Operator rating system

How we calculate your rating - The algorithm

Principles of the algorithm

The Operator Safety Rating (OSR) takes into account a broad range of events 

Certificate of Fitness (CoF) inspections, roadside inspections, and offences will be included in the initial safety ratings. All events commenced during the rating period are taken into account and eligibility will be determined by the start and end dates of the rating period. Only events attributed to a vehicle operator’s TSL number will be included in that operator’s rating.

Events types are weighted based on their safety risk

Risk analysis will determine event types posing the biggest risk to road safety, and events will be weighted accordingly.  For example, if it is found that offences, pose the highest risk to road safety, then offence events will contribute more to the rating than other event types.

COF and roadside faults are weighted according to their severity

Some faults pose a bigger safety risk than others. For example, brakes, lighting and tyres play a greater part in vehicle safety than issues with the cab or speedometer. Faults will be weighted according to the risk they pose to safety so that more serious faults are reflected by a poorer rating.

Events are aged

Events are ‘aged’ so that the longer ago an event happened, the less effect it has on the safety rating.  A half-life scaling factor is applied to events, and this reduces their influence over time.

The algorithm will take into account the number of COF and roadside inspections in the rating period

The inspection score is a weighted average, where the total COF or roadside inspection score is divided by the number of COF or roadside inspections that occurred. Both the inspection score and the number of inspections are weighted according to the age of the event, so that their influence is reduced over time.

The algorithm will take into account exposure to offences and crashes

The likelihood of a vehicle being involved in a crash or its driver being issued an offence notice is relative to the amount of time that vehicle or driver actually spends on the road. The algorithm will average scores over the road usage (number of vehicle kilometres travelled) in the rating period.

Changes to the weightings, event types included or other aspects of the algorithm will be consulted on and communicated to operators

Operators will have the opportunity to provide feedback, and to alter processes to comply with new standards and reduce the impact of events on their rating.

The algorithm is independently reviewed

The rating algorithm has been independently reviewed and quality assured by an academic expert in statistics, who has confirmed that the algorithm is sound and fit for the purpose of producing operator safety ratings. A separate independent study into the safety-related risks impacting on transport operators, drivers and vehicles has also been undertaken. This study will inform the weightings assigned to each event type.

Diagram - how it works

*The weighted average is calculated by adding together the aged scores and dividing them by the aged denominator (number of inspections or road usage)

Page updated: 2 September 2009