Journal of Jilin University(Engineering and Technology Edition) ›› 2026, Vol. 56 ›› Issue (10): 2626-2634.doi: 10.13229/j.cnki.jdxbgxb.20250496

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Coupling effect of speed and road slope on emissions from light-duty vehicles

Yang YANG1,2(),Jia-xing HOU1,2,Qian YU3()   

  1. 1.School of Vehicle and Transportation Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China
    2.Smart Transportation Laboratory in Shanxi Province,Taiyuan 030024,China
    3.Key Laboratory of Transportation Industry for Control of Transportation Network Facilities and Recycling Restoration Technology in Ecological Security Barrier Area,Chang' an University,Xi'an 710064,China
  • Received:2025-06-05 Online:2026-10-01 Published:2026-10-09
  • Contact: Qian YU E-mail:2020015@tyust.edu.cn;yuqian@chd.edu.cn

Abstract:

Based on one-year, second-by-second on-board diagnostic(OBD) monitoring data from 10 light-duty vehicles in Xi'an, road slopes were extracted by combining high-resolution digital elevation models(DEMs) with geographic information system(GIS) path-matching techniques. Vehicle-specific power(VSP) theory and the Motor Vehicle Emission Simulator(MOVES) model were employed to estimate emissions of carbon monoxide(CO), hydrocarbons(HC), nitrogen oxides(NO x ), and particulate matter(PM). To address the limitations of conventional models in capturing the coupled effects of speed and slope, a bivariate polynomial regression model of speed-slope was developed, and an uphill-downhill partitioning strategy was applied to analyze the nonlinear characteristics of emissions. Results show that the proposed model achieves coefficient of determination(R2) values exceeding 0.82, with favorable error metrics. Specifically, emissions of all pollutants increase significantly with speed and slope under uphill conditions, whereas downhill operations exhibit generally lower emissions but with local peak values. Moreover, three-dimensional response surfaces indicate that HC and NO x are more sensitive to variations in operating conditions. This study provides a high-resolution quantification of the speed-slope-emission relationship, offering theoretical and empirical support for accurate urban micro-scale emission estimation, driving condition identification, and traffic-related emission reduction strategies.

Key words: vehicle operation engineering, light-duty vehicle emissions, speed-slope coupling, second-order polynomial regression, vehicle specific power

CLC Number: 

  • U491.9

Fig.1

Flow chart of vehicle trajectory and road slope calculation based on ArcGIS and DEM data"

Fig.2

Spatial distribution of field-sampled vehicletrajectories in Xi'an city"

Table 1

Fitting results under uphill and downhill segmentation"

坡度拟合参数污染物β0β1β2β3β4β5
上坡CO-8.136 2590.090 081-32.679 764-0.000 503294.788 9480.399 979
HC-10.674 8300.072 107-27.586 534-0.000 388270.228 2940.320 825
NO x-10.962 1250.083 527-31.634 116-0.000 462312.719 5880.363 534
PM-13.330 7390.077 097-27.085 290-0.000 418252.867 4150.333 062
下坡CO-8.256 2840.095 79221.229 739-0.000 556359.042 6990.028 730
HC-10.695 8860.073 38420.691 560-0.000 402308.620 937-0.049 474
NO x-11.419 0670.109 93925.057 602-0.000 765176.803 097-0.393 384
PM-13.396 7410.080 44518.380 008-0.000 450292.933 5630.001 800

Table 2

Performance evaluation metrics of prediction models for various pollutants"

坡度

评估指标

污染物

R2MSERMSEMAE
上坡CO0.857 30.002 3950.048 9380.004 019
HC0.872 35×10-60.002 2101.54×10-4
NO x0.859 85×10-60.002 2411.79×10-4
PM0.868 91×10-70.000 1811.4×10-6
下坡CO0.824 70.000 5950.024 4000.002 946
HC0.854 21×10-60.001 0001.06×10-4
NO x0.859 11×10-60.001 1131.30×10-4
PM0.843 51×10-70.000 0861×10-5

