Round About Design at Salh Intersection – A case study

Roundabout is a specialized form of at grade intersection which allows the movement of traffic in one direction around the central island and move out of the roundabout into their desired direction. In this research work, traffic volume count study, spot speed study, level of service are determined and design of roundabout at Salh intersection Ludhiana, Punjab as per IRC:65-2017 is done. Traffic volume count study found out that traffic volume at the site is 3362 PCU/hr, thus roundabout is required at the site. From spot speed study, mean speed obtained at BRS bypass road, Phullanwala chowk road, City centre road and Ramgarhia road are 31.6, 28.4, 30.96 and 34.11 kmph respectively. Thus, design speed for the roundabout is taken as 30 Kmph. Level of service at the site is calculated by vehicular delay model as per IRC: 65-2017. Vehicular delay is 29.96 seconds, thus level of service at the site is D. Level of service D indicates unstable flow, with tolerable operating speeds being maintained though considerably affected by changes in operating conditions. Fluctuations in volume and temporary restrictions to flow may cause substantial drop in operation speeds.