Traffic Management Systems Performance Measurement: Working Paper #2

Traffic Data System Improvement Plans were prepared for Caltrans Districts 1 1 (San Diego) and 12 (Orange County) as part of a research project on performance measurement for traffic management systems. The plans document data system objectives, data requirements, and existing data collection and management systems; evaluate the adequacy of existing systems; identify improvements and resource requirements; and document the districts’ priorities for action. Both districts have similar data systems, although Orange County’s is better developed. Both systems rely heavily on single-loop detectors for traffic surveillance. Both either have or plan to have current- generation data display and management software, complete coverage of urban freeways by loop-detector systems, extensive video surveillance systems, and fiber-optic communication systems. In addition, both provide or will provide computerized incident and equipment-status logging, adequate accident and traffic volume data bases, and automatic data screening capability. Traffic data systems in the two districts appear to be generally adequate to support major performance measures identified in a previous phase of the project. Despite their commitment to providing sophisticated traffic data collection and data management systems, however, the two districts do not necessarily have a clear vision of how to use the data to monitor performance, and lack the organizational structure and staffing to carry out evaluation studies, performance monitoring, and data quality control.