Development of Crash Modification Factors Using Selected Remedial Measures at Signalised Cross Intersections in Toowoomba

Somasundaraswaran, Aruthra (2017) Development of Crash Modification Factors Using Selected Remedial Measures at Signalised Cross Intersections in Toowoomba. [USQ Project]


Annual cost of road crashes in Australia was estimated in 2008 to be $27 billion without considering other consequences such as damage to the society. Analysis of road crash records showed that around fifty percentage of all crashes happened at intersections in Queensland, and the crashes at signalised cross intersections in Toowoomba was about thirty percentage. This study aimed to propose remedial measures for signalised cross intersections in Toowoomba by identifying poorly performing intersections, developing Safety Performance Functions (SPFs), estimating Crash Modification Factors (CMFs) and site audits.

The critical crash rate threshold method was utilised to rank the worst performing intersections in Toowoomba, since this method was ideal for ranking the intersections as it considered the number of crashes at an intersection in regards to the traffic volume that the intersection experienced. The top ten poorly performing intersections were selected for further investigation to determine the geometric factors that could be changed to reduce the number of crashes at that intersection.

The safety performance functions were developed and tested using statistical approach, where correlation matrix was used to identify the dependant variables from sixteen geometric and operational parameters. The model developed for total crashes showed that traffic volume through an intersection and presence of median islands in the major lane was significant factors that influenced the number of crashes. The models were also specifically developed for both angle and rear end crashes as these were the most common type of crashes at signalised cross intersections in Toowoomba. In this analysis it was determined that median islands in the major lane could helped in reducing angle crashes while percentage of heavy vehicles, designated right turn lane for minor lane and designated left turn lane for major lane helped reduce rear end crashes.

The aforementioned remedial actions were trialled using the developed models on the poorly performing intersections, and CMFs were estimated for various forms of remedial actions. The site visits were then conducted to determine the suitability of the proposed remedial actions for the selected intersection in order recommend acceptable geometric changes to improve the safety at selected intersections. The opening for new research areas have been identified along with the limitation of this study.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Honours) (Civil)
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Drysdale, Trevor
Date Deposited: 07 Sep 2022 03:04
Last Modified: 07 Sep 2022 03:04
Uncontrolled Keywords: road crashes; signalised cross intersections

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