SHOULDER USE ON AN URBAN FREEWAY

THE EXTENT OF A SHOULDER USAGE ON AN URBAN FREEWAY AND THE TYPICAL CHARACTERISTICS OF THIS USAGE WERE STUDIED BY DETERMINATION OF' /1/ THE AMOUNT OF SHOULDER USAGE ON SOME RATE BASIS, /2/ USE BY TYPE OF VEHICLE, /3/ LENGTH OF STAY, /4/ REASON FOR USING THE SHOULDER, /5/ ASSISTANCE RECIEVED, /6/ OTHER VEHICLES INVOLVED IN THE SAME INCIDENT, AND /7/ THE FINDINGS IN RELATION TO OTHER SHOULDER USAGE STUDIES. THE STUDY WAS CONDUCTED ON THE JOHN C. LODGE FREEWAY IN MIDTOWN DETROIT. IT IS A DEPRESSED FACILITY WITH FULL CONTROL OF ACCESS. SHOULDER USAGE WAS STUDIED BY CONTINUOUS OBSERVATION OF TRAINED OBSERVERS USING 14 CLOSED-CIRCUIT TELEVISION CAMERAS SPACED FROM 800 TO 1800 FEET APART ON THE FREEWAY. TRAFFIC VOLUME INFORMATION WAS OBTAINED BY ULTRASONIC DETECTING EQUIPMENT LOCATED OVER EACH LANE OF THE FREEWAY AT TWO LOCATIONS. THE FINDINGS SHOW THAT' THERE WAS AN INCIDENT INVOLVING ONE OR MORE VEHICLES USING THE SHOULDER FOR EVERY 5,300 VEHICLE MILES OF TRAVEL DURING THE OVERALL STUDY PERIOD, SHOULDER USAGES FOR REASONS NOT EVIDENT TO THE TELEVISON OBSERVER CONSTITUTED THE GREATEST NUMBER OF CASES, AND THE MOST FREQUENT SINGLE REASON FOR STOPPING THAT COULD BE DETERMINED WAS BECAUSE OF, OR TO ASSIST, ANOTHER SHOULDER USER, AND MOTOR AND TIRE TROUBLE WERE THE NEXT MOST FREQUENT VISIBLE REASONS.