his research presents the numerical investigation of the dynamic response of bus structure by optimizing the frame size. The study is very important to fill the gap in the area of vehicle structure response due to maneuverability. Here it is aimed to optimize the weight of bus body structure by evaluating its stress and deformation. The study worked at Bishoftu bus model ZK6118HGA, modeled with solid work 18 and analysis has been done with ANSYS 19.0. Braking left corner, and right cornering test has been performed. Optimization has been done by replacing overdesigned RHS (rectangular hollow section) with lower-sized RHS. The improved structure was also investigated with the cornering and braking tests. The weight of the improved structure is significantly lower than the original structure. The study revealed that the weight of the bus body structure was reduced by 93.58 kg. Which is about 3.07% of the whole structure weight. The procedure used for the analysis is validated using analytical calculations on simply supported overhanging beam comparing to software verification.