Crowding in public transport: A review of objective and subjective measures

Abstract

In order to capture the user benefits associated with reduced crowding from improved public transport (converted to dollars via willingness to pay estimates), it is necessary to identify the relevant dimensions of crowding that are meaningful measures of what crowding means to travellers. There are a number of objective and subjective measures of crowding promoted in the literature, with some objective measures (e.g., passenger density) being used as the basis of a standard of acceptable levels of practice in specific public transport systems. Violation of the standard is typically used to establish unacceptable levels of crowding. A major limitation of existing crowding measures, especially when a user-related measure of willingness to pay to reduce levels of crowding is important in economic appraisal, is the absence of measures that represent the subjective perception of crowding. There is a disconnection between objective measures and subjective measures, the latter representing what matters to users. We reveal the significant gap between objective and subjective measures of crowding. The paper promotes the case for efforts to quantify user perceptions of crowding in a way that enables a link to behaviourally meaningful estimates of willingness to pay to reduce crowding, so that the changes in crowding linked to objective measures (e.g., passenger density), can be translated into appropriate subjective levels of crowding reduction benefit.