ANALYSIS AND PROJECTION OF RESEARCH ON TRAFFIC SURVEILLANCE, COMMUNICATION, AND CONTROL

RESEARCH WAS CONDUCTED TO EVALUATE THE STATE-OF-THE-ART OF TRAFFIC SURVEILLANCE, COMMUNICATION, AND CONTROL, AND TO SET FORTH GUIDE LINES FOR THE DETERMINATION OF RAPID-PAYOFF RESEARCH THAT COULD BE UNDERTAKEN THROUGH THE NATIONAL COOPERATIVE HIGHWAY RESEARCH PROJECT AND THE STATE HIGHWAY DEPARTMENTS. THE METHOD USED TO DETERMINE THE RECOMMENDED PROGRAM OF RESEARCH WAS TO DIGEST AND INTERPRET ALL PERTINENT LITERATURE, FOLLOWED BY FIELD VISITS TO STUDY THE EXPERIMENTS, TO ARRIVE AT SUBJECTIVE EVALUATIONS BASED ON THE INVESTIGATOR'S TRAFFIC ENGINEERING EXPERIENCE. THE ANALYSIS OF CURRENT RESEARCH INCLUDES FREEWAY CONTROL, SYSTEM CONTROL OF TRAFFIC SIGNALS, COMMUNICATION BETWEEN VEHICLES, AND OTHER TRAFFIC SYSTEMS RESEARCH. THE MOST IMMEDIATELY PROMISING DEVELOPMENT IN THE FIELD OF TRAFFIC SURVEILLANCE AND CONTROL IS THE CONCEPT OF FREEWAY RAMP CONTROL BEING PRACTICED IN HOUSTON, CHICAGO, DETROIT, AND LOS ANGELES ON SHORT SECTIONS OF CONGESTED URBAN FREEWAYS. THE PRINCIPLE USED IS TO CONTROL THE RATE AT WHICH VEHICLES CAN ENTER THE FREEWAY, BY STOP-AND-GO SIGNALS ON THE ENTRANCE RAMPS, SO THAT THE CAPACITY OF THE FREEWAY DOWNSTREAM OF THE ENTRANCE IS NOT EXCEEDED. AREA CONTROL OF TRAFFIC SIGNALS ESSENTIALLY DEPEND ON A LIBRARY OF PRE- ENGINEERED CONTROL STRATEGIES. EXCEPT IN GLASGOW, WHERE SOME NEW CONCEPTS ARE BEING TRIED, THESE STRATEGIES CONSIST OF VARIATIONS IN CYCLE LENGTHS, SPLITS AND OFFSETS. THE COMPUTER SELECTS AND EXECUTES ONE OR MORE OF THESE STRATEGIES ON THE BASIS OF CURRENT INFORMATION ABOUT TRAFFIC RECEIVED FROM SEVERAL HUNDRED DETECTORS PLACED THROUGHOUT THE NETWORK. OHIO STATE UNIVERSITY RESEARCH IS REPORTED ON INSTRUMENTS MOUNTED IN VEHICLES THAT INFORM A FOLLOWING DRIVER OF HIS RATE OF CLOSURE AND, WHEN HE IS CLOSE, THE APPROXIMATE DISTANCE TO THE CAR AHEAD. THE LEADING CAR TRANSMITS AN INFRARED SIGNAL WHICH IS CHOPPED AT A FREQUENCY PROPORTIONAL TO THE SPEED, AND THE FOLLOWING CAR RECEIVES THIS SIGNAL AND COMPARES IT WITH ITS OWN SPEED IN AN ELECTRONIC DEVICE. THE OUTPUT IS A CURRENT THAT CAUSES A CALIBRATED GALVANOMETER IN THE FOLLOWING CAR TO REGISTER THE DIFFERENCE IN SPEEDS. THE IMPROVEMENT AND STANDARDIZATION IS RECOMMENDED OF REAR-END LIGHTING SYSTEMS ON VEHICLES. A TABULATION IS PRESENTED OF SPECIFIC RESEARCH NEEDS IN THE AREA OF TRAFFIC SURVEILLANCE, COMMUNICATION, AND CONTROL.