Abstract

A motorcycle headlamp capable of emitting a light beam with a beam pattern calculated to provide optimum forward illumination. In order to maintain the beam pattern in a level position about the lamp axis despite the lateral tipping of the motorcycle, at least one road sensor is employed for detecting the lateral angular position of the vehicle with respect to the road surface by transmitting radiation such as an ultrasonic wave or infrared rays toward the road surface and receiving its reflection from the road surface. Electric signals representative of lateral vehicle inclinationare fed to a central processor unit, which then causes energization of a reversible electric motor built into the headlamp unit for leveling the beam pattern by revolving the bulb and control lens of the headlamp unit relative to the lamp housing. Thus, as the lateral angular position of the vehicle is detected in reference to the road surface, instead of to the perpendicular, the beam pattern can be maintained in the level position with respect to the road surface regardless of whether the road is banked or unbanked. Several different methods of detecting lateral vehicle inclination are disclosed.