16.2 Process
During the preliminary stages of permitting for a proposed development, TxDOT may recommend submission of a TIA. Typically, a TIA is performed when a proposed development is anticipated to generate 100 or more vehicle trips in a given peak hour with access to a TxDOT facility. It is recommended to use
Appendix Q, Section 1 – TIA Quality Control Checklist
during the TIA process to maintain consistency.16.2.1 TIA Categories
Confirm TIA categories with the local TxDOT District. If the District does not have guidelines for TIA categories, it is recommended to use Texas Transportation Institute’s (TTI’s) Recommended Access Management Guidelines for Texas (Report No. FHWA/TX05/0-4141-2). A TIA is classified into one of three typical categories based on the number of trips generated by the development as shown in . Developments that generate less than 100 trips and prompt minor engineering studies for access management purposes are also recommended to confirm that proposed driveways comply with TxDOT’s Access Management Manual. An
example
of determining peak hour trip generation is provided in Appendix Q, Section 3 – TIA Example Problems
.Categories | Peak Hour Trip Generation Range (veh/hr) | Additional Requirement | Analysis to Include |
|---|---|---|---|
1 | 100-499 | The TxDOT District can request a TIA if under 100 trips result from localized safety or capacity deficiencies. |
|
2 | 500-1,000 | NA |
|
3 | >1,000 | NA |
|
Note: Service drives, emergency drives, and other drives with minimal traffic are typically omitted. This table is adapted from TTI’s Guidelines.
16.2.2 Preliminary Scoping
It is recommended that the specific project scope be confirmed with the local TxDOT District before the start of a TIA. Whether with an in-person meeting or alternate correspondence, discussing the scope with TxDOT will tailor a TIA to each specific project. TIAs can vary significantly from one to another, and consulting TxDOT is important to check that nothing is overlooked in a project.
This correspondence can help confirm:
- Number of access points to TxDOT roadways;
- Acceptable LOS thresholds;
- Selected study years;
- Anticipated influence area;
- Intersections and roadways to be analyzed;
- Scenarios to analyze;
- Data collection method;
- Project schedule and buildout year;
- Data source;
- Use of TDM outputs, growth factors, etc.; and
- Other major projects in area
Once scope is confirmed with TxDOT, the TIA can be performed.
16.2.3 Authorship
It is suggested that the TIA be prepared and completed under the supervision of a professional engineer (P.E.) licensed in the State of Texas and that the P.E. have competence and experience in traffic engineering. It is also recommended that all aspects of the deliverable be completed in a professional and ethical manner and that the final submittal be signed, sealed, and dated.
16.2.4 TIA Report
It is recommended that a technical memorandum or report be compiled detailing the analysis completed and stating all findings and recommendations. Recommended TIA report deliverables are found in
Appendix Q, Section 2 – TIA Report Outline
. Coordinate with the TxDOT project manager for final report deliverables.16.2.5 Review and Approval
Once a TIA is completed, it is recommended that the document be signed, sealed, and submitted to TxDOT for review and approval. Coordinate with the local TxDOT District for specific submittal practices and deadlines. Comments received from TxDOT are typically addressed in a revised TIA.