A study of four-way stop intersection capacities

CAPACITIES WERE STUDIED OF FOUR-WAY STOP-CONTROLLED INTER- SECTIONS VARIOUS TRAFFIC AND OPERATING CONDITIONS. THREE RIGHT ANGLE INTERSECTIONS IN THE CHICAGO METROPLITAN AREA WERE OBSERVED AND ANALYZED. A TRIAL CAPACITY CHART FOR FOUR- WAY STOP INTERSECTIONS IS PRESENTED WHICH SUMMARIZES THE MOST IMPORTANT RESULTS OF THE STUDY. CAPACITIES WERE DERIVED FROM THE AVERAGE DEPARTURE HEADWAY OF VEHICLES AS THEY ENTERED THE INTERSECTION AREA. THE FOLLOWING VARIABLES WERE INVESTIGATED AS TO THEIR EFFECT ON THE CAPACITY' 1/ TWO SPLITS IN VOLUME FOR ONE-LANE APPROACHES DURING PRESSURIZED CONDITIONS, WITH A CONTINUOUS BACKLOG OF WAITING VEHICLES, 2/ FOUR-LANE AND TWO-LANE TWO-WAY CROSS-STREETS FOR SIMILAR TRAFFIC CONDITIONS, 3/ VARIATIONS IN LEFT AND RIGHT TURNS AND PERCENT OF COMMERCIAL VEHICLES 4/ WAITING VEHICLES ON THE CROSS-STREET, VS NO VEHICLES ON THE CROSS-STREET, VS VEHICLES FROM CROSS-STREET ENTERING THE INTERSECTION IN TURNS WITH THE APPROACH VEHICLES UNDER STUDY THE RESULTS OF THIS STUDY ARE BASED ON RELATIVELY LIMITED DATA, THEREFORE, IT IS POSSIBLE THAT CERTAIN UNKNOWN LOCATION FACTORS MAY HAVE BIASED THE SAMPLES.