Study Details

Study Title: Development of Crash Modification Factors for Intersections in Toowoomba city

Authors: Al-Marafi et al.

Publication Date: MAR, 2020

Abstract: employed to recommend multiple treatments for application to improve safety level at hazardous intersections in regional areas. Data from 106 intersections in the regional city of Toowoomba, Queensland, Australia were used in modelling and subsequent analysis. Specifically, crash prediction models were developed to estimate crash modification factors that could be used to propose remedial measures. A total of sixteen geometric and operational conditions were used as explanatory variables including the number of legs at an intersection, the availability of entering and exiting via through lanes, the presence of left-turning lanes, right turning lanes, slip lanes, median islands, traffic control, and speed limits on the feed roads. The Empirical Bayes approach was employed to identify five hazardous intersections in Toowoomba for further investigation. The four most suitable techniques for estimating combined crash modification factors were reviewed and then used to propose effective road safety measures for the five selected hazardous intersections. Finally, this research suggests four future areas worthy of further investigation.

Study Citation: Al-Marafi, M.N., K. Somasundaraswaran, and F. Bullen. "Development of crash modification factors for intersections in Toowoomba city". International Journal of Urban Sciences, Vol. 25(1), (2010) pp. 104-123.

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Access management

Countermeasure: Install raised median

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.72 28 3 Stars All K,A,B,C All All
0.58 42 3 Stars All K,A,B,C All All

Category:Intersection geometry

Countermeasure: Change number of through lanes on minor road (from 2 to 1)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.88 12 3 Stars All K,A,B,C All All

Countermeasure: Install left-turn lane

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.96 4 2 Stars All K,A,B,C All All
0.92 8 2 Stars All K,A,B,C All All

Countermeasure: Install Slip Lane

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.97 3 2 Stars All K,A,B,C All All
0.94 6 2 Stars All K,A,B,C All All

Category:Intersection traffic control

Countermeasure: Install a traffic signal

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.87 13 2 Stars All K,A,B,C All All

Category:Speed management

Countermeasure: Lower posted speed from 60 km/h to 50 km/h

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.68 32 3 Stars All K,A,B,C All All