Designing Criteria of Acute Angle Four-Leg Intersection At-Grade

In designing practice, supported by adequate guidelines for designing, the standard approach to designing intersection which axes intersect at acute angle (< 70°), in the first instance comes down to the reconstruction of the minor road axis aimed at making favourable angle (≈ 90°) of the axis in the intersection area. That requires the realignment of minor road route at longer line, with negative consequences of building costs and land purchase. The paper presents a part of more extensive research referring to finding possibilities of designing such intersections without the reconstruction of the minor road axis, respecting vehicle movement geometry patterns. In doing so, the usual designing order was changed by which intersection elements and intersection itself are shaped first and then swept path width for relevant design vehicles is checked. Vehicle movement simulations were carried out by computer programmes, which reliability was proved by comparing results with those of actual vehicles on test field. The paper on representative examples illustrates solutions and necessary modifications of the conventional way of designing intersection elements referring to four-leg intersections with acute intersecting angle. They do not disrupt the principles of designing practice: safety and unobstructed traffic flow.