It would be helpful if transit riders wore PPE that would prevent them from spreading anything they may have. It is going to be critical to make basic masks available to the whole population. Buses can have more hand sanitizers or cleaning wipes available for the driver and riders. Drivers can have a clear plastic door separating them from the rest of the bus and passengers who are entering buses. Surfaces in buses can be made of materials that are easier to clean and disinfect, so many cloth seats will have to be replaced. It also can be helpful to get more ventilation in the buses and trains. If it is possible, cities can run more buses and trains so then they will not be a full, especially during peak travel hours and on popular routes. I know most transit systems do not make up their operating costs, so it may not be feasible to add more vehicles/cars to the operating system, but it would make overcrowding in public transit less of a concern.