The thesis aimed to investigate the crashing behavior of locally manufactured 60 seated busrnstructural frames in case of frontal and side impacts. In addition to studying the crashworthinessrnof current structure, the most severe impact condition was identified by referring to crash testrnand an improvement on structure for a better crash performance for that impact condition wasrnproposed.rnA full frontal and an offset impact position were used for frontal impact testing while analysisrnfor side impact a perpendicular and angled/oblique impact position were used. Full-frontal crashrnanalysis was done according to the ECE-R29 involving a frontal crash pendulum test in whichrnimpacting energy is set to 55 kJ and safe space between steering model and manikin is checked.rnwhile for offset frontal impact a simulation of bus structure impacting a rigid wall with an initialrnvelocity of 56km/hr was done to check structures response to such kind of accidents. For sideimpact,rnresidual space specified on ECE-R60 was used to check side frame deformation in casernof perpendicular and angled/oblique impact. An impacting trolley with an initial speed of 48rnkm/hr was used for the side-impact test.rnCommercial software CATIA and ABAQUS were used for geometrical modelling and analysis.rnThe study focused on identifying the crashworthiness of the bus structure by analyzing thernstructural deformation, crash pulse, crash force efficiency, HIC, and energy absorbing capacity.rnThe results showed that the current structure had failed to meet regulation in the case of bothrnfrontal impacts and side perpendicular impact. In full frontal impact an intrusion of 17.32 mmrnin to manikin is seen and side frame has intruded residual space by 8.22 mm. Amongst the testsrnmost severe impact damages was observed in the case of full-frontal and off-set frontal crashrntests.rnFor improving crashworthiness of the structure, three models were proposed and testedrnaccording to ECE-R29, the first two were based on increasing the thickness of frames and thernlast was by adding a reinforcement profile. The simulation results for improved modelsrnshowed, by adding a reinforcement profile has improved the crashworthiness of the bus byrncreating a space between manikin and steering model of 36.33 mm structure and meets withrnregulation.