In South Asian countries, traffic differs significantly in vehicle variety, driving behaviors, and traffic volumes compared to many other regions. Motorcycles (MCs) are prevalent and increasingly popular modes of transportation, reflecting rapid growth over time. MCs in Sri Lanka significantly influence traffic, safety, and environmental concerns, accounting for over 40% of annual fatal accidents. Erratic driving and a lack of lane discipline among MC riders disrupt traffic flow and contribute to emissions. Regulating MC behavior is imperative. This research aims to evaluate and measure the impact of MCs on urban traffic flow, considering their effects on road safety and congestion. Research employs camera devices to analyze MC dynamics at road sections and signalized intersections. The study concentrates on evaluating motorcycle impacts at mid-blocks and signalized intersections. It analyzes motorcycle trajectories, speeds, headways, and lane positions across different traffic scenarios. Furthermore, the research seeks to understand how motorcycles affect urban traffic, considering Passenger Car Unit (PCU) variations, saturation headway, and start-up lost time. PCU values for MCs range from 0.35–0.60 in low MC compositions and 0.40–0.75 in high compositions. MC presence at intersections increases saturation headway by 5.7 s and correlates positively with start-up lost time. Each MC adds 0.51 s to start-up lost time. The study aids in understanding MC driving behaviors and quantifying their traffic impacts, providing accurate PCU factors for different traffic conditions and compositions. Ultimately, this study would facilitate future studies on quantifying the traffic impacts of MCs on roads with similar characteristics.