Upgrading of a Two Way Stop Controlled Intersection into a Restricted Crossing U-Turn Intersection.

Abstract

Traffic delay problems are increasingly manifesting on urban roads in the world’s cities, affecting economies and livelihoods. These are caused by both growth of number vehicles on the roads and inadequate road capacity. Traffic delays are very significant on road intersections due to the need to create right of way for all possible movements. TWSC intersections pose a big delay threat to the less priority minor street traffic. A number of approaches have been taken to address the challenge of traffic delays. Conventionally, signalization and use of roundabouts are done. Recently, non-conventional intersections have been invented to improve the conventional approaches. Popular of these non-conventional intersections is the Restricted Crossing U-Turn intersection (RCUT). RCUT eliminates the minor road through and right turn movements at the intersection. The drivers are compelled to turn left and complete the required movements by making U-turn at a one-way median opening at least 400 feet (120m) after the intersection. This study seeks to examine the performance of the Restricted Crossing UTurn (RCUT) intersection as one of the possible remedies. A case study of a two way stop controlled junction (Mambule junction in central Uganda) was used. This study intended to assess the current performance of this junction. The junction was converted to a hypothetic signalized four-legged and RCUT intersections. The current performance of the intersection was compared to the performance in the hypothetic forms. From the study carried out at Mambule Junction, it was observed that conversion from the existing TWSC to RCUT and conventional signalization would reduce the control delay to minor street approaches from over 1500s to 16.33s and 32s respectively. This delay reduction is accompanied with an increase in capacity from the existing 100 veh/hr to 849 veh/hr and 500 veh/hr in RCUT and conventional signalization respectively. It can be noted that RCUT almost doubles the performance of conventionally signalized intersection.