Passenger Car Equivalent Estimation Methods at Urban Signalized Intersections: A Systematic Review

This study presents a systematic review of Passenger Car Equivalency (PCE) at signalized intersections. The review focuses on comparing PCE calculation methods, examining PCE values across methods, and identifying the key influencing factors. Following the PRISMA methodology, 40 relevant studies were identified. The analysis revealed several critical calculation factors, including road geometry and vehicle composition. These studies employed seven major methods for PCE estimation: (1) headway ratio, (2) regression, (3) delay-based, (4) area occupancy, (5) queue-based, (6) capacity-based, and (7) optimization (Theil’s Coefficient). The findings indicate that PCE values vary substantially across studies, with motorcycle values ranging from −1.056 to 1.02, three-wheeler values from 0.22 to 1.51, and heavy vehicle values from 1.13 to 5.06. Cross-study comparisons revealed that this variation exists not only between countries but also between cities within the same country. This variability is attributed to traffic volume, traffic composition, approach width, and differences in driver behavior. The results support treating PCE as a dynamic parameter rather than static, as fixed values from national guidelines may not adequately represent local traffic conditions.