This report describes a multi-year effort to simulate the Santa Monica Freeway Corridor in Los Angeles using the INTEGRATION computer simulation model, and to investigate the potential benefits of Intelligent Transportation Systems (ITS). The simulation process involved a massive data collection effort, coding the collected data into the model, testing, and calibration of the INTEGRATION model, and performing investigations with the calibrated network. Investigations were restricted to limited Advanced Traffic Information Systems (ATIS) studies with a modified morning peak period. Results indicated that ATIS benefits increased significantly with incident severity and significantly decreased with distorted information.