Corridor Level Traffic Management Through Variable Messaging Systems: A Case Study on East-West Links Entering Colombo

The use of variable message signs (VMS) is an effective method for providing drivers with real-time traffic information. Drivers being aware of the real-time traffic condition of the system, allow drivers to explore different route options and balances the road network to reach equilibrium in a very short time. In the context of developing countries where the majority of drivers don't use vehicle in-built navigational systems or smart devices with navigational applications, the use of VMS is more important. This study develops a methodology to identify the optimal locations to establish a Variable Message Sign system for corridor level traffic balancing and management for any number of pre-identified interventions. The study compares the multi-user class trip assignment result from a calibrated, study area-wide, macroscopic trip assignment model for a typical road network and the same road network with the interventions. It identifies the locations to place VMS to divert traffic to have both user and system optimization. The validity of the strategy was tested through a case study of traffic entering and leaving the Colombo, Sri Lanka from East-West corridor. 6 major locations for corridor level diversion using VMS and 7 minor locations to support the major diversion using auxiliary signage boards were identified. The results show that with 30% of potential diversion vehicles directed through VMS, a 10% vehicle reduction in the Rajagiriya section and 18% in Malabe could be achieved.