A DETECTION SYSTEM FOR FROST SNOW AND ICE ON BRIDGES AND HIGHWAYS

THE TWO-FOLD PROBLEM OF DETECTING FROST, ICE AND SNOW CONDITIONS ON THE DECK AREAS OF HIGHWAY BRIDGES AND OVERPASSES, AND PROVIDING SUITABLE WARNINGS TO MOTORISTS HAS BECOME AN INCREASINGLY IMPORTANT AND CRITICAL HIGHWAY SAFETY PROBLEM ON HIGH-SPEED INTERSTATE HIGHWAYS. THE AUTHOR DECRIBES A SYSTEM DEVELOPED BY HOLLEY CARBURETOR CO. THAT DETECTS THESE CONDITIONS THROUGH THE USE OF A COMBINATION AMBIENT AIR AND RELATIVE HUMIDITY SENSOR ON THE BRIDGE RAILING ALONG WITH TWO OTHER SENSORS BURIED IN THE BRIDGE DECK. THE RESULTS OF A THREE AND ONE-HALF YEAR EVALUATION PROGRAM OF THE SYSTEM THAT ACTUATES A FLASHING SIGN ON THE FLINT RIVER BRIDGE ON INTERSTATE 75 NEAR FLINT, MICHIGAN, ARE DESCRIBED. THE PAPER ALSO INTRODUCES A NEW DETECTION SYSTEM, DUAL-CHANNEL, FOR FROST, ICE AND SNOW. THIS SYSTEM SPLITS THE ANTICIPATORY FROST AND THE SNOW AND ICE SIGNALS INTO TWO SEPARATE SIGNALS. THE ANTICIPATORY SIGNAL CAN BE RELAYED AS AN EARLY WARNING TO ALERT MAINTENANCE STAFFS TO SEND AN OBSERVER TO EXAMINE THE CONDITIONS FIRST-HAND AND PASS A JUDGMENT ON THE NEED FOR CHEMICAL APPLICATION OR SIGN ACTUATION. THE EARLY WARNING SIGNAL CAN ALSO BE USED TO SWITCH-ON ELECTRIC HEATERS EMBEDDED IN THE DECK. THE SEPARATE ICE AND SNOW SIGNAL CAN BE USED TO ACTUATE A WARNING FLASHER. ALSO MENTIONED ARE TWO NEW APPLICATIONS OF THE DUAL-CHANNEL SYSTEM ON HIGHWAYS AND THE FIRST APPLICATION OF A SIMILAR SYSTEM ON AN AIRPORT RUNWAY. /AUTHOR/