ACCIDENTS ON MOTORWAYS. RELATION BETWEEN PERSONAL INJURY ACCIDENTS AND VARIOUS STRUCTURAL AND TRAFFIC FACTORS

DATA OBTAINED FROM NEARLY ALL THE MOTORWAY SECTIONS IN OPERATION AT THE BEGINNING OF 1968, 1970 AND 1973 ON ROADWORKS, NUMBER OF LANES, UPHILL OR DOWNHILL GRADIENTS, AVERAGE DAILY TRAFFIC, THE PROPORTION OF GOODS TRAFFIC AND HEAVY GOODS TRAFFIC AND OVERALL ACCIDENT RATES SERVED AS A BASIS FOR STUDIES OF THE EFFECT OF TRAFFIC AND STRUCTURAL FEATURES ON ACCIDENTS ON FEDERAL MOTORWAYS, THE RESULTS OF WHICH ARE REPORTED HERE. IT WAS SHOWN THAT, DURING THE YEARS WHEN OBSERVATIONS WERE CARRIED OUT, TOTAL NUMBERS OF ACCIDENTS INVOLVING PERSONAL INJURY DECREASED, ACCIDENT RATES ON MOTORWAYS HAVING A HARD SHOULDER BEING LOWER THAN ON THOSE WITHOUT A HARD SHOULDER. COMPARED WITH 1968, IN THE TWO OTHER YEARS WHICH HAD INCREASED DAILY TRAFFIC THERE WAS AN INCREASE IN ACCIDENT RATES. OVERALL THERE WAS A REDUCTION IN THE RATES OF PERSONAL INJURY ACCIDENTS; THIS WAS ALSO NEARLY ALWAYS THE CASE WHEN THE INFLUENCING FACTORS WERE CONSIDERED SEPARATELY.