THE PAPER IS AN ADDITION TO A RECENT REFORMATION MODEL BY ELSE, PUBLISHED IN THE JOURNAL (1981), FOR DETERMINING THE MARGINAL SOCIAL COST OF ROAD TRAFFIC. IT DEALS WITH LONGER ROADS BY DIVIDING THEM INTO SHORTER STANDARD LENGTHS. COSTS ARE DEFINED IN TERMS OF THAT ARISING FROM THE ENTRY OF A SINGLE ADDITIONAL VEHICLE; THIS VEHICLE DOES NOT AFFECT THE FLOW RATE OF THOSE IN FRONT BUT ALTERS THE DENSITY, FLOW RATE AND TRAVEL TIME FOR ALL TRAFFIC FOLLOWING. THE MANNER IN WHICH COSTS VARY FROM SEGMENT TO SEGMENT AS THE VEHICLE MOVES ALONG THE ROAD MUST THEN BE DETERMINED. THE SOLUTION TO THIS PROBLEM IS EMPIRICAL, BUT THE AUTHORS SUGGEST A METHOD THAT COULD BE USED BY TAKING THE OUTFLOW PATTERN FROM THE FIRST SEGMENT TO BE THE INFLOW INTO THE NEXT SEGMENT - AND SO ON. IT IS EXPECTED THAT, FOR EACH SUCCESSIVE SECTION, THE OUTPUT PROFILE OF RATE AGAINST TIME WOULD BE FLATTER AND HAVE A LONGER 'TAIL' THAN THE PRECEDING SEGMENT. TRAFFIC DENSITY WILL RISE IN THE FIRST SEGMENTS UNTIL THE INFLOW STARTS TO FALL WHEN IT REACHES A MAXIMUM AND FALLS THEREAFTER. THESE SUGGESTIONS RETAIN THE GENERAL NATURE OF THE ORIGINAL PAPER.
Abstract