proposed respectively. Finally, the UAV aerial photography is used to collect field data, and an access point on Zhengzhou G107 with multiple vehicle types is used as an example for empirical analysis. Calculation results show that:(1) At the access point, the equivalent unit of each entering vehicle type increases with the increase of road traffic; and the more lanes occupied during the entry process, the higher the vehicle equivalent unit. (2) At the access point, the equivalent unit of each vehicle type increases first and then decreases with the increase of the traffic flow speed on the highway section, which shows a boundary around 40km/h. That is because, in the steady flow state between the free flow and the saturated flow, the headway is between that of the free flow and that of the saturated flow. The vehicle at the access point is more convenient when driving into the highway section, but it affects many vehicles on the road highway. At this time, the vehicle equivalent unit is also large.

Key words： traffic engineering vehicle equivalent unit space-time source urbanized highway access point

Received: 03 August 2021

Fund:Supported by the National Natural Science Foundation of China (No.51678535); Foundation for University Young Key Teacher by Henan Province (No. 2018GGJS004)

Corresponding Authors: YAN Ya-dan E-mail: yanyadan@zzu.edu.cn

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	YAN Ya-dan
	ZHAO Peng
	TONG Pei
	WANG Dong-wei

Cite this article:

YAN Ya-dan,ZHAO Peng,TONG Pei, et al. Estimation Method of Equivalent Units for Entering Vehicles at Highways' Accesses[J]. Journal of Highway and Transportation Research and Development, 2021, 15(3): 73-82.

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http://journal10.magtechjournal.com/Jwk_gljtkj_en/EN/ OR http://journal10.magtechjournal.com/Jwk_gljtkj_en/EN/Y2021/V15/I3/73

