Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed

Experimental investigation was conducted on a 24 km long segment of the two-lane state road to collect the driver behavior data. The research involved 20 drivers driving their own cars equipped with the GPS device. Considering the impact of path radius and speed on the side friction demand, the desi...

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Main Authors: Biljana Maljković, Dražen Cvitanić
Format: Article
Language:English
Published: Riga Technical University Press 2016-06-01
Series:The Baltic Journal of Road and Bridge Engineering
Subjects:
Online Access:https://bjrbe-journals.rtu.lv/article/view/3330
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author Biljana Maljković
Dražen Cvitanić
author_facet Biljana Maljković
Dražen Cvitanić
author_sort Biljana Maljković
collection DOAJ
description Experimental investigation was conducted on a 24 km long segment of the two-lane state road to collect the driver behavior data. The research involved 20 drivers driving their own cars equipped with the GPS device. Considering the impact of path radius and speed on the side friction demand, the design consistency on horizontal curves was evaluated by determining the margins of safety. The analysis showed that the vehicle path radii were mainly smaller than curve radius, on average for 12%. Regression analysis indicated that the percentage difference between the curve radius and vehicle path radius is not affected by the speed, speed differential and geometric characteristics of the curve and surrounding elements. Two different margins of safety were analyzed. One is the difference between maximum permissible side friction (based on design speed) and side friction demand, while another is the difference between side friction supply (based on operating speed) and side friction demand. Generally, demands exceeded supply side friction factors on curves with radii smaller than 150 m, whereas “poor” conditions (in terms of Lamm’s consistency levels) were noted for curves under approximately 220 m. Both values are very close to the critical radius below which higher accident rates were observed according to several accident studies. Based on the results of the research, it is proposed to use a 12% smaller curve radius for the evaluation of margin of safety and that curves with radii smaller than 200 m should be avoided on two-lane state roads outside the built-up area.
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issn 1822-427X
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publishDate 2016-06-01
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series The Baltic Journal of Road and Bridge Engineering
spelling doaj-art-8d519e3c85c047f9958bf4f6b524889c2025-01-02T11:43:10ZengRiga Technical University PressThe Baltic Journal of Road and Bridge Engineering1822-427X1822-42882016-06-0111210.3846/bjrbe.2016.151824Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and SpeedBiljana Maljković0Dražen Cvitanić1Dept of Transportation, University of Split, Matice hrvatske 15, 21000 Split, CroatiaDept of Transportation, University of Split, Matice hrvatske 15, 21000 Split, CroatiaExperimental investigation was conducted on a 24 km long segment of the two-lane state road to collect the driver behavior data. The research involved 20 drivers driving their own cars equipped with the GPS device. Considering the impact of path radius and speed on the side friction demand, the design consistency on horizontal curves was evaluated by determining the margins of safety. The analysis showed that the vehicle path radii were mainly smaller than curve radius, on average for 12%. Regression analysis indicated that the percentage difference between the curve radius and vehicle path radius is not affected by the speed, speed differential and geometric characteristics of the curve and surrounding elements. Two different margins of safety were analyzed. One is the difference between maximum permissible side friction (based on design speed) and side friction demand, while another is the difference between side friction supply (based on operating speed) and side friction demand. Generally, demands exceeded supply side friction factors on curves with radii smaller than 150 m, whereas “poor” conditions (in terms of Lamm’s consistency levels) were noted for curves under approximately 220 m. Both values are very close to the critical radius below which higher accident rates were observed according to several accident studies. Based on the results of the research, it is proposed to use a 12% smaller curve radius for the evaluation of margin of safety and that curves with radii smaller than 200 m should be avoided on two-lane state roads outside the built-up area.https://bjrbe-journals.rtu.lv/article/view/3330critical vehicle path radiusdemand side friction factordesign consistencyglobal positioning system (gps)horizontal curveoperating speed.
spellingShingle Biljana Maljković
Dražen Cvitanić
Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed
The Baltic Journal of Road and Bridge Engineering
critical vehicle path radius
demand side friction factor
design consistency
global positioning system (gps)
horizontal curve
operating speed.
title Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed
title_full Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed
title_fullStr Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed
title_full_unstemmed Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed
title_short Evaluation of Design Consistency on Horizontal Curves for Two-Lane State Roads in Terms of Vehicle Path Radius and Speed
title_sort evaluation of design consistency on horizontal curves for two lane state roads in terms of vehicle path radius and speed
topic critical vehicle path radius
demand side friction factor
design consistency
global positioning system (gps)
horizontal curve
operating speed.
url https://bjrbe-journals.rtu.lv/article/view/3330
work_keys_str_mv AT biljanamaljkovic evaluationofdesignconsistencyonhorizontalcurvesfortwolanestateroadsintermsofvehiclepathradiusandspeed
AT drazencvitanic evaluationofdesignconsistencyonhorizontalcurvesfortwolanestateroadsintermsofvehiclepathradiusandspeed