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

Within the City of San Antonio, 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.

In Travis County and Bexar County, TIA requirements apply to parcels for any type of development application. 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 Development Services Department. A TIA is provided through a civil engineer with traffic expertise at the cost of the project applicant.

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

In Travis County, a TIA is required if the expected number of NET NEW trips generated by the project exceeds 1,000 vehicle trips per day.

In the City of San Antonio and Bexar County, a TIA is required if the expected number of NET NEW trips generated by the project exceeds 75 vehicle trips per highest trip generating peak hour.

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).

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.

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 to speak with one of our engineers about your project.