Testing the proportionality condition with taxi trajectory data

- Validate the behavioural realism of the proportionality condition using taxi's route choice patterns.
- Develop a method to uncover a set of valid paired alternative segments (PAS) from a large amount of taxi trajectory data.
- Test the proportionality condition by performing linear regression analysis and chi-square tests on the valid PASs.
- Show that the majority of the PASs tested (up to 85%) satisfy the proportionality condition at a reasonable level of statistical significance.

The proportionality condition has been widely used to produce a unique path flow solution in the user equilibrium traffic assignment problem. However, it remains an open question whether and to what extent this condition accords to real travel behavior. This paper attempts to validate the behavioural realism of the proportionality condition using more than 27 million route choice observations obtained by mining a large taxi trajectory data set. A method is first developed to uncover more than three hundred valid paired alternative segments (PAS), on which the proportionality condition is tested by performing linear regression analysis and chi-square tests. The results show that the majority of the PASs tested (up to 85%) satisfy the proportionality condition at a reasonable level of statistical significance.