[1] RAJ P, SIVAGNANASUNDARAM K, ASAITHAMBI G, et al. Review of Methods for Estimation of Passenger Car Unit Values of Vehicles[J]. Journal of Transportation Engineering, 2019, 145(6):04019019.
[2] MONDAL S, CHAKRABORTY S, ROY S K, et al. Estimation of Passenger Car Unit for Heterogeneous Traffic Stream of Urban Arterials:Case Study of Kolkata[J/OL]. (2017-01-13)[2017-02-20]. https://doi.org/10.1080/19427867.2017.1293313.
[3] DHAMANIYA A, CHANDRA S. Conceptual Approach for Estimating Dynamic Passenger Car Units on Urban Arterial Roads by Using Simultaneous Equations[J]. Transportation Research Record, 2016, 2553:108-116.
[4] RAJ P, SHAHANA A, ASAITHAMBI G, et al. An Approach for Estimation of Passenger Car Unit Values of Vehicles Based on Influence of Neighboring Vehicles[C]//Proceedings of the 97th Transportation Research Board Annual Meeting. Washington, D.C. Transportation Research Board, 2018.
[5] YEUNG J S, WONG Y D, SECADININGRAT J R. Lane-harmonised Passenger Car Equivalents for Heterogeneous Expressway Traffic[J]. Transportation Research Part A:Policy and Practice, 2015, 78:361-370.
[6] XUE X J, SHI F, CHEN Q. Capacity Estimation for On-ramp Merging Section of Urban Expressway Based on Time Headway Loss[J]. Discrete Dynamics in Nature and Society, 2014, 1776:1-9.
[7] TIWARI G, FAZIO J, PAVITRAVAS S. Passenger Car Units for Heterogeneous Traffic Using A Modified Density Method[C]//Proceedings of the 4th International Symposium on Highway Capacity. Washington, D.C.:Transportation Research Board, 2000.
[8] BENEKOHAL R F, ZHAO W X. Delay-based Passenger Car Equivalents for Trucks at Signalized Intersections[J]. Transportation Research Part A:Policy and Practice, 2000, 34(6):437-457.
[9] RADHAKRISHNAN P, MATHEW T V. Passenger Car Units and Saturation Flow Models for Highly Heterogeneous Traffic at Urban Signalized Intersections[J]. Transportmetrica, 2011, 7(2):141-162.
[10] MOHAN M, CHANDRA S. Three Methods of PCU Estimation at Unsignalized Intersections[J]. Trans-portation Letters, 2018, 10(2):68-74.
[11] GIUFFRō O, GRANÀ A, TUMMINELLO M L, et al. Capacity-based Calculation of Passenger Car Equivalents Using Traffic Simulation at Double-lane Roundabouts[J]. Simulation Modelling Practice and Theory, 2018, 81:11-30.
[12] XUE Xing-jian. Research of Vehicle Conversion Coefficients on Urban Expressway Ramp at Merging Area[J]. Journal of Chongqing Jiaotong University:Natural Science Edition, 2015, 34(1):95-99. (in Chinese)
[13] LI Hong-wei, LU Jian. An Algorithm of Passenger Car Equivalent for Urban Road Sections Based on Mean Time Headway[J]. Journal of Transport Information and Safety, 2018, 36(3):79-83, 111. (in Chinese)
[14] FU Qiang, LIN Hang-fei, YANG Xiao-fang, et al. Passenger Car Equivalence Research out of Level of Service Consideration[J]. Journal of Tongji University:Natural Science Edition, 2007, 35(1):67-71. (in Chinese)
[15] AO Gu-chang, JIA Yuan-hua, ZHANG Hui-ling. Vehicle Conversion Factors Based on the Analysis of Occupancy Time[J]. Journal of Transportation Systems Engineering and Information Technology, 2008, 8(3):106-110. (in Chinese)
[16] SUN Shan, LI Wen-quan, BAI Hai-jian. Passenger Car Equivalence in Freeway Merging Area[J]. Journal of Transport Information and Safety, 2010, 28(1):54-58. (in Chinese)
[17] QU Da-yi, YANG Jian, CHEN Xiu-feng, et al. Method of Dynamic Vehicle Conversion Factors Based on Traffic Flow Characteristic Analysis[J]. Journal of Highway and Transportation Research and Development, 2012, 29(4):132-136. (in Chinese)
[18] XU Jian-min, YAN Xiao-wen, MA Ying-ying. Effects of Mixed Traffic Flow on Macroscopic Fundamental Diagrams and Its Application to Analysis of Passenger Car Equivalent[J]. China Journal of Highway and Transport, 2018, 31(8):145-154. (in Chinese)
[19] GUO Xiu-cheng, LU Guang-ming, RAN Jiang-yu, et al. A Study on Minimum Access Spacing of First Grade Highway[J]. Highway, 2007(12):12-16. (in Chinese)
[20] METKARI M, BUDHKAR A K, MAURYA A K. Review of Passenger Car Equivalence Studies in Indian Context[J]. International Journal of Computer Applications, 2012(5):19-23.
[21] LARRAGA M E, ALVAREZ-ICAZA L. Cellular Automaton Model for Traffic Flow Based on Safe Driving Policies and Human Reactions[J]. Physica A:Statistical Mechanics and Its Applications, 2010, 389(23):5425-5438.
[22] TIAN J, LI G, TREIBER M, et al. Cellular Automaton Model Simulating Spatiotemporal Patterns, Phase Transitions and Concave Growth Pattern of Oscillations in Traffic Flow[J]. Transportation Research Part B:Methodological, 2016, 93:560-575.
[23] YU S, SHI Z. An Improved Car-following Model Considering Relative Velocity Fluctuation[J]. Communications in Nonlinear Science and Numerical Simulation, 2016, 36:319-326.
[24] WANG Xiao-ning, WU Zhi-tao. Research of Speed-volume Relationship of Expressway Straight Section in Low-density Area[J]. Journal of Highway and Transportation Research and Development, 2014, 31(11):130-136. (in Chinese)
[25] SUN Yu-xing, CHEN De-wang, WU Jian-ping. Research on Traffic Stream Speed-Density Model of Beijing Urban Expressway[J]. Journal of Beijing Jiaotong University, 2004, 28(6):70-73. (in Chinese)