Functional requirements for technical surfaces are constantly increasing in the automotive industry. These include: reducing noise, reducing friction, and guaranteed 100 percent measurements. There is also pressure to reduce production costs. Scattered light technology is ideally suitable to target all these factors in the automotive industry. The new roughness parameter Aq (recommended in VDA 2009) reacts particularly well to frictional properties. By simultaneously measuring waviness, the technology can track faulty components which could cause noise emissions.