Chapter 16 Traffic Impact Analysis
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.