Where data fits in a traffic impact study
A traffic impact study answers one question for a reviewing agency: what will this development do to the surrounding network. Every stage of that answer rests on existing-condition data. Trip generation is compared against observed volumes. Capacity analysis needs turning movements and a defensible peak hour factor. Queue and delay results are only as good as the intersection counts underneath them. If the base data is thin, the reviewer will find it.
We supply that base layer. Our clients are the transportation engineers and planners who write the study; we are the count operation behind it. You keep authorship, methodology and the seal — we make sure the numbers in the appendix hold up.
The data package for a typical TIA
- Turning movement counts at every study intersection, 15-minute bins, AM and PM peak periods (or full 12-hour where the agency requires it)
- Peak hour factor per approach and intersection, calculated not assumed
- Heavy-vehicle percentages by movement for HCM inputs
- Pedestrian and cyclist volumes by crosswalk for multimodal sections
- Driveway and access counts at the site and comparable existing generators
- Queue length observations where the agency asks for observed rather than modelled queues
- Seasonal or day-of-week comparison counts when a factor needs supporting
Formatted for the tools you already use
Counts arrive structured for direct import — Synchro, HCS, Sidra, LinSig, VISSIM or a spreadsheet model. Tell us the destination and we will format for it, including the movement naming convention your model expects, so nobody on your team spends an afternoon transposing columns.
When a development needs a study at all
Thresholds are set locally, not nationally. Many US jurisdictions trigger a study at a defined number of new peak-hour trips — often somewhere between 50 and 100 — or at a change of use, a new access onto an arterial, or a rezoning. Because the threshold is a trip count, the first honest step is usually a count, not a model. Our guide to traffic impact studies walks through the full sequence.
Working to an agency submission date?
Tell us the deadline first. We schedule backwards from the submission, not forwards from the purchase order, and we will say plainly if the window is too tight for the data to be credible.
Frequently asked
Do you write the traffic impact study itself?
No. We collect and process the data; the study, the methodology and the professional seal stay with your firm. That boundary is deliberate — it keeps you in control of the engineering judgement and the liability.
Which peak periods should be counted?
Most studies use a weekday AM and PM peak period of at least two hours each, plus a Saturday midday peak for retail. Some agencies specify 12-hour or 24-hour counts. Send us the agency's scoping letter and we will match it.
How much does traffic impact study data cost?
Cost is driven by the number of intersections, the hours counted per location and the classification detail required. Our guide to traffic study costs sets out realistic ranges and the variables that move them.
Can you count a comparable existing site for trip generation?
Yes. Driveway counts at an existing comparable generator are one of the strongest ways to support or challenge an ITE rate, and reviewers respond well to local observed data.
Related guides
Traffic Impact Study: A Complete Guide for 2026
A traffic impact study is the analysis a jurisdiction requires before approving a development that will add trips to the network. Here is what one contains, when you need it, and what it rests on.
Read the guide → Cost & procurementHow Much Does a Traffic Study Cost?
Almost nobody in this industry publishes numbers. Here are real ranges for counts, parking studies and full traffic impact studies, and the six variables that actually move the price.
Read the guide →Get a price for traffic impact study data
Send the site details and the periods you need counted. We will come back with a fixed price and a delivery date, usually the same working day.