Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed

Geometric road design consistency modelling is used to detect any inconsistencies in road alignment, particularly horizontal and vertical alignment. Unusual features of road geometries or inconsistencies can produce unsafe driving experience due to carelessness in the handling of vehicles. To help m...

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Main Author:	Mohamed, Nadiah
Format:	Thesis
Language:	English
Published:	2013
Online Access:	https://ir.uitm.edu.my/id/eprint/18411/2/TM_NADIAH%20MOHAMED%20EC%2013_5.pdf
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id	my-uitm-ir.18411
record_format	uketd_dc
spelling	my-uitm-ir.184112023-03-08T02:12:12Z Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed 2013-07 Mohamed, Nadiah Geometric road design consistency modelling is used to detect any inconsistencies in road alignment, particularly horizontal and vertical alignment. Unusual features of road geometries or inconsistencies can produce unsafe driving experience due to carelessness in the handling of vehicles. To help minimize the risk of accidents at the curve, the 85th percentile speed prediction model is needed for the Malaysia scenario to ensure the road consistency. The current technique of identifying speed design based on REAM (2002) guidelines is prone to produce inconsistencies in road design. This is because the geometric elements determined from the identified speed design are based on minimum values and it is recommended to adopt higher values for the purpose of road construction (REAM, 2002). However, no maximum value has been set up thus leads towards under-design or over-design of road geometry specifications. With this in mind, this research aims to develop models for the purpose of predicting consistencies of urban road specifically for horizontal alignment curves with novel methodology adopted in this study. Several techniques were adopted such as spot speed study, VBOX-GPS and Automatic traffic counter detector and had been successfully performed. Parameters collected are the curve length, radius of curve, width of lane, vehicle speed at the beginning of the curve, at the middle of the curve and at the end of the curve, superelevation and road gradient. By adopting multiple regression analysis, one model for the beginning of the curve, V85cs, one model for the middle of the curve,V85cm and one model for the end of the curve, V85ce with R-Sq value of more than 50% were successfully developed. These regression models generally estimates 85th percentile operating speed at specified points along the curve. V85cs> V85cm and V85ce were further validated to confirm of its usefulness in predicting the value of operating speed for horizontal alignment. Validation of models were performed by comparing the mean difference of the develop regression models with the empirical data which is isolated from being used in the model development process. Comparisons of V85cm and three models from other researchers were also conducted and it revealed that V85cm is more superior compared to the other models developed from other researchers and established guidelines from overseas. It was also discovered that radius of curve, CR is highly sensitive in predicting the 85th percentile operating speed at the middle of curve compared to superelevation and V85(CS). To conclude, fundamental differences indriving behaviour, traffic composition and road design standard guideline used may contribute to high difference of R-Sq values between the established models and V85cm- Furthermore, other models are not reflective of Malaysian road conditions and this was discovered in the comparisons conducted in this study. All these factors might contribute to the overestimation or underestimation of the models. Therefore, the developed models in this study are proposed to be a starting basis of the prediction of the 85th percentile operating speed model to be included in the Malaysian urban geometric road design guidelines. 2013-07 Thesis https://ir.uitm.edu.my/id/eprint/18411/ https://ir.uitm.edu.my/id/eprint/18411/2/TM_NADIAH%20MOHAMED%20EC%2013_5.pdf text en public mphil masters Universiti Teknologi MARA Faculty of Civil Engineering
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
description	Geometric road design consistency modelling is used to detect any inconsistencies in road alignment, particularly horizontal and vertical alignment. Unusual features of road geometries or inconsistencies can produce unsafe driving experience due to carelessness in the handling of vehicles. To help minimize the risk of accidents at the curve, the 85th percentile speed prediction model is needed for the Malaysia scenario to ensure the road consistency. The current technique of identifying speed design based on REAM (2002) guidelines is prone to produce inconsistencies in road design. This is because the geometric elements determined from the identified speed design are based on minimum values and it is recommended to adopt higher values for the purpose of road construction (REAM, 2002). However, no maximum value has been set up thus leads towards under-design or over-design of road geometry specifications. With this in mind, this research aims to develop models for the purpose of predicting consistencies of urban road specifically for horizontal alignment curves with novel methodology adopted in this study. Several techniques were adopted such as spot speed study, VBOX-GPS and Automatic traffic counter detector and had been successfully performed. Parameters collected are the curve length, radius of curve, width of lane, vehicle speed at the beginning of the curve, at the middle of the curve and at the end of the curve, superelevation and road gradient. By adopting multiple regression analysis, one model for the beginning of the curve, V85cs, one model for the middle of the curve,V85cm and one model for the end of the curve, V85ce with R-Sq value of more than 50% were successfully developed. These regression models generally estimates 85th percentile operating speed at specified points along the curve. V85cs> V85cm and V85ce were further validated to confirm of its usefulness in predicting the value of operating speed for horizontal alignment. Validation of models were performed by comparing the mean difference of the develop regression models with the empirical data which is isolated from being used in the model development process. Comparisons of V85cm and three models from other researchers were also conducted and it revealed that V85cm is more superior compared to the other models developed from other researchers and established guidelines from overseas. It was also discovered that radius of curve, CR is highly sensitive in predicting the 85th percentile operating speed at the middle of curve compared to superelevation and V85(CS). To conclude, fundamental differences indriving behaviour, traffic composition and road design standard guideline used may contribute to high difference of R-Sq values between the established models and V85cm- Furthermore, other models are not reflective of Malaysian road conditions and this was discovered in the comparisons conducted in this study. All these factors might contribute to the overestimation or underestimation of the models. Therefore, the developed models in this study are proposed to be a starting basis of the prediction of the 85th percentile operating speed model to be included in the Malaysian urban geometric road design guidelines.
format	Thesis
qualification_name	Master of Philosophy (M.Phil.)
qualification_level	Master's degree
author	Mohamed, Nadiah
spellingShingle	Mohamed, Nadiah Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed
author_facet	Mohamed, Nadiah
author_sort	Mohamed, Nadiah
title	Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed
title_short	Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed
title_full	Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed
title_fullStr	Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed
title_full_unstemmed	Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed
title_sort	development of operating speed prediction models for horizontal curve based on urban arterial roadway / nadiah mohamed
granting_institution	Universiti Teknologi MARA
granting_department	Faculty of Civil Engineering
publishDate	2013
url	https://ir.uitm.edu.my/id/eprint/18411/2/TM_NADIAH%20MOHAMED%20EC%2013_5.pdf
_version_	1783733674704896000

Development of operating speed prediction models for horizontal curve based on urban arterial roadway / Nadiah Mohamed

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