title: Experimental research on the effectiveness and adaptability of speed reduction markings in downhill sections on urban roads: a driving simulation study.
abstract: The objective of this paper is to test the effectiveness and adaptability of speed reduction markings (SRMs) in downhill sections on urban roads with distinct roadway grades. Empirical data including vehicle speed and acceleration were collected in a driving simulator. Subjective questionnaires were conducted, and two indexes - the relative speed difference and standard deviation of acceleration - were developed to evaluate the effectiveness and adaptability of SRMs. Meanwhile, the effectiveness of driving simulator related to different road alignments and types of SRMs has been validated through a field test. Results of subjective questionnaires showed that the majority of subjects had no feelings of nervousness, but they were affected by SRMs while driving through downhill sections in all four scenarios (i.e., downhill sections with vertical grades of 3, 2, 1.5 and 1%). In terms of vehicle speed and acceleration, the results of the analysis of variance (ANOVA) and the contrast analysis (S-N-K method) indicated that SRMs were significantly effective when roadway grades of downgrade sections were 1.5, 2 and 3%, while transverse speed reduction markings (TSRMs) had significantly worse adaptability (P<0.05). Therefore, this research recommends that TSRMs could be placed in downhill sections with roadway grades of 1.5 or 2%; longitudinal speed reduction markings (LSRMs) could be placed in downhill sections with a roadway grade of 3%. Whether SRMs are placed in downhill sections with a roadway grade of 1% would depend on other factors such as financial issues and crash records, which are not considered in this paper.
authors.affiliation: College of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, PR China. Electronic address: dinghan86@hotmail.com.
authors.forename: Han
authors.initials: H
authors.lastname: Ding
authors.affiliation: College of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, PR China. Electronic address: zhaoxiaohua@bjut.edu.cn.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Zhao
authors.affiliation: College of Metropolitan Transportation, Beijing University of Technology, Beijing 100124, PR China. Electronic address: jrong@bjut.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Rong
authors.affiliation: Traffic Operations Division Texas Department of Transportation Austin, TX 78701-2483, USA. Electronic address: jianming.ma@txdot.gov.
authors.forename: Jianming
authors.initials: J
authors.lastname: Ma
mesh_terms: D000056:Accident Prevention / Q000379:methods; D000063:Accidents, Traffic / Q000517:prevention & control*; D000704:Analysis of Variance; D001334:Automobile Driving / Q000706:statistics & numerical data*; D003198:Computer Simulation; D003654:Deceleration; D004779:Environment Design; D006801:Humans; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D014505:Urban Population
keywords: Adaptability; Downhill sections; Driving simulator; Effectiveness; Roadway grade; Speed reduction markings