Jun 10, 2021 5:54 PM EDT Millions of commuters in the U.S. continue to rely on public transit, even as the COVID-19 pandemic has forced riders to contend with social distancing and other safety measures. To adapt to the spread of the airborne virus and to anticipate a post-pandemic world in which people are still wary of close contact, transportation agencies in major cities have had to quickly change the way they plan and conduct their services. The most obvious change the agencies have adapted is the amount of thorough cleaning required to keep passengers safe and encouraging six feet between passengers.