Modification of Saturation Flow Formula by Width of Road Approach

Saturation flow formula, S=600We is common used in Indonesia for any width of road approach at signalized intersections. In supporting the truth of the formula, it was held the observation at several signalized intersections in Bandung city. The signalized intersections have the width of road approaches in varies from 3 up to 12 meters. The observations had been done in morning, noon, and afternoon peak times to get the values of observed saturations flows for each road approach. Then the field results are compared with the values of formula calculations. When the rank width of road approaches is small (3, 4, 5.9 m) up to medium (6, 7, 8.9 m) the values of saturation flows are closed each other. When the rank width of road approaches become large (9, 10, 11, 12 m) there are significant different between observed and calculated values of saturation flows. By using computerized program the closed formula with observed values is S=500We+400 for large width of road approach. © 2011 Published by Elsevier Ltd.