ACCIDENTS, SPEED DEVIATION AND SPEED LIMITS

THIS RESEARCH SOUGHT TO IDENTIFY CHARACTERISTICS OF ACCIDENT-INVOLVED VEHICLES PRIOR TO THEIR ACCIDENT. SPEED DEVIATION, AS ESTIMATED BY AN ACCIDENT INVESTIGATION TEAM, WAS CORRELATED WITH TRAFFIC SPEED PRIOR TO THE ACCIDENT, AS MEASURED BY A COMPUTER. THE COMPUTER OUTPUT PROVIDED AN OVERVIEW OF THE TRAFFIC FLOW AT EACH OF 16 MAGNETIC LOOP SENSORS AT REGULAR INTERVALS ON INDIANA STATE HIGHWAY 37 NEAR BLOOMINGTON. INVOLVEMENT RATE PER MILLION VEHICLE-MILES WAS FOUND TO BE HIGHER FOR THE SLOW DEVIATION VEHICLES THAN FOR THE FAST DEVIATION VEHICLES. HIGHER ACCIDENT RATES WERE ASSOCIATED WITH INTERSECTIONS. THE INVOLVEMENT RATE WAS FOUND TO BE APPROXIMATELY THE SAME FOR HIGH AND LOW SPEED DEVIATIONS AFTER DELETION OF ACCIDENTS INVOLVING TURNING VEHICLES. SPEED LIMITS SET AT THE 85TH AND 15TH PERCENTILE SPEED, AND ENFORCEMENT AT THE 95TH AND 5TH PERCENTILE WERE RECOMMENDED.