A range of legislative and policy changes over the last several years have significantly altered the requirements for State transportation planning and programming, necessitating substantial improvement in travel forecasting and modeling practices to support a new mission and increased responsibilities.  These changes included SB 375 (sustainable community), SB 743 (CEQA reform), SB 391 (California Transportation Plan), and Map 21 (California Freight Mobility Plan) that require more robust quantitative and analytic evaluation to describe the relative performance of transportation policies, strategies and programs.  The emphasis on system planning products such as the Interregional Transportation Strategic Plan (ITSP), interstate rail and freight movement demands an integrated multimodal approach to system planning which necessitates travel behavior data analysis and travel demand.   Since the passage of AB 32 in 2006 and subsequent passages of SB 375, SB 391 and MAP 21, Caltrans has been developing state-of-the-practice travel demand modeling tools to support theses legislations.  The California Statewide Travel Demand Model (CSTDM) and the California Statewide Freight Forecasting Model (CSFFM) are modeling tools that will assist in developing strategies to reduce Greenhouse Gas (GHG) emissions to support the Administration’s goals and targets.  In order to maintain state-of-the-practice tools, adequate truck data is needed to improve and enhance the CSTDM and the CSFFM to provide meaningful analysis for Caltrans freight projects. The California Truck Data Collection Improvement Project will restore operations of the Truck Activity Monitoring System (TAMS).  A subset of the existing sites will be selected for full lane-coverage expansion to ensure that all trucks are captured at those locations.  In addition, this study will explore the integration of additional data sources with TAMS to provide truck trip activity data.  This investigation has the potential to provide a better understanding of truck trip patterns by industry, which can further validate the truck trip matrices and route assignment of the CSFFM. The data generated from this study will be utilized for calibration and validation of the next update of the CSTDM and CSFFM which will be used by Caltrans Headquarters and Districts, Metropolitan Transportation Agencies, Regional Transportation Planning Agencies, other State agencies such as the California Air Resources Board and the California Energy Commission. This data will also be used to enhance and update existing planning databases within Caltrans.