Fatal crashes at T-junctions within New South Wales

Blades, Tyson (2017) Fatal crashes at T-junctions within New South Wales. [USQ Project]


Annual statistics from the NSW Centre for Road Safety show that the number of fatal crashes at T-junctions has been consistently higher than at any other basic intersection type during the past decade. The purpose of this research was to investigate the attributes of fatal crashes at T-junctions in NSW and identify factors demonstrated to contribute to these crashes using crash data. The project was aimed at understanding why fatal crashes occur at T-junctions, regardless of the perceived advantages that they have over other types of basic intersection.

The crash data for this project was provided by the NSW Centre for Road Safety. A network screening process was used to identify all T-junctions in NSW where there was a fatal crash during the study period (2011-2015). Validation of the raw data resulted in 200 crash records being adopted for the purposes of this research. Traffic volumes were obtained from the RMS Traffic Volume Analysis database in the form of Annual Average Daily Traffic (AADT) counts, enabling 110 of the 200 validated crash records to be analysed in consideration of traffic exposure. A strong correlation between traffic volumes and fatal crash occurrences was identified, with a trend showing a decrease in the number of fatal crashes across the network with increasing traffic volumes at T-junctions (supported by an R2 value of 0.9239).

Two-thirds of all fatal crashes occurred in urban network environments, and most fatal crashes occurred at T-junctions with posted speed limits of 50 km/h and 60 km/h. Travel speeds above 50 km/h with impact angles of 90° do not meet tolerable human thresholds of kinetic energy in accordance with Safe Intersection Design Principles (SIDPs). Current design standards recommend T-junctions be aligned to intersect at right-angles which promotes side impacts. This leads to crashes occurring at the most severe of angles and does not allow T-junctions to operate without the potential for severe or fatal injuries. Right-angle
first impact types were found to be the most common crash type for fatalities at T-junctions.

Factors contributing to fatal crashes at T-junctions in NSW included the traffic unit group involved, the age group and gender of primary at fault vehicle controllers, and the age group of those involved in the crashes. The combined VRU groups (motorcycles, pedestrians and pedal cycles) accounted for over half (52.9%) of all fatalities. A high proportion of older road users, aged 70 years and over, were deemed to be primary at fault vehicle controllers,
particularly at unsignalised intersections. Those aged 70 and over also had the highest number of fatalities, accounting for one-third of all those at T-junctions.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Honours) (Civil) project.
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
Date Deposited: 22 Mar 2021 04:42
Last Modified: 11 Aug 2021 02:38
Uncontrolled Keywords: fatal crashes; traffic accidents; T-junctions; road safety; New south Wales
Fields of Research (2008): 09 Engineering > 0905 Civil Engineering > 090507 Transport Engineering
Fields of Research (2020): 40 ENGINEERING > 4005 Civil engineering > 400512 Transport engineering
URI: https://sear.unisq.edu.au/id/eprint/40825

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