16.1 Introduction

16.1.1 Purpose and Intended Use

The purpose of conducting a TIA is to determine the ability of the surrounding transportation system to handle the change in demand of traffic introduced by a project. Improvements are recommended if the existing infrastructure does not sufficiently support the increased traffic demand. This chapter provides guidance on how to complete a TIA and discusses the pertinent information that is recommended to be included in all submittals.
It is recommended that a TIA:
  • Summarizes the report in an executive summary;
  • Documents the project area;
  • Details the proposed development;
  • Analyzes existing roadway conditions and traffic operations near the site;
  • Generates proposed site traffic using accepted trip generation rates in the ITE Trip Generation Manual;
  • Generates vehicle, pedestrian, freight, transit etc. site traffic data depending on project scope;
  • Formulates trip distribution and assignment for site-generated vehicular traffic;
  • Analyzes traffic operations and LOS at future key study years for the site;
  • Compares traffic operations between background scenarios and build scenarios;
  • Addresses access management;
  • Provides recommendations if mitigation is necessary; and
  • Summarizes findings

16.1.2 Limitations

This chapter does not provide final guidance as to whether a TIA is recommended. TxDOT and applicable agencies may request a traffic study for various scenarios that are not accounted for in this chapter. TxDOT’s Access Management Manual contains guidance in Chapter 3 on different engineering studies, including when TIAs are typically requested. A link to the TxDOT Access Management Manual can be found in
Appendix Q, Section 4 – External References (Reference 4)
. The TxDOT project manager has the final say for the methodology used on the project.