In the automotive manufacturing industry increasing standards of crash protection for occupants are constantly being demanded by consumers backed up by legislation. In particular, increased rigidity of the passenger compartment is being demanded. Increased stiffness of the vehicle is also highly desirable to improve handling characteristics on the road and to reduce vibrations which lead to squeaks and rattles. These goals are difficult to achieve within the constraints of the lighter vehicle masses being required for improved fuel economy and exhaust emissions.

There is thus a pressing need to strengthen parts of automobiles such as chassis rails, pillars and anti-intrusion channels in doors without substantially increasing vehicular weight.

There are many examples in today's automotive industry where car manufacturues increase the strength of automobile structural members by filling or partially filling them with rigid Expanded PolyPropylene foam mouldings.

The use of Expanded PolyPropylene and Polystyrene has been considered preferable to non-foamed materials in order to reduce both weight and the cost of materials. Its is also preferred from an environmental standpoint due to it's recyclability and it’s zero rating for both ODP (Ozone Depletion Potential) and GWP (Global Warming Potential).