The Texas Department of Transportation is considering the upgrade and improvement of Interstate 35 (IH-35) in the Austin area. Study 7-1953 was directed toward providing assistance to the Austin District to analyze IH-35 design alternatives. The Texas Transportation Institute assisted the District in reviewing the designs and integrating high occupancy vehicle (HOV) lanes in the designs. To support the IH-35 analyses, time-of-day travel models were developed and implemented to support peak-period analyses. The Texas Mezzo-Level HOV Carpool Model was also implemented and applied for the IH-35 analyses. Detailed networks were coded and assigned for the various design alternatives. The purpose of this report is to document the model developed, implemented, and applied in the analyses of the IH-35 design alternatives.