Chicago Transit Authority, in conjunction with the Chicago Department of Public Health, CTA coronavirus operating rules: passenger capacity limits, rear-door boarding, mask requirement (agency page as archived June 2, 2020) (Ex. MET-CHI-050)
Commuter Rail Division of the Regional Transportation Authority (Metra), Metra COVID-19 operating rules: mask mandate and alternate schedules (agency page as archived Aug. 2, 2021) (Ex. MET-CHI-051)
Chicago Department of Public Health (official COVID-19 Orders web page), CDPH 'COVID-19 Orders' page as archived October 17, 2021 (Current Orders list and order summaries) (Oct. 17, 2021) (Ex. MET-CHI-061)
