This is a summary of the results of Phase I for this project. It recommends a two-tiered congestion monitoring system for use in the State of Washington. In uncongested areas of the state it recommends use of volume/capacity ratios to estimate congestion levels. For congested roads, travel time measures are recommended. In addition to these measures, additional data items (mode choice, vehicle volumes, average vehicle occupancy, etc.) are also needed to measure congestion.