Methodological Issues in Developing Mode Choice Models for Dhaka, Bangladesh

This paper presents issues and challenges associated with development of a comprehensive mode choice model for Dhaka, the capital of Bangladesh and the 11th largest city in the world. As in most other developing countries, reliable level-of-service data are not available for the wide variety of motorized and nonmotorized modes used by travelers in Bangladesh. In addition, the 12 million inhabitants of Dhaka have wide differences in affordability of and accessibility to various modes. These differences result in substantial heterogeneity in inhabitants' choice sets. These choice sets are also unobserved in the data and not easily inferable from the limited information of the network. This paper identifies key limitations of the available data and proposes methods to overcome those limitations. A probabilistic choice set of modes from a small-scale stated preference survey has been used to account for the absence of actual choice set data. The systematic and stochastic errors in the network-derived time data are explicitly accounted for in the model structure. The improvements from the proposed approaches are demonstrated by prediction tests using holdout samples. The proposed approaches have immense potential to improve travel mode choice models for other cities of Bangladesh, as well as cities in other developing countries, which very often face similar data issues.