Do I need a Traffic Impact Analysis?

May 20, 2014 by Chance Terrian

Do I need a Traffic Impact Analysis?

(Answer specific for City of Austin projects)


intersectionA Traffic Impact Analysis (TIA) is a study which assesses the adequacy of the existing or future transportation infrastructure to accommodate additional trips generated by a proposed development, redevelopment or land rezoning.

In the City of Austin, TIA requirements apply to individual lots when an application is made to zone or rezone a lot or for site plan approval to develop the lot.

A determination as to whether a TIA is required must be made prior to submittal of a zoning, site plan, or subdivision application as appropriate.  This determination is made by the City of Austin Planning and Development Review Department. A TIA is provided through a civil engineer with traffic expertise at the cost of the project applicant.

In general, a TIA is required if the expected number of NET NEW trips generated by the project exceeds 2,000 vehicle trips per day. 

In a TIA analysis, credit is given for any existing development which already generates trips. The TIA trip generation calculations are done in accordance with the guidelines of the Institute of Traffic Engineers (ITE).

Trip Generation

Keep in mind that a Neighborhood Traffic Analysis (NTA) can be required if the project has access only to a residential local or collector street and the expected number of vehicle trips generated by the project exceeds 300 vehicle trips per day over the existing uses. A neighborhood traffic analysis is a simplified TIA that assesses the impact of a proposed project on residential streets. An NTA is limited to an evaluation of existing and projected operating levels of residential streets and an identification of measures needed to minimize the impact on traffic. The NTA is typically conducted by City Staff.

Click here for a free spreadsheet that can help you calculate your trip generation!

Do you have questions about how many multifamily units, homes, or how much commercial square footage will trigger a TIA? We can help! Contact us today at (512) 669-5560. 

Written by Chance Terrian

Chance Terrian

Chance Terrian takes pride in being one of the top CAD designers working in Texas. He has over 16 years of professional experience in civil engineering design, permitting and construction administration. That experience includes roadway design, water & sewer design, grading, drainage, pond design, cut & fill analysis, exhibits, details, sections, and everything else required for completing retail, multi-family, single family, and commercial projects in both public and private sectors. He’s also known around town for his unwavering attention to detail, natural talent for problem solving, and superior designs. In addition to his accomplishments in fully designed and breathtaking construction plans, he is also responsible for BIG RED DOG’s CAD standards, CAD training and implementation programs. With the help of our other Principal CAD experts, he has created the template that makes all of BIG RED DOG’s plans “The best looking plans in Land Development.”