To the Board of Directors and stakeholders of Transurban:

Transurban Limited (Transurban) commissioned Net Balance Management Group Pty Ltd (Net Balance) to provide an independent assurance of the non-financial content of this Transurban Sustainability Report 2007 (the ‘report’). The report presents Transurban's sustainability performance over the period 1 July 2006 to 30 June 2007. Transurban was responsible for the preparation of the report and this statement represents the assurance provider’s independent opinion. Net Balance’s responsibility in performing its assurance activities is to the management of Transurban alone and in accordance with the terms of reference agreed with them. Any reliance third parties may place on this statement is entirely at their own risk.

Assurance objectives

The objective of the assurance process is to provide stakeholders of Transurban with an independent opinion on the materiality, completeness and accuracy of the information presented within the report, and whether Transurban has responded to stakeholders’ concerns and adequately communicated those responses within the report. This is confirmed through a review of selected claims made, underlying systems, processes and competencies that support the production of the report, as well as the extent to which policies and strategies relating to sustainability are embedded. Ensuring continuous improvement in data management systems and associated reporting processes is also a complementary objective.

Assurance process

Our approach to assurance provision is aligned to the AA1000 Assurance Standard. The assurance engagement was undertaken in October 2007. The process involved:

• a review of Transurban’s key sustainability strategies, policies, objectives, management systems, background documentation and procedures for measurement, data collection and reporting
• a review of the report for any significant anomalies, particularly in relation to significant claims as well as trends in data
• an overview of the extent to which Transurban’s key economic, environmental and social policies are embedded in the organisation
• a series of interviews with key personnel responsible for collating and writing various parts of the report in order to substantiate the veracity of selected claims
• an examination of the aggregation and/or derivation of, and underlying evidence for, over 80 selected data points and statements made in the report. The verified items were broadly selected to not only satisfy the principles of materiality, completeness and responsiveness, but also as supporting evidence for conclusions reached, and
• a review of selected external media sources relating to Transurban's sustainability performance so as to further substantiate reported claims and, more importantly, to ensure that no significant omissions were made in the report.

The assurance process was carried out under Net Balance’s quality control procedures.

Assurance limitations

Our scope of work did not involve verification of the accuracy and robustness of financial data, other than that relating to environmental, social or broader economic performance. The NSW office of Hills M2 in North Ryde was also visited, but there was no assurance work undertaken for the Westlink M7 in Sydney.

Our independence

Net Balance was not responsible for the preparation of any part of this report. Net Balance has not undertaken any commissions for Transurban in the reporting period concerning reporting or data collection. Our independence was further ensured by selecting an assurance team that had no other involvement with Transurban during the reporting period that could impair the team’s independence or objectivity.

Our capacity

The assurance team comprised of individuals with expertise in environmental and social performance measurement and reporting. The assurance team has collectively undertaken over 70 assurance engagements in Australia over the past ten years and is also led by a Lead Sustainability Assurance Practitioner (Lead CSAP) accredited by the Independent Register of Certified Auditors (IRCA) UK. The team is also a global leader in the use of the AA1000 Assurance Standard in assurance provision.

Our opinion

Based on the scope of the assurance process, the following represents the assurance provider’s opinion:

• The findings of the assurance engagement provide confidence in the reporting processes established and the information provided within the report. The level of data accuracy was found to be high, but some additional improvements to data management, including the reduction of manual aggregation and transcription processes are recommended to reduce potential for minor anomalies. Data trails selected were easily identifiable and traceable, and the personnel responsible were able to reliably demonstrate the origin(s) and interpretation of data.
• The statements made in the report appropriately reflect environmental, social and economic performance achieved during the period.
• All suggested changes were satisfactorily addressed by Transurban prior to finalising the report. Overall, the assurance provider is satisfied that the report is an appropriate representation of Transurban’s sustainability performance during the reporting period.

Conclusions

• Materiality: Issues material to stakeholders have been considered and communicated within the report. Materiality was determined by assessing compliance performance, issues material to stakeholders, policy-related performance and peer-based norms. It was found that material issues relating to Transurban’s environmental, social and broader economic aspects of its sustainability performance are appropriately addressed.
• Completeness: The report was found to be complete in addressing key environmental, social and economic performance as well as all operations of Transurban using the Global Reporting Initiative’s (GRI) G3 as a guide. Completeness was also achieved by Transurban taking into account the entire chain of entities and covering all information that are material to the operation of the company.
• Responsiveness: Net Balance tested the responsiveness of the organisation through a review of management systems, documents and policies prepared by the organisation relating to the way it responds to stakeholders’ concerns and interests; by assessing the resources allocated to implement the aforementioned policies and commitments; by assessing the timeliness and accessibility of reported information; and by undertaking a review of key policies, targets and indicators and assessing the extent to which these are implemented by Transurban.

The way forward

Transurban sees sustainable development and management as a core value proposition. Transurban has focused its sustainability effort over the past few years on integrating sustainability principles within its business at all levels. This has resulted in management commitment, an increased level of awareness of Transurban’s own environmental and social footprint, and an aspiration to lead the sector and influence partners, customers and peers to become more sustainable. Transurban has produced a comprehensive report that provides detailed data and commentary on organisational performance indicators, targets and other measures for the organisation, which represents best practice and a commendable framework for reporting.

In terms of direct impact, the organisation’s characterisation of its environmental footprint is adequate. Improved environmental performance is possible with the introduction of challenging targets particularly in the greenhouse gas emissions. On the other hand, understanding around its social footprint is still developing. Net Balance also recommends that some systems and quality controls for the collection and reporting of social data such as donations and toll waivers are developed, which would further assist in reporting efficiency.

Results of stakeholder engagement in 2007 have presented Transurban with a challenge to shift some focus from environmental issues towards transport integration issues and establishing links between transport integration and sustainability. This would show leadership in the transport sector and bring sustainability issues to the forefront.

Another key challenge for Transurban is the measuring and managing of indirect impacts made by customers and the supply chain as the transport industry and Transurban grow. Since work relating to indirect impacts is still in its infancy, Transurban is well positioned to show leadership in the transport sector by starting to investigate and direct these effects beyond its sphere of direct influence, for example, the development of a sustainability procurement policy.

Net Balance has provided additional suggestions for reporting improvement in some areas. These have been outlined in a more detailed report presented to the Transurban Board and executive team.