One of President Donald Trump's first promises after getting elected was to spend $1 trillion on infrastructure—bridges, roads, tunnels, pipes, dams. And whether you've had to evacuate a town in the shadow of a crumbling dam, buy filters for tainted municipal water, or even just bounced over potholes on a highway, you've experienced the problems the president alluded to.

Well, it really is as bad as you think. The American Society of Civil Engineers has just released its latest infrastructure report card, and grades the United States at D plus. That means the country’s public works are in substandard condition, with a risk of failure. The ASCE releases its reports every four years, and the mark hasn't changed since the last time. “While our nation’s infrastructure problems are significant, they are solvable,” says ASCE President Norma Jean Mattei. But that'll take money.

So … $1 trillion, right? Great news! Except the ASCE report says it'll take $4.59 trillion to bring things up to a B, or adequate grade, by 2025. That’s a shortfall of $2 trillion over current spending plans. Again: $1 trillion is nowhere near enough.

Yesterday President Trump had lunch with infrastructure and transport business leaders to start discussing his plans for nationwide rebuilding. As The Wall Street Journal reports, he wants to focus on renovating old roads and building high-speed rail, and he talked about both public and private financing. He even asked Elon Musk for more details about his hyperloop idea. All of which would be a good start but won't fix many of the issues the new report highlights.

Some areas have shown modest improvement since 2013. The 30,000 miles of levees that protect communities and infrastructure along rivers and coasts went from a D minus to a D. Rail went from C plus to B, mainly because freight companies own the majority of the nation’s railroads, and they’ve spent on repairs and upgrades. Passenger rail is still old and underfunded, the report notes—likely no surprise to anyone who uses it.

Now, for sure, be a little skeptical. It shouldn't come as a surprise that a report compiled by civil engineers would call for lots more civil engineering. The worst-case scenario highlights the benefits of expensive, large-scale building projects. Engineers are also ultraconservative, particularly with safety standards (with good reason). But that can lead to exaggerated cost estimates.

Even that aside, infrastructure spending can be a hard sell. Projects take longer to plan, approve, and build than a four-year election cycle. Investments in water supply pipes or levees can often be literally hidden from view. And yet they can be the most critical.

That's where the priority-setting will have to come in. “I’m not just looking at the grade but at what that infrastructure is and how important to safety it is,” says Wassim Selman, president of infrastructure at Arcadis, a global design and engineering consultancy. “Levees are very important because they’re adjacent to communities.” He also highlights dams as a concern. The average age of the 90,580 dams in the US is 56 years, and 2,170 of those are classified as “deficient, high-hazard,” meaning if they fail, it could be very very bad for people living downstream.

All of that means a shortfall in cash money to fix the crumbling bits of the country exactly when federal funding of these mega projects has dropped by half over the past three decades, from 1 percent to 0.5 percent of GDP. So there are two stark choices: Find more money or spend less.

Last November, hundreds of ballot measures asked to raise taxes at the city, region, and state levels to pay for transport projects like light rail and bike paths. And 72 percent of the measures passed. “There’s an aversion at the federal level to raising taxes, but there’s a very different conversation happening outside of the beltway when people are presented with specifics about investment,” says Rob Puentes, president of the Eno Center for Transportation.

Infrastructure could also pay its own way. The ASCE report says one in every five miles of America’s highways is in poor condition, but toll roads like the recently opened 12 miles of I-75 express lines near Atlanta are silky smooth. Tolls could also help fund the structurally deficient 10 percent of America’s bridges, through public private partnerships.

“We can’t afford to make every type of infrastructure a level B,” Selman says. If it's something safety-critical, like hazardous-waste sites or aviation, then of course a good grade is needed. “If it’s just a matter of capacity and level of service, C might be OK.” So parks and recreation (currently D plus) might have to take a back seat, for example.

One positive is that the conversation has moved on from just highlighting the infrastructure issue to attempting to figure out what to do about it. The Journal reports that President Trump wants states to start projects within 90 days of getting cash, so hold on to that thought as you rattle over rough roads and play sardines on the train.