The Texas Trip Distribution Models is a collection of computer programs designed to perform trip distributions featuring the application of either a constrained interactance model or the Atomistic Model. Other programs available in the package provide full support. The purpose of this manual is to provide users with operating instructions for the Texas Trip Distribution Models. Cross references for significant variables and arrays used in the package and formats for all data sets and data cards associated with the package are provided. This report is part of an on-going research project between the Texas Transportation Institute and the Texas Department of Transportation. It is a major update of the Program Documentation Manual for the Texas Trip Distribution Models.