The WhichBridge algorithm is a qualitative risk management tool that is used to benchmark network performance and assist in the prioritisation of bridge and culvert rehabilitation works within Transport and Main Roads (TMR). WhichBridge was first implemented by TMR in 2003 and was integrated into the BIS in 2005. There have been a number of changes and updates to the algorithm to better reflect the existing network. The user manual has not been updated to reflect these changes.   

The overall aim of this project was to review the use of WhichBridge across TMR operational districts and historical changes to the algorithm, in order to identify issues or limitations of the algorithms and inconsistencies in the outputs (risk scores). Based on the findings of the review, various recommendations have been made on changes to the algorithms and further calibrations required to better reflect the existing condition of the network and current TMR practice in data collection, management and maintenance/rehabilitation prioritisation and programming. The WhichBridge User Manual has also been updated accordingly. 

• Provide an updated user manual for WhichBridge, which includes a targeted guide for how to perform common tasks within WhichBridge and Whatif modules.
• Improve TMR knowledge on how WhichBridge is used in regions and stakeholders’ expectations for future improvement.
• Improve TMR knowledge of factors that affect risk scores and risk score anomalies.
• Capture corporate knowledge on the historical changes to WhichBridge algorithms to better reflect the existing network conditions and operational needs.