Profitability is the key concern for transport companies. Costs are increased due to the rising fuel prices and technological investments. As well as new legal restrictions on the emission rates have forced the sector different fuel efficient technologies. Reducing weight is one of the most important methods of improving fuel efficiency and cutting CO2 emissions. Accordingly lighter, more fuel efficient, environmentally sustainable and safety vehicles are in the priority list of European authorities. And also the future of hybrid and electric vehicles depends on the lightweighting: The seat structure was chosen as the area for study which presented the best opportunity for weight reduction by the use of new materials. A seat provides comfort and safety of an occupant's while travelling. In the event of crash, the passenger seat is exposed many different forces. For this reason it should be designed sufficient strength and stiffness. Therefore an optimized seat design should be aesthetically pleasing, ergonomic, light and meet the safety requirements. Seats play an important role in mass of buses and coaches due to number of seats per vehicle. In this project, finite element analysis, together with topology and free-size optimization is used to design a lightweight passenger seat for new generation commercial vehicles. The seat CAD models were created with CATIA V5 and then imported into Hyper Mesh for finite element model creation and analysis. Results from the nonlinear analysis provide an accurate prediction of the material yielding and load path distribution on the seat structural frame components. In the end, the verification tests which were determined by ECE are applied the new seat and results were compared with the PEA results.