EFFECTIVENESS OF REFLECTORIZED HEADLAMPS

ONE HAZARD ASSOCIATED WITH NIGHT DRIVING IS THE PROBLEM OF ENCOUNTERING VEHICLES WITH ONLY ONE LIGHTED HEADLAMP. RECENT INVESTIGATION INTO THE ONE-EYED VEHICLE PROBLEM LED TO THE PROPOSED USE OF REFLEX-REFLECTIVE MATERIALS INCLUDED WITHIN A HEADLAMP TO ACT AS A SAFETY DEVICE. SHOULD HEADLAMP FAILURE OCCUR, REFLECTED LIGHT WOULD PERMIT EARLY DISCRIMINATION OF THE UNLIT LAMP POSITION, THUS AFFORDING POSITIVE VEHICLE DELINEATION. A HEADLAMP OF THIS TYPE WAS DEVELOPED WHICH PROVIDES 6.9 CANDLEPOWER PER INCIDENT FOOTCANDLE PER UNIT AT 0.2 DEGREES DIVERGENCE AND 0 DEGREES INCIDENCE, SOMEWHAT HIGHER THAN THE MINIMUM VALUE OF 4.5 CANDLEPOWER PER FOOT-CANDLE VALUE SPECIFIED FOR CLASS A RED REFLEX-REFLECTORS BY THE SOCIETY OF AUTOMOTIVE ENGINEERS FOR IDENTICAL CONDITIONS. FINDINGS ARE REPORTED OF A RESEARCH STUDY DESIGNED TO EVALUATE THE EFFECTIVENESS OF THE REFLECTORIZED HEADLAMP UNDER REALISTIC NIGHT DRIVING CONDITIONS. THE ESTABLISHED PARAMETER WAS THE DISTANCE AT WHICH THE UNLIT SIDE OF AN APPROACHING ONE-EYED CAR COULD BE DETECTED FOR VEHICLES EQUIPPED WITH CONVENTIONAL HEADLAMPS AND FOR VEHICLES EQUIPPED WITH REFLECTORIZED HEADLAMPS. VARIABLES CONSIDERED WERE DRY AND SIMULATED RAIN CONDITIONS, THREE RATES OF CLOSURE, AND BOTH SIDES OF THE VEHICLE. MEAN DETECTION DISTANCES ESTABLISHED WERE 472 FT AND 288 FT FOR THE REFLECTORIZED AND CONVENTIONAL HEADLAMP CONDITIONS RESPECTIVELY. COMPARISON OF DETECTION DISTANCES OBTAINED FOR REFLECTORIZED HEADLAMPS TO MOTORIST PERCEPTION-REACTION DISTANCE ESTABLISHED A SIGNIFICANT IMPROVEMENT IN TIME AVAILABLE FOR EVASIVE ACTION.