The LONG (Longitudinal Oriented Normative time Gap compensation) concept describes a lighting system that enhances the conspicuity of motorcycles by enhancing the ability of oncoming drivers to evaluate the distance and speed of a motorcycle equipped with lighting in the LONG configuration. It is based on the hypothesis that a motorcycle observed at the same distance and speed as an automobile may be perceived farther away and traveling more slowly than the automobile, because of the motorcycle’s higher lamp location and narrower lighting layout compared with that of an automobile. To address this the LONG configured are spread farther apart along a vertical axis compared to the relatively tightly grouped lighting layout found on a typical motorcycle. Knowledge of cognitive psychology is applied to the LONG system. To test the hypotheses behind the LONG concept, it has been evaluated by measuring critical time gap in right-turn across path scenario (in left traffic right-of-way countries). It is shown that motorcycles with the system have conspicuity on a level comparable to automobiles by measuring critical time gaps of about 20 experimental subjects. The effects of both the layout of the lighting and luminous intensity dependence are also reported.