Traffic congestion in Colombo, the capital city of Sri Lanka, has been a persistently aggravating issue since 1978, given the increased rate of private vehicle ownership resulting from the introduction of open economic policies. The city‟s travel demand is enormous: many junctions get congested with static traffic flow especially during peak hours. This has posed a huge financial and economic loss to the country. Industrial development and expansion of businesses seem to have contributed, to a great extent, to congestion, further supported by the growing affordability of private vehicle use due to reduced import taxes, increased per capita incomes, affordable fuel prices, lack of road pricing schemes etc. Several other factors that would potentially further aggravate the present traffic congestion in the road links of urban and suburban centres can be identified. Among those figure inadequacy of road capacity to cater to increased traffic levels, delays at intersections owing to bottlenecks at intersection approaches, signal delays at main intersections, excessive weaving actions at un-signalised intersections, increased tendency for violation of traffic rules and absence of driver discipline. Therefore, the mitigation of traffic congestion using integrated engineering solutions (IES), an inter-disciplinary approach combining conventional engineering with humanities, becomes very important in view of optimising the capacity of the already improved road networks in urban areas. These IESs are more appropriate over conventional traffic mitigation methods for their ability to provide proper information to road users in timely manner, and also for their lesser requirement of human involvement, properties and assets to cater for growing demand for capacity, land acquisition which is a deciding factor of great concern, especially in urban city centres.

Perera, K.R., Liyanage, T.U., & Senevirathne, S. (2016). Introduction of an integrated engineering solutions to ease the rapidly increasing traffic condition in main city centres: a case study of traffic simulation at main network with proposed Rajagiriya flyover [Extended Abstract]. In T.L. Gunaruwan (Ed.), Proceedings of 1st International Conference on Research for Transport and Logistics Industry 2016 (pp. 37-40). Sri Lanka Society of Transport and Logistics. https://slstl.lk/r4tli-2016/