RECOGNITION OF TRAFFIC-CONTROL SIGNS

THE PAPER INCLUDES A REVIEW OF PUBLISHED AND UNPUBLISHED LITERATURE WITH RESPECT TO SYMBOLS VERSUS WORD MESSAGES ON TRAFFIC SIGNS, SYMBOLIZATION PHILOSOPHIES AND RECOGNITION PROBLEMS, AND EDUCATION OF MOTORISTS ABOUT MEANINGS OF SYMBOLS. THE PAPER ALSO REPORTS ON A LABORATORY STUDY AND A FIELD STUDY OF TRAFFIC-SIGN RECOGNITION. THE LABORATORY EXPERIMENT WAS CONDUCTED TO DETERMINE THE ABILITY OF SUBJECTS TO RECOGNIZE SELECTED TURN-RESTRICTION SIGNS UNDER CONDITIONS OF SHORT EXPOSURE. THE TRAFFIC SIGNS WERE VARIED BY TYPES OF TURN RESTRICTIONS AND MODES OF INDICATING THE SIGN MESSAGE, I.E., WORDS, POSITIVE AND NEGATIVE SYMBOLS, AND COMBINATIONS OF TRESE. THE EXPERIMENT MADE USE OF A PROJECTION TACHISTOSCOPE. SUBJECTS VARIED IN AGE, DRIVING SKILL, AND EXPERIENCE. THE FIELD STUDY COMPARED THE EFFECTIVENESS OF BOTH NEGATIVE AND POSITIVE SYMBOLS. THE EFFECTIVENESS WAS MEASURED IN RELATION TO THE NUMBER OF MOTORISTS DISREGARDING THE TURN-RESTRICTION SIGN.