THE PHOTOGRAPHIC METHOD OF STUDYING TRAFFIC BEHAVIOR

Abstract

A NEW METHOD IS PRESENTED FOR SECURING ACCURATE DATA ON TRAFFIC BEHAVIOR BY MEANS OF PICTURES; THE USE OF SUCH DATA IS ILLUSTRATED IN THE RELATION BETWEEN THE NUMBER OF VEHICLES PASSING A GIVEN POINT, THEIR AVERAGE SPEED, AND SPACING. FROM THE POSITION OF A VEHICLE IN TWO OR MORE PICTURES TANEN AT SHORT DEFINITE INTERVALS OF TIME ITS VELOCITY AND ACCELERATION CAN BE DETERMINED. A SIXTEEN MINUTE SIMPLEX MOVING PICTURE CAMERA WAS GEARED FOR A CONSTANT TIME INTERVAL BETWEEN EXPOSURES. FROM 6,000 PICTURES OF 794 VEHICLES THE FOLLOWING EXPRESSION FOR THE SPACING OF CARS WHOSE SPEEDIS CONTROLLED BY THAT OF THE LEADING CAR OF A GROUP WAS DEVELOPED: S = 21 + 1.1 V WHEREIN S IS THE DISTANCE CENTER TO CENTER IN FEET BETWEEN THE VEHICLES AND V IS THE VELOCITY IN MILES PER HOUR. /AUTHOR/