Motorcycle Headlamp Distribution Comparison

The forward lighting systems on a motorcycle differ from the forward lighting systems on passenger cars, trucks, and tractor trailer. Many motorcycles, for instance, have only a single headlamp. For motorcycles that have more than one headlamp, the total width between the headlamps is still significantly less than the width of an automobile, an important component in the detection of a vehicle at night, as well as a factor in the efficacy of the beam pattern to help a driver see ahead. Single headlamp configurations are centered on the vehicle, and provide little assistance in marking the outside boundaries like a passenger car or truck headlamps can. Further, because of the dynamics of a motorcycle, the performance of the headlamp will differ around turns or corners, since the motorcycle must lean in order to negotiate a turn. As a result, the beam pattern, and hence visibility, provided by the headlamps on a motorcycle are unique for motorized vehicles. This paper measures the headlamp beam patterns of nine motorcycle headlamps. The type of motorcycles tested covers a variety of motorcycle styles and a variety of headlamp designs. Iso-illuminance diagrams are created from full scale tests and compared to each other. An additional discussion of the effect the roadway shoulder has on headlamp performance is also included.