It’s a common question asked by developers and property owners: Does our Fairfax County development project require a Traffic Impact Analysis (TIA)?
In 2025, Fairfax County updated its transportation analysis requirements for development applications, establishing four tiers based on the number of “net new average daily trips” generated by a proposed development.
Sometimes it’s easiest to see these things visually. So, our infographic provides a quick look at the four tiers, their trip-generation thresholds, and the role of FCDOT and VDOT in the transportation study process.
Want to Learn More About Fairfax County Traffic Impact Analysis Requirements?
For a closer look at the County’s updated requirements, visit our articles on:
- Part 1: Understanding CTA-Z Tiers 1 and 2
- Part 2: Understanding Tier 3 and Chapter 870
- Fairfax County Transportation Consultants
If you’re planning a development or redevelopment project in Fairfax County, our transportation engineers can help you understand which requirements may apply and what to expect as your project moves through the review process.