Vehicle accidents are happening every day. Most drivers are convinced that they can avoid such Trouble some situations. Nevertheless, we must take into account that ten thousand dead and hundreds of thousands to million wounded each year. These numbers call for the necessity to improve the safety of automobiles during accidents. Hence the main aim of this project is to conduct finite element analysis and to optimize the design and energy absorption of S-shaped longitudinal member having different cross section such as square, square with inner stiffener and square with double inner stiffener. The S-shaped longitudinal member is made up of Aluminum grade 6063-T5. For Aluminum grade 6063-T5 material having square with double inner stiffener cross section absorbing maximum energy we conclude that square with double inner stiffener cross section is very good at safety of the structure and operator compartment of vehicle.