Miller, Caroline & Ian Savage (2017). Does the demand response to transit fare increases vary by income? Transport Policy 55:79-86.
[Journal Website]  [Manuscript Version]

Changes in ridership at individual stations on Chicago's mass-transit rail system following fare increases in 2004, 2006, 2009 and 2013 are analyzed to determine whether the ridership response varies with the per capita income in the neighborhood surrounding each station. We find mixed results. For one of the four fare changes the decline in ridership is greater in lower-income neighborhoods than it is in higher-income neighborhoods. However, the reverse is found for another fare increase. For two of the increases there is no relationship between income and ridership response. These mixed findings are in line with the prior literature that also found an inconsistent relationship. We hypothesize that there are two competing forces at work. On one hand lower-income groups are more constrained in their budget, but on the other hand they have fewer options for switching to other modes.