Research on truck gear selection and speed characteristics on extended longitudinal gradients on mountainous expressways

doi:10.3969/j.issn.1674-8484.2026.03.005

Abstract

Abstract:

A questionnaire survey was conducted among nearly one hundred truck drivers with certain driving experience, collecting gear selection decisions and speed choices of trucks to investigate the driving habits and the driving characteristics of truck drivers on long and steep longitudinal gradients on mountainous expressways to improve safety levels on such roads. The results show that the trucks with more axles use higher gears on long uphill sections when fully loaded; the truck drivers use higher gears as the number of axles increases on long downhill sections. The truck drivers use higher gears and speeds on downhill than on uphill. When empty, truck drivers use higher gears and speeds than when fully loaded. The drivers use higher gears and speeds on gentler gradients than on steeper gradients. The speeds of three-axle and four-axle trucks are higher, while those of five-axle and six-axle trucks are lowest. Moreover, the truck’s speed increases when descending a slope compared to ascending it. The findings of this study provide a theoretical basis for optimizing safety management protocols and operational strategies for extended longitudinal gradients on mountainous expressways.

Key words: traffic engineering, driving behavior, questionnaire, number of axles, speed characteristics

CLC Number:

U491

WU Kaixiang, WANG Rui, DUAN Weijian, XU Jin, LIU Ying. Research on truck gear selection and speed characteristics on extended longitudinal gradients on mountainous expressways[J]. Journal of Automotive Safety and Energy, 2026, 17(3): 332-341.

Figures/Tables 10

References 21

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驾驶情况	两轴货车		三轴货车		四轴货车		五、六轴货车
驾驶情况	上坡	下坡	上坡	下坡	上坡	下坡	上坡	下坡
满载缓坡	5.14	5.83	6.48	6.97	8.33	9.58	8.81	9.86
空载缓坡	6.00	6.43	6.81	6.96	11.33	10.89	10.29	12.00
满载陡坡	3.67	5.29	5.04	6.32	6.58	8.80	8.00	10.00
空载陡坡	5.09	5.76	6.26	6.36	10.11	9.89	6.50	10.00

驾驶情况	两轴货车		三轴货车		四轴货车		五、六轴货车
驾驶情况	上坡	下坡	上坡	下坡	上坡	下坡	上坡	下坡
满载缓坡	5.14	5.83	6.48	6.97	8.33	9.58	8.81	9.86
空载缓坡	6.00	6.43	6.81	6.96	11.33	10.89	10.29	12.00
满载陡坡	3.67	5.29	5.04	6.32	6.58	8.80	8.00	10.00
空载陡坡	5.09	5.76	6.26	6.36	10.11	9.89	6.50	10.00

货车类型	比功率/ (kW·t^-1)
货车类型	P50	P85	均值
两轴货车	9.78	12.09	10.00
三轴货车	9.52	11.32	9.47
四轴货车	8.90	11.00	9.21
五轴货车	6.42	7.06	6.43
六轴货车	6.93	8.29	7.14

货车类型	比功率/ (kW·t^-1)
货车类型	P50	P85	均值
两轴货车	9.78	12.09	10.00
三轴货车	9.52	11.32	9.47
四轴货车	8.90	11.00	9.21
五轴货车	6.42	7.06	6.43
六轴货车	6.93	8.29	7.14

货车类别	驾驶情况	均值 (km·h^-1)	最小值 (km·h^-1)	中位数 (km·h^-1)	最大值 (km·h^-1)	P50 (km·h^-1)	P85 (km·h^-1)	标准差 (km·h^-1)	显著性
两轴货车	满载缓坡	51.32	30	50	70	40	68	11.91
	空载缓坡	57.14	20	60	90	40	75	18.27
	满载陡坡	34.28	15	30	60	20	45	11.43
	空载陡坡	46.75	15	50	80	30	65	17.86
三轴货车	满载缓坡	57.29	20	60	80	30	70	16.01	0.001
	空载缓坡	57.33	20	60	85	30	80	17.85
	满载陡坡	42.4	20	40	60	30	50	11.00
	空载陡坡	49.83	20	50	85	30	70	18.59
四轴货车	满载缓坡	55.42	20	60	70	50	70	13.0
	空载缓坡	68.89	60	70	80	60	80	7.40
	满载陡坡	45.33	15	50	70	20	60	18.75
	空载陡坡	61.09	40	60	80	50	77	12.25
五、六轴货车	满载缓坡	48.43	15	50	80	35	60	15.01	<0.001
	空载缓坡	57.96	20	60	80	40	80	15.94
	满载陡坡	37.39	15	37.5	70	28	50	11.97
	空载陡坡	47.13	20	50	70	30	70	15.17