Modelling the impacts of reducing non-motorised traffic in urban corridors of developing cities

In many cities in developing countries, both motorised and non-motorised vehicles share the same carriageway. Drivers of motorised vehicles can experience high levels of conflict with non-motorised vehicles because of the lack of lane discipline in such mixed traffic situations. As a result, the motorised vehicles have low operating speeds, particularly adjacent to intersections. This paper assesses the potential impact of reducing the proportion of non-motorised vehicles and of banning them. Available traffic models and empirical relationships were not found to be suitable for studying the mixed traffic operation and were mostly based on lane-based motorised traffic. Therefore, a micro-simulation model was developed for this study. The model was calibrated and validated using extensive traffic data from Dhaka, Bangladesh. It was applied to see the effect of varying the proportion of non-motorised vehicles on the performance of a corridor of Dhaka city. The study revealed that even a low proportion of non-motorised vehicles (i.e. 10% of the traffic mix) reduces the operating speed of motorised vehicles significantly. Any increase in the proportion of non-motorised vehicles beyond 30% has little effect on the mixed traffic performance. However, the banning of non-motorised vehicles resulted in a 30% reduction in corridor travel time for motorised vehicles. Banning could also result in an increase in corridor passenger movement capacity of more than 300% without increase in journey time.