Clearance speed study for intergreen time determination

Abstract

Intergreen is the period between ends of a green period of one phase and the beginning of a green period of the next phase at signalized intersections. Its determination requires data which are in relation of geometrical parameters of junctions and that of dynamic parameters of the entering in and passing through the crossroads vehicles. One of them is clearance speed of a last passing vehicle of a phase which is necessary to calculate its clearance time. The present study aims to determine values of clearance speed for straight ahead and turning vehicles and find a relations between them and curves radii, slope of the road etc. The study use field data bring at three traffic lights junctions in Sofia city. The obtained results and the conclusions reached would be used in intergreen time determination for phasing design optimization at these junction and the other one in the same condition includes clearance distance and curves radii of turning flows.