Traffic & Transport
Traffic Impact Assessments (TIA)
A traffic impact assessment is an engineering report that shows how a proposed development will affect the surrounding road network — and what, if anything, is needed to make it work safely.
What it is
A traffic impact assessment (TIA) is a report that estimates the traffic a development will generate, tests how the surrounding road network and intersections will cope, and recommends any changes needed so the development can operate safely and without unreasonable impact. It is one of the most common pieces of supporting information a council or road authority asks for when assessing a planning permit or development application. A good TIA does two jobs at once: it satisfies the authority, and it gives you an early, honest read on whether your site works.
When you need it
You typically need a TIA when a development changes how much traffic uses the road network — for example a new or expanded residential, commercial, industrial or mixed-use project, a change of use that increases parking demand or vehicle trips, or a proposal on or near a road managed by the state road authority. In Victoria, a TIA is commonly required where a proposal increases the statutory car parking requirement under Clause 52.06 or generates enough new peak-hour traffic that council or the Department of Transport and Planning (DTP, formerly VicRoads) wants the impact assessed. In Queensland, a TIA is commonly required where a development adds materially to movements on a state-controlled road. If you're not sure whether your project needs one, that's exactly the kind of question a short scoping call answers.
Who requires it
The report is usually requested by the responsible authority assessing your application — most often the local council, and, where a state road is involved, the state road authority as a referral authority (DTP in Victoria; the Department of Transport and Main Roads (TMR) in Queensland). Developers, town planners, architects and building designers commission the TIA so their planning application is complete and ready for assessment.
What Arcvia assesses
Our engineering team looks at the whole picture, not just a trip count:
- Existing traffic conditions and how the surrounding network operates today
- Trips the development is expected to generate, and how they distribute onto the network
- Intersection and access performance (including capacity analysis where warranted)
- Car parking provision and demand, and loading/servicing arrangements
- Sight lines, access safety and swept paths for the largest vehicles using the site
- Active transport, public transport and any relevant safety considerations
- Practical recommendations to address whatever the analysis turns up
What you receive
A clear, standards-based TIA report that includes a plain-language summary of findings, the technical analysis and figures behind it, a statement of impact, and specific recommendations. It is written so a planner or councillor can follow the argument, with the detail an engineer or referral officer needs sitting behind it — structured to anticipate the questions the authority will ask.
Standards, guidelines & authorities
Our assessments are prepared with reference to the current standards and guidelines that apply to your jurisdiction, which commonly include the relevant Austroads guides, the applicable Australian Standards, and the local planning scheme. In Victoria, that includes the Victoria Planning Provisions (including Clause 52.06 for car parking) and DTP requirements where a state road is involved. In Queensland, that includes TMR's Guide to Traffic Impact Assessment for state-controlled roads and the relevant council requirements. We confirm the specific, current references that apply to your site at scoping.
Information we need for your fee proposal
To give you an accurate fee, it helps to have: the site address; the proposed development (plans or a description, and the number of dwellings/GFA/use); the planning stage you're at; any council or referral-authority correspondence or pre-application advice; and your target timeframe. If you don't have all of it yet, send what you have — we'll tell you what else is needed.
Our process
- Enquiry & scoping — we confirm what the authority is likely to require for your site.
- Fee proposal — scope, deliverables and fee set out in writing before work starts.
- Data — we obtain or commission the traffic counts and site information the assessment needs.
- Analysis — trip generation, distribution, and intersection/access assessment.
- Draft report — issued for your review, with findings explained plainly.
- Finalisation — we finalise the report for lodgement.
- Support — we remain available to respond to council or referral-authority questions.
We are clear about timeframes at scoping; we do not promise approvals or fixed turnaround before we understand your project.
Frequently asked questions
Often, yes — but not always. You generally need a TIA when your development increases traffic or parking demand, changes an access, or sits on or near a road the state road authority manages. The clearest way to know is to check your council's requirements (or any pre-application advice) for your specific site, or ask us in a short scoping call. We would rather tell you honestly that you don't need one than sell you a report you can't use.
It depends on the size and complexity of the development, the amount of data and modelling required, and the authorities involved — so we quote each project individually rather than publishing a flat price. We set the fee out in writing before any work begins, and we're happy to talk through what drives the cost for your project.
That depends on scope, data availability (traffic counts sometimes need to be surveyed, which takes time) and how quickly plans are finalised. We give you a realistic timeframe at scoping and keep you updated — we don't quote a headline turnaround before we understand the job.
They overlap. “Traffic report” is a general term councils and applicants use; a “traffic impact assessment” is the more formal engineering assessment of a development's traffic effects. For a smaller proposal a council may accept a shorter traffic report or statement; for a larger one they'll expect a full TIA. We scope the right level of report for what your application actually needs.
No — and be cautious of anyone who says it will. A TIA is technical evidence that supports your application; the decision rests with the responsible authority. What a well-prepared TIA does is anticipate the authority's concerns and address them up front, so your application is as ready for assessment as it can be.
Related services
- Car-Parking Demand AssessmentsA car-parking demand assessment works out how much parking your development actually needs — and provides the evidence to support a rate different from the standard planning requirement.
- Access Design and AssessmentsAccess design and assessment confirms that vehicles can safely enter and leave your site — and designs the crossover, driveway or intersection treatment to make it work.
- Swept-Path AnalysisSwept-path analysis uses vehicle-turning software to prove that the largest vehicles using your site can actually enter, manoeuvre and leave it safely.
- Traffic and Parking Data CollectionTraffic and parking data collection gathers the counts and surveys — turning movements, volumes, parking occupancy — that reliable transport analysis depends on.
Sectors & locations
Servicing Victoria and Queensland.
Representative work
Have a project that needs a clear way forward?
Tell us about your development and we'll set out the scope, deliverables and fee in writing.