Our Team

Some of our team members

Tim Lewis

Principal Lead – Development Assessment & Advisory

Tim has a Bachelor of Civil Engineering and demonstrated ability in transport planning.

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An accredited Level 2 Road Safety Auditor and member of the Engineers Australia National Engineering Register (NER), Tim has acted as an Expert Witness to the Land & Environmental Court and been involved in many significant studies for both developers and government agencies, including Councils and Transport for NSW.

Past projects have ranged from detailed design advice for developments with highly constrained access to the preparation of Transport Management and Accessibility Plans for large precinct rezonings involving consideration of Movement & Place outcomes to drive the right outcomes for clients and the community.

Experience from early Due Diligence to the preparation of post-opening Operational Traffic Management Plans – together with the numerous transport planning models –allows Tim to provide strategic and specialist advice on transport issues at an early stage whilst understanding the practical considerations to implementation.


Ason Groups:

Other Key Personnel:

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Becky is a Senior Transport Planner with over 8 years’ experience in local government and private consultancy fields.

Rebecca Butler-Madden

Principal Transport Planner

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Piran Trethewey, a founding director of Ason Group, is an experienced traffic engineer with expertise in the areas of traffic engineering analysis and assessment.

Piran Trethewey


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Andrew Johnson, a founding director of Ason Group, is a Civil Engineer with over 20 years of experience in the Transport Planning and Engineering industry.

Andrew Johnson