The fuel efficiency of a vehicle depends on multiple factors such as engine efficiency, type of fuel, aerodynamic drag, and tire friction and vehicle weight. Analysis of weight and functionality was done, to develop a lightweight and low-cost Roof rack rail.The Roof rack rail is made up of a lightweight material with thin cross section and has the design that allows the fitment of luggage carrier or luggage rack on the car roof.In starting this paper describes the design and weight contribution by standard Roof rack rail and its related parts.Secondly, the selection of material within different proposed options studied and a comparison of manufacturing and design-related factors.Thirdly, it has a description of the design of Roof rack rail to accommodate the luggage carrier fitment on the car roof. Moreover, optimizations of Roof rack rail design by continuous change in position, shape, and parts used.Finally, the detail of the lightweight and cost effective Roof rack rail design. Cause and countermeasure detail of the surface defects occurred in parts during mass production. Moreover, a realization of value engineering of 70% in the above-mentioned new Roof rack rail.