Table 3

Averaged performance metrics of pollutant prediction models via K-fold cross- validation"

坡度

评估指标

污染物

R2MSERMSEMAE
上坡CO0.842 80.002 3950.047 8530.004 019
HC0.852 25×10-60.002 0901.54×10-4
NO x0.845 05×10-60.002 1841.79×10-4
PM0.850 51×10-70.000 1741.4×10-6
下坡CO0.824 75.95×10-60.023 8390.002 946
HC0.854 11×10-60.000 9661.06×10-4
NO x0.827 91×10-60.001 0951.30×10-4
PM0.843 51×10-70.000 0831×10-5

Fig.3

Fitted surface of pollutant emissions varying with vehicle speed and road slope"

Table 4

Comparison of typical pollutant emission characteristics under different slope conditions"

污染物

运行

工况

峰值排放量/(g·s-1)

峰值速度/

(km·h-1)

峰值坡度/%
CO上坡0.029 5777.585
下坡0.015 880接近0
HC上坡0.001 7113.955
下坡0.000 6492.13接近0
NO x上坡0.002 1109.15
下坡0.000 7487.28接近0
PM上坡0.000 15111.535
下坡0.000 0689.71接近0
[1] Li R, Li L, Wang Q. The impact of energy efficiency on carbon emissions: evidence from the transportation sector in Chinese 30 Provinces[J]. Sustainable Cities and Society, 2022, 82: 103880.
[2] 陈坚, 陈嘉果, 陈琦, 等. 山地城市道路交通碳排放影响因素非线性关系模型[J]. 交通运输系统工程与信息, 2024, 24(5): 237-245.
Chen Jian, Chen Jia-guo, Chen Qi, et al. Nonlinear relationship model of factors influencing carbon emissions in mountainous urban road transportation[J]. Journal of Transportation Systems Engineering and Information Technology, 2024, 24(5): 237-245.
[3] 吕晨, 张哲, 陈徐梅, 等. 中国分省道路交通二氧化碳排放因子[J]. 中国环境科学, 2021, 41(7): 3122-3130.
Lv Chen, Zhang Zhe, Chen Xu-mei, et al. Study on CO2 emissiom factors of road transport in Chinese provinces[J]. China Environmental Science, 2021, 41(7): 3122-3130.
[4] Li Y, Lü C, Yang N, et al. A study of high temporal-spatial resolution greenhouse gas emissions inventory for on-road vehicles based on traffic speed-flow model: a case of Beijing[J]. Journal of Cleaner Production, 2020, 277: 122419.
[5] 靳秋思, 张远景, 宋国华, 等.基于交通运行指数的速度分布聚类与排放测算[J]. 交通信息与安全, 2016, 34(6): 15-21, 76.
Jin Qiu-si, Zhang Yuan-jing, Song Guo-hua, et al. A clustering analysis of speed distributions and emission estimation based on traffic performance index[J]. Journal of Transport Information and Safety, 2016, 34(6): 15-21, 76.
[6] 姜壁刚, 何超, 王艳艳, 等. 道路坡度对轻型柴油车二氧化碳排放的影响[J]. 公路交通科技, 2025, 42(2): 207-214.
Jiang Bi-gang, He Chao, Wang Yan-yan, et al. Influence of road gradient on CO2 emission from light-duty diesel vehicles[J]. Journal of Highway and Transportation Research and Development, 2025, 42(2): 207-214.
[7] 周涛, 李毅军, 孙琴梅, 等. 大数据驱动下的山地城市道路条件对车辆碳排放影响研究[J]. 交通运输系统工程与信息, 2023, 23(5): 172-183.
Zhou Tao, Li Yi-jun, Sun Qin-mei, et al. Impact of mountain urban roads on vehicle carbon emissions driven by big data[J]. Journal of Transportation Systems Engineering and Information Technology, 2023, 23(5): 172-183.
[8] Wang Y, Feng X, Zhao H, et al. Experimental study of CO2 and pollutant emission at various altitudes: Inconsistent results and reason analysis[J]. Fuel, 2022, 307: 121801.
[9] Dong Y, Xu J, Gu C. Modelling carbon emissions of diesel trucks on longitudinal slope sections in China[J]. Plos One, 2020, 15(6): e0234789.
