Vehicle delay at signalized intersections as a factor in determining urban priorities

ONE OF THE PERTINENT FACTORS IN RATING URBAN SECTIONS ON THE STATE HIGHWAY SYSTEMS IN THE TENNESSEE PLANNED CONSTRUCTION PROGRAM PROCEDURE IS VEHICLE DELAY OCCASIONED BY TRAFFIC SIGNALS. THE OBJECTIVE IS TO COMPARE ONE URBAN SECTION WITH ANOTHER AS TO THE AVERAGE TOTAL DELAY OCCASIONED BY THE SIGNALS IN 24 HOURS. BASED ON DATA CONTAINED IN THE 'HIGHWAY CAPACITY MANUAL', TOGETHER WITH SOME REASONABLE ASSUMPTIONS, AVERAGE SECONDS OF DELAYS PER VEHICLE WERE COMPUTED FOR AN INTERSECTION OPERATING AT POSSIBLE CAPACITY (BY DEFINITION) AND VARIOUS PERCENTAGES OF OPERATION ABOVE AND BELOW THIS CAPACITY. A PERCENTAGE DISTRIBUTION OF VEHICLES DELAYED LESS THAN ONE CYCLE, AND THOSE DELAYED ONE, TWO, THREE, ETC., FULL CYCLES WAS DETERMINED FOR EACH CONDITION OF OPERATION. THE AVERAGE DAILY TRAFFIC IS RELATED TO THE GEOMETRICS OF THE SIGNALIZED INTERSECTION UNDER STUDY TO DETERMINE THE PERCENTAGE OF PRACTICAL CAPACITY. ONCE THIS DETERMINATION HAS BEEN MADE, THE AVERAGE DELAY FOR VEHICLES FOR THE HIGHEST HOUR AND EACH SUCCESSIVE HOUR IN THE DAY CAN BE DETERMINED. THE TOTAL DELAYS FOR ALL SIGNALIZED INTERSECTIONS WITHIN THE SECTION UNDER STUDY ARE THEN TOTALED. THE AVERAGE DELAY PER MILE FOR ONE ROUTE SECTION CAN THEN BE COMPARED WITH ANOTHER FOR THIS PARTICULAR FACTOR IN THE TOTAL PROGRAM STUDY. /AUTHOR/