The Gini index of demand imbalances in public transport
Document Type
Journal Article
Publication Date
2021
Subject Area
ridership - demand, ridership - elasticity, economics - operating costs, economics - pricing, economics - subsidy, policy - fares, operations - capacity, operations - frequency, planning - methods
Keywords
Public transport, Demand imbalances, Gini coefficient, Optimal pricing, Subsidies
Abstract
The paper studies a general bidirectional public transport line along which demand varies by line section. The length of line sections also varies, and therefore their contribution to aggregate (line-level) user and operational costs might be different, even if demand levels were uniform. The paper proposes the Gini index as a measure of demand imbalances in public transport. We run a series of numerical simulations with randomised demand patterns, and derive the socially optimal fare, frequency and vehicle size variables in each case. We show that the Gini coefficient is a surprisingly good predictor of all three attributes of optimal supply. These results remain robust with inelastic as well as elastic demand, at various levels of aggregate demand intensity. In addition, we find that lines facing severe demand imbalances generate higher operational cost and require more public subsidies under socially optimal supply, controlling for the scale of operations. The results shed light on the bias introduced by the assumption of homogeneous demand in several existing public transport models.
Rights
Permission to publish the abstract has been given by SpringerLink, copyright remains with them.
Recommended Citation
Hörcher, D., & Graham, D.J. (2021). The Gini index of demand imbalances in public transport. Transportation, Vol. 48, pp. 2521–2544.
