The Houston-Galveston Area Council (H-GAC) is seeking proposals from qualified firms to provide on-call technical support and professional services for the maintenance, enhancement, development of sub-models and application to support H-GAC’s regional Travel Demand Model (TDM). The selected Contractor(s) will provide technical expertise to assist H-GAC staff in model or sub-model development, calibration, validation, troubleshooting, documentation, and application to regional planning projects.