THIS IS A CONTINUATION OF THE INVESTIGATION INTO RELATIONSHIPS BETWEEN ACCIDENT RATE AND HOURLY TRAFFIC FLOW AS OUTLINED IN PART I OF THE RESEARCH. THE UNDERLYING STUDY ATTEMPTS TO DETERMINE APPROPRIATE MODELS FOR SINGLE- AND MULTI-VEHICLE ACCIDENT RATES IN CONJUNCTION WITH FREE-FLOW AND CONGESTED-FLOW CONDITIONS. FOR THE FREE-FLOW DATA, THE TOTAL ACCIDENT RATE-HOURLY FLOW CURVE FOLLOWS THE U-SHAPED CONFIGURATION. THIS FORM IS THE RESULT OF A CONVEX DOWNWARD AND A CONVEX UPWARD CURVE FOR SINGLE- AND MULTI-VEHICLE ACCIDENTS, RESPECTIVELY. FOR THE CONGESTED-FLOW DATA (CHARACTERIZED BY MULTI-VEHICLE ACCIDENTS), THE ACCIDENT RATE INCREASES SHARPLY WITH HOURLY FLOW. THE MODELS ARE APPLIED TO PROBABILISTIC ASPECTS WITH CONSIDERATION OF A FITTED, GENERALIZED (HOURLY FLOW DEPENDENT) HEADWAY MODEL. THE HEADWAY MODEL REPRESENTS THE PROBABILITY THAT TWO VEHICLES WHICH ARE, EVEN INSTANTANEOUSLY, UNDER A CAR-FOLLOWING MODE ARE IN A POTENTIALLY HAZARDOUS SITUATION. THE APPROACH INVESTIGATED IS BELIEVED TO PROVIDE AN ESSENTIAL INPUT FOR BOTH SIMULATION STUDIES AND THEORETICAL MODELS OF ROAD TRAFFIC ACCIDENTS. (Author/publisher).
Samenvatting