Abstract: The present disclosure provides a lighting system having elongated lightguides disposed in elongated optical cavities that exhibit a uniform surface emission, a vehicle light assembly using the lighting system, and automotive exterior lamps incorporating the vehicle light assemblies. In one particular embodiment, the lighting system includes an elongated lightguide disposed in a reflective elongated optical cavity. The reflective elongated optical cavity can include a diffuse output surface, and the lighting system can have one or more LEDs positioned to inject light into the elongated lightguide.