Update — May 2026: the ITA Scoping Tool described at the end of this article is now live. Open the ITA Scoping Tool →
An Integrated Transport Assessment is the document that lets a development proposal land on the network without breaking it. At resource consent time, the ITA is what tells the council whether the proposed 400 lots will overwhelm the school zone at 8:15 am, whether the new commercial site will require a signalised intersection that isn’t in the LTP, whether the active-mode connections are credible.
Most ITAs we review fall into one of two failure modes.
Mode 1: the ITA stops at the gate. Trip generation rates from the RTA / NZTA database, peak-hour assignment, intersection capacity check at the immediately-adjacent intersection, parking calculation per the district plan, statement of compliance. Document signed off. Network context: zero.
Mode 2: the ITA over-shoots. Full microsimulation, multi-year forecast, mode-share modelling, regional model run. Document is 200 pages. Council reviewer takes three weeks. Cost to applicant is large. And the actual transport question — does this work — is buried.
A good ITA sits between those two. It does seven things. None of them are optional.
1. State the development clearly enough that the assessor can re-run it
The ITA opens with the development scope — number of lots / m² of commercial / school role / number of beds — in terms specific enough that the assessor can re-derive the trip generation. “Up to 400 dwellings” is not specific enough. “350 dwellings split 60% three-bed / 40% two-bed, plus a 1,200 m² convenience commercial component” becomes specific enough.
The point isn’t the precision — it’s the auditability. A council reviewer or a future ITA on the same site needs to be able to ask “what did they assume, and was that reasonable” and get an answer.
2. Set the trip generation against a defended source
The default is the NZTA / RTA Trips and Parking Database — that’s the sensible starting point. The ITA needs to state which rates it’s using, why those rates fit this development, and what sensitivity it ran around those rates.
The most common cut is the fitted rate vs the average rate. For residential, the fitted rate accounts for dwelling size and tenure mix; the average rate is a single number across all residential. Using the average rate on a high-occupancy site under-counts; using the fitted rate on a low-occupancy site over-counts. Stating the choice — and the +/- 10% sensitivity around it — is what makes the trip generation defensible.
3. Assign the trips to the actual network, not the obvious one
The trips don’t all funnel through the immediately-adjacent intersection. They distribute across the network according to where people are actually going. The ITA needs to use a distribution that reflects the local origin-destination pattern — pulled from the regional transport model where one exists, or built from journey-to- work census data and Google trip-time matrices where it doesn’t.
Where the trips land matters as much as how many of them there are. A 400-lot development generates the same trips whether they all turn left or all turn right, but the network impact is wildly different.
4. Test the network at the second-order intersection too
The first-order test is the immediately-adjacent intersection. The second-order test is the next intersection down each likely route — where the trips arrive at after a few minutes of travel. If the first-order intersection passes and the second-order intersection fails, the development still has an unsolved problem.
We’ve seen too many ITAs that test the development access onto the arterial, find capacity, and stop. The arterial intersection two blocks south then runs over capacity. The ITA passed; the network didn’t.
5. Test the active-mode connections, not just say they exist
The active-mode section of an ITA is usually a paragraph that says “the site is well-connected to footpaths and a nearby cycle lane”. That’s not an assessment. The assessment is: what’s the actual walking time from each lot to the nearest school, supermarket and bus stop? What’s the cycle journey distance to the town centre, and is it on protected infrastructure or shared with traffic? Where do the active-mode trips connect into the wider network, and is that network credible?
Active-mode is where the ITA earns or loses its credibility with councillors who are tired of “this development will support mode shift” claims that turn out to mean nothing on the ground.
6. Make the safety case as explicit as the capacity case
Capacity gets all the airtime in ITAs because intersection capacity is what fails first numerically. Safety usually gets a paragraph saying “no crash record at the access point” and that’s it.
A good ITA brings the safety question forward. What’s the crash history on the corridor the development feeds into? Where are the existing speed-management interventions? Does the development access introduce new conflict points? What’s the school-zone proximity? Is there a Safe System gap that the development should help close rather than worsen?
This is more work. It’s also where the ITA does the work that the RCA actually needs to make a consent decision.
7. Be explicit about what’s not in scope
The ITA needs an “out of scope” section. Things like: regional model re-run, long-term cumulative impact across all consented developments, freight-route assessment, public-transport reconfiguration. These are sometimes appropriate to defer to a different document; sometimes they need to be done. Either way, the ITA needs to say which it is.
The most useful ITAs we’ve reviewed include a short statement: “if this development triggers any of [X], that triggers a re-scoped ITA or a separate assessment”. That gives the council reviewer a clear hand-off rather than a silence to interpret.
The ITA scoping tool
The pattern across the seven items above is that the scoping of an ITA — what to assess, against what data, at what intersection horizon — drives whether the document is useful. If the scoping is right, the assessment is straightforward. If the scoping is wrong, no amount of modelling rescues it.
TTAP has built a scoping tool that asks structured questions about a proposed development (lots, m², location, road class, ADT, school proximity, timing) and produces a one-page scoping brief that covers what an ITA on that development should include — at what intersection horizon, against which data sources, with which active- mode and safety questions explicit.
The shape is simple: fill in the form, get a PDF brief that you can take to your own planner, or hand to us as the scope of the actual assessment. Open the ITA Scoping Tool →
If you have an upcoming development and aren’t sure what an ITA should actually cover, run it through the ITA Scoping Tool and bring the brief to the conversation — or talk to us and we’ll scope it with you.