Nanyang Technological University commissioned CPG Consultants to undertake a capacity analysis, accident analysis and road safety review for the junction of Nanyang Avenue and Nanyang Drive. The capacity analysis for existing traffic volumes showed that the junction operated satisfactorily except for the Nanyang Drive westbound approach, where all movements are Level of Service (LOS) F, and the Nanyang Drive eastbound approach, where the through and right turn movements are LOS D.
Analysis of the accident patterns showed that 11 of the accidents involved vehicles travelling eastbound on Nanyang Drive failing to give way, which resulted in collisions with vehicles travelling southbound on Nanyang Avenue. Three of these accidents involved minor injuries. However, as these are right angle collisions, they had the potential to be more serious. Provision of a roundabout at the junction would be an effective means of addressing this type of accidents.
The final roundabout option selected incorporates additional approach lanes on the Nanyang Avenue southbound and Nanyang Drive eastbound legs, and has two circulating lanes. The roundabout operated well with existing traffic volumes and the sensitivity analysis showed that it would continue to operate satisfactorily even with 30% growth in traffic. It did not involve major civil works as it was constructed within existing kerb lines.