Analysis of the Suitability of Roundabouts for Heavy Vehicles driving at High Speeds in Queensland

Young, Lauren (2021) Analysis of the Suitability of Roundabouts for Heavy Vehicles driving at High Speeds in Queensland. [USQ Project]

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Roundabouts are defined as unsignalized intersections which circulate traffic around a central island in a clockwise manner and are primarily made up of curves which are designed to slow entering and circulating as they navigate the roundabout. Roundabouts have long been considered the safest form of intersection control, but this is perception is generally based on smaller, passenger vehicles, not heavy vehicles. Due to their different characteristics, such as a high centre of gravity and varying load distribution, heavy vehicles behave very differently on roundabouts, when compared to passenger vehicles. This research project aims to investigate the current roundabout geometric standards in place in Queensland for heavy vehicles and evaluate their effectiveness in safely allowing heavy vehicles to navigate high-speed roundabouts. Additionally, this project aims to offer improvements and amendments to the current standards to cater for heavy vehicles.

Roundabout intersections are often being placed on arterial roads nowadays due to their efficiency and ease for right-hand turning traffic, as they withdraw the need for a vehicle to cross high-speed roadways. Additionally, the tendency to reduce crashes, by means of encouraging traffic to decelerate through geometric features and reducing the relative speed differences between entering and circulating traffic, reduces the risks involved with intersections on high-speed roadways. High-speed roundabouts offer more concerning factors than low-speed roundabouts, due to the likelihood of a vehicle entering the roundabout at a greater speed, as well as increased heavy vehicle traffic. It is vital that highspeed roundabouts are designed to safety cater for all possible design vehicles, noting the vast difference between smaller, passenger vehicles and heavy vehicles.

Analysis of the current Queensland and Australian standards is conducted, as well as a case study on a high-speed roundabout in Queensland’s Mackay region. A Roundabout Numerical Design Tool (ARNDT) was utilised to compare current standards in place, to the revised standards and new recommended values as found in this study. The likelihood of crashes as well as the side frictional values generated from this model was compared and critically analysed to allow for recommendations and amendments to the current standards to be made.

A critical review of relevant or similar standards, from other states and countries was carried out, and utilised to ensure the best analysis practice was employed and to ensure the amendments recommended are in-line with those already adopted on a national scale. A list of amendments was developed and formatted in a similar way to the current amendment documents released by the Queensland Department of Transport and Main Roads.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Somasundaraswaran, Soma
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 03 Jan 2023 22:11
Last Modified: 26 Jun 2023 03:29
Uncontrolled Keywords: roundabouts, heavy vehicle, truck, Queensland, safety, ARNDT, roundabout numerical design tool, crash, friction, speed, safety

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