Long fiber thermoplastics (LFTs) have witnessed rapid growth in thermoplastics matrix composites, mainly due to developments in the automotive and transportation sector. In LFTs, pelletized thermoplastic polymer matrix is reinforced with long glass or carbon fibers (3-25 mm) are processed by extrusion-compression molding. The current work focuses on the applied science and manufacturing of E-glass/polypropylene (E-glass/PP) LFT composite material. Process simulation was conducted to evaluate the flow of fiber filled viscous charge during the compression molding of the LFT composite. Studies on optimum charge size and placement in the tool, press force, temperature of mold, shrinkage and warpage were also conducted. The flow pattern of the molten charge in the mold and the resulting fiber orientation predicted by process simulation are verified experimentally. The studies have been applied for a mass transit/transportation component namely, a LFT battery box access door for form-fit-function to replace a heavy metal door. Weight reduction of 60% was achieved using 40% weight percent E-glass/PP LFT over the metal design. © 2008 Elsevier Ltd. All rights reserved.