A roundabout is a particular kind of intersection where vehicles circle around a center island. Compared to conventional intersections, roundabouts are intended to increase safety by lowering the risk of head-on crashes and the severity of collisions. Drivers, while entering a roundabout, should slow down and yield to traffic already in it and keep an eye out for pedestrians and cyclists. Each driver perceives critical gaps differently, and the entrance width, circulation width, and inscribed circle diameter all affect the minimal allowable gap. It's essential to calculate the critical gap, considering geometric elements such as the inscribed circle diameter, entry angle, and vehicle composition. A videographic survey, utilizing a camera in Karimnagar town, was conducted at three roundabouts, employing Raff's method to determine the critical gap. Results showed the Bus Stand Roundabout had the highest critical gap due to substantial bus traffic. Additionally, the critical gap values for each vehicle class were assessed, revealing that two-wheelers had the smallest critical gap values.