Yahoo Finance 
Op-Ed: President Trump—Here's what a 21st century infrastructure plan should look like
If you hop on a train from Baltimore to D.C., you might travel over the Thomas Viaduct, a 180-year-old stone bridge. Pour a glass of water in Chicago or Philadelphia and it might reach you through century-old pipes. Fly into Minneapolis or Albany and you will land at airports initially built in the 1920s, when air travel was new.
The infrastructure America builds in the next few years will define our future for decades, even generations to come. So, it is critical that we focus new investment on the types of infrastructure that will position America well for success in the 21st century.
The United States has different needs today than we did in, say, the 1930s, when the New Deal gave us iconic infrastructure such as the Blue Ridge Parkway and the Hoover Dam. Back then, much of America lacked good roads and access to electricity. The New Deal didn't just put food on the table for the unemployed; it also helped position the nation for 20th century success.
Today, however, rural communities need access to broadband Internet the way they once needed electricity. Cities may benefit more from saving wetlands, forests and other forms of "green infrastructure" than building big new dams. Building the infrastructure to tap the pollution-free energy in wind and sunlight may deliver greater dividends than returning to coal or oil. And we may need modern transit to get across our congested cities more urgently than we need new ways to from coast-to-coast.
What should a 21st century approach to infrastructure look like?
First, it should begin by fixing what we already have. Research suggests, for example, that fixing existing roads delivers greater return on investment than expanding them. But, too often, necessary repairs take a back seat to glitzy boondoggles that afford politicians ribbon-cutting photo ops. A "fix it first" approach to repairing and preserving our existing infrastructure is an economic no-brainer and should take first priority.
Second, our investments should emerge from a clear sense of 21st century priorities. A trillion dollars in infrastructure spending sounds like a lot of money – and it is. But it doesn't go as far as you might think – especially if we first spend what is necessary to fix our existing roads, transit systems, and water systems. Without priorities and criteria for making smart investments, one trillion dollars may quickly disappear into "bridges to nowhere." We need clear vision and the willingness to make tough choices.
And those choices need to be informed by 21st century realities. As America gains energy independence through renewable energy and as more of our neighbors transition from energy consumers to energy producers through roof-top solar panels and windmills on farmland, we need a modern, decentralized, electric grid. As Americans, especially millennials, drive less and less, we shouldn't simply build more and bigger roads, but instead make it feasible for all Americans, rural, suburban and urban, to get where they need to go without relying on a personal car.
Lastly, we need to recognize when building new infrastructure isn't the best solution to a given problem. America often fails to get the most value out of the infrastructure we already have. We spend billions to add more lanes to highways instead of using tools such as pricing and carpooling to reduce demand. This leads to billion-dollar projects like the widening of Interstate 405 in southern California that fail to achieve the stated objective of reducing congestion, instead encouraging more driving, resulting in more long term environmental and public health problems.
We subsidize infrastructure in brand-new exurbs while letting existing urban neighborhoods and first-ring suburbs crumble, as has occurred for decades in many Rust Belt cities. Every piece of infrastructure we build today is one that we'll have to maintain tomorrow, so we need to be smart about getting the most benefit out of everything we build.
The opportunity to rebuild America does not come along every day, and the decisions we make about how to do it will have repercussions for decades to come. With a smart approach to infrastructure, our children and grandchildren can look back with gratitude at the wisdom of our choices. Without one, they will look back in disappointment at the opportunities and precious dollars we wasted.
Commentary by Heather Leibowitz, Esq., director of Environment New York, a statewide advocacy organization.
For the latest commentary on the markets in the U.S. and around the world, follow @cnbcopinion on Twitter.
More From CNBC
