Determining the Capacity Benefits of Real-time Signal Control at Intersections

Traffic responsive control strategies are increasingly being implemented to improve intersection performance. Critical intersection control (CIC) is using real-time traffic data to better assign green times to conflicting movements. However, the benefits of CIC have not been assessed, and existing methodologies for estimating intersection performance do not account for CIC or other traffic responsive control strategies. The effectiveness of CIC was evaluated at seven signalized intersections in the City of Los Angeles. The findings indicate that CIC generally improves traffic operations. The ongoing evaluation of additional test sites will result in guidelines and adjustment factors in estimating intersection performance under CIC using the Highway Capacity Manual and other analysis techniques. Key Words: Traffic Signals, Capacity, Level of Service, Critical Intersection Control (CIC)