[10] Sentoff K M, Aultman-Hall L, Holmén B A. Implications of driving style and road grade for accurate vehicle activity data and emissions estimates[J]. Transportation Research Part D: Transport and Environment, 2015, 35: 175-188.
[11] Liu H, Rodgers M O, Guensler R. Impact of road grade on vehicle speed-acceleration distribution, emissions and dispersion modeling on freeways[J]. Transportation Research Part D: Transport and Environment, 2019, 69: 107-122.
[12] 孙振华, 许金良, 徐贵龙, 等. 基于MOVES的上坡路段载重车碳排放规律研究[J]. 公路, 2021, 66(3): 328-336.
Sun Zhen-hua, Xu Jin-liang, Xu Gui-long, et al. Research on carbon emission law of truck on uphill section based on MOVES[J]. Highway, 2021, 66(3): 328-336.
[13] 郑春燕, 张海, 郭栋, 等. 城市道路坡度和车速对机动车排放的影响[J]. 河南科技大学学报: 自然科学版, 2019, 40(2): 35-39, 44,6.
Zheng Chun-yan, Zhang Hai, Guo Dong, et al. Effects of urban road slope and vehicle speed on vehicle emissions[J]. Journal of Henan University of Science and Technology(Natural Science), 2019, 40(2): 35-39, 44, 6.
[14] . 机动车运行安全技术条件 [S]. 北京:中国标准出版社,2017.
[15] Ilyas Ihab F, Chu Xu. Data Cleaning[M]. London: Macmillan, 2019.
[16] 周启鸣, 刘学军. 数字地形分析[M]. 北京: 科学出版社, 2006.
[17] environment protection agency US.MOVES2014a software design reference manual[EB/OL]. [2025-06-01]. .
[18] environment protection agency US. Exhaust emission rates for light-duty on-road vehicles in MOVES2014[EB/OL]. [2025-06-01]. .
[19] 陈兴辉, 刘皓冰, 胡兴华. 考虑混动车NO x 排放工况影响的交叉口信号配时优化模型[J]. 吉林大学学报: 工学版, 2026, 56(8): 2137-2149.
Chen Xing-hui, Liu Hao-bing, Hu Xing-hua. Intersection signal timing optimization model considering influence of hybrid vehicles NO x emission conditions[J]. Journal of Jilin University(Engineering and Technology Edition), 2026, 56(8): 2137-2149.
[20] Jimenez-Palacios J L. Understanding and quantifying motor vehicle emissions with vehicle specific power and TILDAS remote sensing[D]. Cambridge: Massachusetts Institute of Technology, 1998.
[21] Sentoff K M, Aultman-Hall L, Holmén B A. Implications of driving style and road grade for accurate vehicle activity data and emissions estimates[J]. Transportation Research Part D: Transport and Environment, 2015, 35: 175-188.
[22] 姚荣涵, 龙梦, 赵胜川. 基于正交试验的信号交叉口机动车排放影响因素分析[J]. 北京工业大学学报, 2020, 46(3): 300-310.
Yao Rong-han, Long Meng, Zhao Sheng-chuan. Influencing factor analysis of vehicle emissions at signalized intersection based on oethogonal experiments[J]. Journal of Beijing University of Technology, 2020, 46(3): 300-310.
[23] 王江锋, 贺丹, 罗冬宇, 等. 基于交互信息融合网络的车辆行驶风险预测模型[J]. 吉林大学学报: 工学版, 2026, 56(8): 2177-2190.
Wang Jiang-feng, He Dan, Luo Dong-yu, et al. Vehicle traveling risk prediction based on interactive information fusion network[J]. Journal of Jilin University(Engineering and Technology Edition), 2026, 56(8): 2177-2190.
[24] Arlot S, Celisse A. A survey of cross-validation procedures for model selection[J]. Statistics Surveys, 2010, 4: 40-79.
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