COMPARISON OF TWO TECHNIQUES OF AERIAL PHOTOGRAPHY FOR APPLICATION IN FREEWAY TRAFFIC OPERATIONS STUDIES

AERIAL PHOTOGRAPHY WAS ANALYZED ON THE GULF FREEWAY IN HOUSTON, TEXAS, TO DESCRIBE TRAFFIC OPERATION OVER LONG SECTIONS OF THE FREEWAY AS AN ALTERNATIVE TO TELEVISION MONITORING SYSTEMS. THE METHODS OF AERIAL STRIP PHOTOGRAPHY OF TWO CONTINUOUS STEREOSCOPIC PHOTGRAPHS TAKEN SIMUL- TANEOUSLY FOR THE TRAFFIC SURVEY SECTION, AND OF AERIAL TIME LAPSE PHOTOGRAPHY WERE COMPARED. DATA MEASUREMENT AND REDUCTION FROM AERIAL PHOTOGRAPHS IS STILL A TIME-CONSUMING TASK. TRAFFIC SURVEYS BY AERIAL PHOTOGRAPHIC TECHNIQUES ARE LIMITED TO THE HOURS OF GOOD LIGHTING AND FLYING CONDITIONS. THIS PREVENTS GETTING AERIAL PHOTOGRAPHY DURING HOURS OF PEAK TRAFFIC DURING WINTER MONTHS UNDER THE WORST DRIVING CONDITIONS. CONTINUOUS-STRIP FILM PHOTOGRAPHY PROVIDED MORE COVERAGE FOR THE MONEY EXPENDED THAN TIME-LAPSE PHOTOGRAPHY. MORE SPEED READINGS WERE OBTAINED BY USE OF THE TIME-LAPSE PHOTOGRAPHY.