Implementation of alternative intersections in South Africa : operational conundrum or cost effective infrastructure solution

Abstract

The existing Diamond Interchange at the crossing of the N1 with Sefako Makghato Drive (Route K14) in the City of Tshwane Metropolitan Municipality was recently, in 2015, upgraded to a Diverging Diamond Interchange (DDI). The Diverging Diamond Interchange is one of the so-called alternative intersections based on innovative approaches to avoid or minimise opposing traffic flows. The paper presents the results of capacity and operational analyses by means of analytical techniques (SIDRA 7.0 Plus), and also evaluates the cost-effectiveness. Typical operational challenges of the urban environment, i.e. non-motorised transport, disorderly taxi behaviour, power outages, etc. were also addressed.