DYNAMIC ASPECTS OF MOTORWAY TRAFFIC SAFETY

IN A CURRENT RESEARCH PROGRAMME AT THE DELFT UNIVERSITY OF TECHNOLOGY AND SWOV INSTITUTE FOR ROAD SAFETY RESEARCH, AN ADAPTIVE CONTROL STRATEGY FOR THE MOTORWAY SYSTEM IS BEING DEVELOPED. THE PURPOSE OF THE SYSTEM IS TO OPTIMIZE TRAFFIC FLOW UNDER SAFE CONDITIONS. THIS PAPER DESCRIBES HOW SAFETY IS INCORPORATED INTO THE SYSTEM. THE CENTRAL FOCUS IS ON TRAFFIC BEHAVIOUR. TRAFFIC DATA DERIVED FROM DETECTION LOOPS IN THE ROAD SURFACE FORM THE BASIS FOR A QUANTITATIVE DESCRIPTION OF THE TRAFFIC SITUATION. THESE DATA ARE COMPARED TO A TRAFFIC REFERENCE MODEL WHICH INTERPRETS THE SAFETY OF THE SITUATION. THESE DATA ARE COMPARED TO A TRAFFIC REFERENCE MODEL WHICH INTERPRETS THE SAFETY OF THE SITUATION ON THE BASIS OF A SET OF SAFETY CRITERIA. ON THE BASIS OF THIS INTERPRETATION, ACTION MAY BE TAKEN TO CHANGE TRAFFIC FLOW CONDITIONS, BY REDUCING SPEED OR BY INCREASING FOLLOWING DISTANCES BETWEEN VEHICLES. THE SAFETY CRITERIA ARE A RESULT OF EXTENSIVE RESEARCH, COMBINING SEVERAL METHODS INCLUDING VIDEO ANALYSIS, EXPERT OPINION RESEARCH AND MEASUREMENT OF MENTAL LOAD OF DRIVERS. THE PAPER BRIEFLY DESCRIBES THESE METHODS. IT ALSO SHOWS THAT QUANTIFICATION OF TRAFFIC SAFETY CHARACTERISTICS TAKES TIME, ALTHOUGH QUALITATIVE INTERPRETATIONS OF TRAFFIC SAFETY ARE EASY TO GENERATE. (A) FOR THE COVERING ABSTRACT OF THE CONFERENCE SEE IRRD 860351.