AN INVESTIGATION OF SIX COMMON TRAFFIC CONTROL TREATMENTS EMPLOYED AT ROADWORK SITES WAS UNDERTAKEN TO TEST THEIR INFLUENCE ON DRIVER BEHAVIOUR. THE EFFECTIVENESS OF THE VARIOUS TREATMENTS WAS MEASURED IN TERMS OF THEIR ABILITY TO REDUCE SPEED PAST THE ROADWORKS WITHOUT ADVERSELY AFFECTING SPEED DISTRIBUTION WITHIN THE TRAFFIC STREAM. ALL TESTS WERE CARRIED OUT ON AN OPEN RURAL ROAD WITH GOOD SIGHT DISTANCE. THE ROADWORKS NECESSITATED THE CLOSURE OF HALF OF ONE TRAFFIC LANE. THE RESULTS OF THE TRIALS SUGGEST THAT, AT A CLEARLY VISIBLE WORK SITE, A MAJOR INFLUENCE ON VEHICLE SPEEDS PAST THE WORKS IS THE WORK ACTIVITY ITSELF. SIGNS IN PRACTICE FURTHER REDUCED SPEEDS IN THE UNOBSTRUCTED LANE BUT SIGNING TO FULL AS 1742 REQUIREMENTS RESULTED IN NO SIGNIFICANT CHANGE IN SPEED FROM EITHER SIGNS IN PRACTICE OR THE 'NO SIGNS' TEST CONDITIONS; IT REQUIRED THE ADDITION OF A 60 KM/H WORKS SPEED LIMIT TO PRODUCE SIGNIFICANT REDUCTION IN SPEED WHEN COMPARED TO THE MINIMUM LEVELS OF CONTROL TESTED. THE EFFECT OF THE 60 KM/H LIMIT WAS A MARGINAL SPEED REDUCTION FROM THE AS 1742 CONDITION INTO WHICH IT WAS INTRODUCED, AND THERE IS SOME EVIDENCE TO SUGGEST THAT NOT ALL DRIVERS APPRECIATE THE REGULATORY NATURE OF ROADWORK SPEED LIMITS. APART FROM THE INITIAL PRESENCE OF THE WORKS PLANT AND PERSONNEL, IT WAS ONLY THOSE CONTROL TREATMENTS WHICH CONTAINED AN ELEMENT OF DRIVER SURVEILLANCE (FLAGMEN AND POLICE) WHICH RESULTED IN FURTHER REDUCTIONS IN VEHICLE SPEEDS PAST THE SITE (A). THE NUMBER OF THE COVERING ABSTRACT OF THE CONFERENCE IS IRRD NO 255423.
Samenvatting