BOSTON (AP) — Public transit systems typically marked by jammed buses and subway trains are now grappling with the exact opposite: disappearing riders.

Some systems are reporting subway ridership of less than 10% of usual demand as fears of the coronavirus and stay-at-home orders have riders abandoning time-worn methods of navigating cities.

While agencies say public transit is still critical to help doctors, nurses and medical workers get to their jobs, no one is exactly sure when riders will begin returning in larger numbers — and how.

A $25 billion federal aid package is helping some systems maintain service in the meantime.