Three-leg Intersection at-Grade – The Right Edge Forming Test

There are no regulations or standards in the Republic of Croatia concerning the formation of at-grade intersection elements. For this reason, German standards are used in designing such intersections. Frequently, right edge damage can be observed on at-grade intersections. This study was conducted as a part of ongoing scientific research aimed at reducing this phenomenon. A numerical model developed by the Faculty of Civil Engineering (University in Zagreb) was used to test vehicle movement. Reliability was checked on the basis of results of drives on the test field. This paper deals with tests carried out on two basic types of 3-leg at-grade intersections as defined by German regulations regarding intersection design outside urban areas. The testing of the formation of the intersection right edge line was carried out by observing the intersection as a whole, so that the test drives were first performed in all possible directions of movement by relevant vehicles through the intersection, at different selection of steering paths and crossing angles of the road axes of the main and secondary directions less than or equal to 90o. The results of the test drive presentations show that right edge formation in compliance with the German regulations by means of three circular arcs with radii ratio 2:1:3 does not ensure an undisturbed drive for the tested vehicles. Taking the results of the test drive into account, a proposal for formation of the intersection right edge is given.