By: Richard A. White; Acting President & CEO of the American Public Transportation Association

This piece originally appeared in Newsweek.

Decades of wear, tear and insufficient investment are catching up with our nation’s public transportation systems.

Due to a lack of funding, New York transit officials have announced plans to shut down the “L” train—which links Chelsea in Manhattan to Canarsie in Brooklyn—for 18 months. In Washington, D.C., Metrorail officials are in the midst of a long-term project to rebuild the region’s subway system.

Simply put, America’s transportation infrastructure is falling apart, thanks to inadequate investment. It’s high time our leaders—from all levels of government—made rebuilding that infrastructure a priority. Doing so would create jobs, boost the economy, improve mobility and strengthen our communities.

Transportation leaders are reckoning with years, even decades, of deferred maintenance. In 2013, the Chicago Transit Authority conducted critical renovations that necessitated a five-month closure of its most popular train line. It was the largest public transit upgrade closure in roughly two decades.

Snowstorms in 2015 forced the aging Massachusetts Bay Transportation Authority to shut down its rail system over 45 weekends to make crucial repairs. Last year, segments of northern California’s Bay Area Rapid Transit system were closed for two weekends so that workers could replace 932 ties and 1,200 feet of rail.

Smaller and mid-sized cities—including Cleveland, Mobile, Alabama and Suffolk, N.Y.—are facing similar challenges addressing their capital replacement needs while maintaining existing service.

According to federal data, between one-quarter and one-third of U.S. public transportation assets are classified as in “poor” or “marginal” condition—largely below the standard of “good repair.”

A significant portion of our nation’s public transit vehicles have outlived their “maximum useful life,” as determined by the federal government, including 31 percent of commuter rail cars and 33 percent of subway cars.  There’s also an urgent need to address aging track, signals, and power sources. Forty-one percent of assets used for bus transport are in subpar condition.

Nationwide, there’s an $86 billion backlog just to bring public transit systems up to that state of good repair.

Absent action, that figure will grow. Local, state and federal governments spend $18 billion annually on capital investments in public transit. But the amount needed to simply repair and maintain our current public transportation infrastructure over the next six years is two-and-a-half times that figure—$43 billion a year.

That’s a problem, given that demand for public transportation is growing. Between 1995 and 2015, public transit ridership increased 37 percent—nearly double total population growth. Over that same period, the number of miles Americans traveled by car increased at a slower pace—just 30 percent.

Public transportation systems can’t accommodate new riders if existing structures aren’t in good condition.

America’s infrastructure woes extend beyond public transport. The American Society of Civil Engineers recently gave the country a D-plus on its Report Card for America’s Infrastructure. The report found that four of every 10 major highways is heavily congested. One in nine bridges has a structural problem.

A miserly approach to infrastructure spending doesn’t actually save money. Drivers waste some $160 billion and 6.9 billion hours sitting in traffic. For the average motorist, that translates to almost two full days idling behind the wheel.

In 2010, poorly maintained public transit systems cost the economy $90 billion in lost time and wasted fuel. That number is expected to reach $570 billion annually by the end of this decade—and more than $1 trillion by 2040.

In other words, our collective refusal to rebuild America’s infrastructure is depriving the economy of hundreds of billions of dollars a year. We can’t afford to watch that money disappear.

Investing in our infrastructure, on the other hand, can add billions to the economy—and enhance America’s competitiveness relative to other nations.

Consider that $1 billion in public-transit investments creates and supports 50,000 jobs in sectors from retail to construction and finance. This increase in employment drives another $3.6 billion in sales for businesses—and some $500 million in federal revenue. Every dollar invested in public transportation generates $4 in economic activity.

As this fall’s election approaches, it’s heartening to hear candidates from both parties talk about America’s infrastructure crisis. But our nation needs action. It’s time to make investments in our infrastructure sufficient not just to address years of deferred maintenance—but to prepare for our transportation future.