Modelling of traffic operations in urban networks of developing countries: a computer aided simulation approach

Abstract

In developing countries, significant proportions of both motorised and non-motorised vehicles with considerable variations in speed, size and manoeuvrability share the same road space. Also, drivers do not usually follow lane discipline and can occupy any lateral position on the road. The substantial differences in the traffic and roadway characteristics between developing and developed countries means that the traffic engineering practices, mostly based on the developed country research, are unlikely to give reliable results if applied in countries such as Bangladesh. Therefore, a new research tool is necessary which can be used for comprehensive understanding of the developing countries traffic operation at network/corridor level. A computer aided micro-simulation model is developed which would be able to simulate the traffic operations in urban networks/corridors of developing countries. In order to be able to replicate the non-lane based flow characteristics of developing countries traffic, a co-ordinate approach to modelling vehicle location is adopted. An extensive video and manual data collection exercise is made in Dhaka, Bangladesh for the purpose of calibration and validation of the model. While the model is validated with real field data using different statistical tests the dynamic graphical output and display of the simulated traffic flow has been very useful in the calibration and verification process. The model is applied to various roadway and traffic conditions. In general, it is found that the operating speed of motorised vehicles decreases because of mixing with the non-motorised vehicles. With a right turning restriction on non-motorised vehicles, the same increases significantly. Also, the operating speed of motorised vehicles is more sensitive to the changing situation than that of the non-motorised vehicles. For higher demand flow, lower road width and higher proportion of non-motorised vehicles, the larger size vehicles experience the higher delay.