von Blanckenhagen, B., "Light Simulations: Controlling Stray-Light in the Headlamp," SAE Technical Paper 2008-01-0667, 2008, doi:10.4271/2008-01-0667.
SAE regulations require that the light emitted by a low beam in the region from 10° to 90° upwards has an intensity smaller than 125 cd. Therefore, the emission of stray-light has to be reduced by making the materials in the headlamp absorbing or diffuse scattering. In order to determine if a design fulfils the legal requirements, it is necessary to simulate virtual prototypes, which in turn requires the knowledge of the optical properties of the surfaces. It is shown, that a good agreement between stray light simulation and stray light measurement of the real headlamp can be achieved, if samples, which have been made in the same way the future part will be made, have been used to determine the optical properties.