A ladar sensor with a field of view and a vehicle lamp housed within a common envelope and mounted to a vehicle, said vehicle lamp with an illuminating pattern, and said envelope with at least one transparent face capable of transmitting visible wavelengths of light and infrared laser light, said ladar sensor comprising: a pulsed laser transmitter having a pulsed light output and diffusing optic for illuminating a scene in the field of view of said ladar sensor; a two dimensional array of light sensitive detectors positioned at a focal point of a light collecting and focusing lens, each of said light sensitive detectors producing an electrical pulse when illuminated by a reflected portion of the pulsed light output; an electrical circuit connected to each light sensitive detector output adapted to amplify and detect said electrical pulse, said electrical circuit having a detected pulse output; and a timing circuit connected to each detected pulse output; said timing circuit further connected to a reference signal indicating the start time of said pulsed light output; said timing circuit producing an elapsed time signal indicating the time delay between the start time of the said pulsed light output and an electrical pulse indicated by said detected pulse output from said electrical circuit, wherein said automotive lamp includes: at least one visible light source with a visible light output beam; and at least one visible light transmitting optical element (23, 21) for conditioning said visible light output beam to create said illuminating pattern, characterised in that: a retro-reflector post is attached to said at least one transparent face of said common envelope which causes a sample of said pulsed light output to fall on at least one of said light sensitive detectors to define said reference signal; and a retro-reflecting layer is applied to the exterior of the said at least one transparent face of said common envelope in line with the retro-reflector post, wherein the height of said retro-reflector post and its non-unity index of refraction is configured to create an additional delay over the thin sections of said transparent envelope, thus making the retro-reflected optical signal from said retro-reflecting layer occur later in time than the undesired retroreflections from any materials adhered to the exterior surface of transparent envelope in use. a pulsed laser transmitter having a pulsed light output and diffusing optic for illuminating a scene in the field of view of said ladar sensor; a two dimensional array of light sensitive detectors positioned at a focal point of a light collecting and focusing lens, each of said light sensitive detectors producing an electrical pulse when illuminated by a reflected portion of the pulsed light output; an electrical circuit connected to each light sensitive detector output adapted to amplify and detect said electrical pulse, said electrical circuit having a detected pulse output; and a timing circuit connected to each detected pulse output; said timing circuit further connected to a reference signal indicating the start time of said pulsed light output; said timing circuit producing an elapsed time signal indicating the time delay between the start time of the said pulsed light output and an electrical pulse indicated by said detected pulse output from said electrical circuit, said timing circuit further connected to a reference signal indicating the start time of said pulsed light output; said timing circuit producing an elapsed time signal indicating the time delay between the start time of the said pulsed light output and an electrical pulse indicated by said detected pulse output from said electrical circuit, wherein said automotive lamp includes: at least one visible light source with a visible light output beam; and at least one visible light transmitting optical element (23, 21) for conditioning said visible light output beam to create said illuminating pattern, at least one visible light source with a visible light output beam; and at least one visible light transmitting optical element (23, 21) for conditioning said visible light output beam to create said illuminating pattern, a retro-reflector post is attached to said at least one transparent face of said common envelope which causes a sample of said pulsed light output to fall on at least one of said light sensitive detectors to define said reference signal; and a retro-reflecting layer is applied to the exterior of the said at least one transparent face of said common envelope in line with the retro-reflector post, wherein the height of said retro-reflector post and its non-unity index of refraction is configured to create an additional delay over the thin sections of said transparent envelope, thus making the retro-reflected optical signal from said retro-reflecting layer occur later in time than the undesired retroreflections from any materials adhered to the exterior surface of transparent envelope in use.