One of the most momentous but least well-known challenges facing U.S. cities in the age of COVID-19 is that public transit may be on the verge of collapse. Many of the nation’s transit agencies are in an existential crisis. Transit fares and the local taxes that fund this essential service have fallen by up to 90 percent in major cities.

In addition, thousands of transit workers have fallen ill with the coronavirus as they keep cities moving and bring essential workers to their jobs. Cities cannot survive without transit, yet transit cannot survive without a significant federal cash infusion.

The American Public Transportation Association is urging Congress to include $32 billion for transit relief in its second coronavirus relief bill. The Senate version failed to do so.

Transit agencies throughout the country have acted swiftly and smartly to respond to the pandemic, by adding service to hospitals and grocery stores. Agencies made their own hand sanitizer, retrofitted buses to protect drivers, scrubbed every inch of their vehicles and, most importantly, kept running as much as possible.

But transit systems are being forced to make painful decisions. For example, San Francisco has warned that up to 40 of its 68 bus lines could be permanently axed. Denver’s Regional Transportation District has already reduced service by 40 percent and has warned that more cuts may be necessary. These cuts will devastate people who are already struggling to make ends meet, and an economy that is already in dire straits.

Millions of people, including 2.8 million essential workers, rely on transit every day. With service cuts, buses will become slower and overcrowded. People will spend more hours on them, with less space to socially distance on board. This will increase dangers for an already at-risk population.

Funding transit is not just about the riders, it’s about the future of our country’s economy. Transit connects people to employment. It enables cities to avoid paralyzing gridlock. It employs hundreds of thousands and supports even more jobs.

According to the advocacy group Transportation for America, “more than two thousand manufacturing facilities and companies, spread across 49 states, are tied directly to the manufacture or supply of new transit systems and repairs and upgrades to existing systems.”

In March, Congress passed the CARES Act, which included $25 billion for transit agencies.

Airlines, which move only half as many people nationally as ride the bus and subway in New York City each day, received $50 billion from CARES.

Further, the most-used transit systems received only enough support to keep operating for a limited time. For example, NYC’s transit system, which serves 38 percent of all transit riders in the U.S., received 15 percent of the funding, just enough to stay solvent through the summer.

It’s not just New York. Many more cities — Boston, Chicago, D.C., Los Angeles, Philadelphia, San Francisco, Seattle — barely have enough to make it to the end of the year. Transit urgently needs more funding to keep the wheels rolling, with much of it going to larger systems.

Congress must act quickly to address this pressing need. Our cities, our essential workers and our economy all rely on it.

Corinne Kisner is executive director of the National Association of City Transportation Officials.