Data Analysis for Bus Planning and Monitoring Systems Abstract: This synthesis will be of interest to transit agency managers, their schedule and operations planning staff, and others who are responsible for information about systems operations and ridership. It will also be of interest to others who interact with transit agencies in the reporting of operations data to support regular scheduling and operations planning activities for monitoring trends and reporting to oversight agencies. This synthesis reviews the state of the practice in how data are analyzed. It addresses methods used to analyze data and what computer systems are used to process and store data. It also covers accuracy issues, including measurement errors, and other problems, including errors in estimates. This TRB report addresses agency experience with different data collection systems, giving attention to management error, the need for sampling, and methods for screening, editing, and compensating for data imperfection. Sample reports from selected U.S. and Canadian transit agencies are reproduced in this synthesis.