Effectiveness of integrated traffic management for a combined flyover system in Colombo: a microsimulation approach

Major arterial roads in city centres often face ever-increasing traffic demand periodically addressed through developments to ease congestion on road links and improve integrated road connectivity. Towards this end, three flyovers are proposed in the Slave Island area in Colombo. This high-investment project of the Sri Lankan Government expects the flyovers to prevent peak-hour traffic delays from the frequent road closures at two railway gates while providing for the higher traffic generated from the land use changes in the area. The project also expects to relieve congestion in the adjacent road network. This research investigates the outcomes expected of integrated traffic management from the project. A traffic analysis was carried out for the entire road network of the project impact area using the PTV Vissim software. Moreover, current and future land use was considered in assessing network connectivity over the design life. Alternative traffic management options were tested to identify the most feasible arrangement for connecting the proposed flyovers. Origin-Destination data from 2018 were used to determine intersection capacities and pedestrian movements. Results reveal that delays due to railway gate closure reduced, though a significant traffic diversion from the proposed flyover network was not evident.