This is an archived article that was published on sltrib.com in 2017, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

President Donald Trump's idea of putting solar panels on a border wall with Mexico, and using the revenue from the energy it generates to finance its construction, is as far-fetched as it is half-baked. Yet a more realistic environmental agenda — one that allows Trump and his Republican allies in Congress to remain true to conservative principles — is not hard to imagine.

Since Trump announced his decision on the Paris agreement, more than 1,000 cities, states and businesses have declared their intention to continue driving down emissions, because they correctly see it as being in their own best interests. (Michael Bloomberg, founder of Bloomberg LP, submitted their statement to the United Nations.) This presents an opening for Trump and Republicans, if they are willing to recognize what it requires: a commitment to the kinds of public transportation projects supported by businesses and cities.

In speaking about infrastructure last week, Trump promised to empower mayors and governors by forming partnerships with them and the private sector. He also promised to slash the regulatory burdens involved in getting projects approved for federal money, which can take a decade. These burdens are often the bane of state and local officials' existence. Other nations have figured out how to build faster without harming environmental or safety standards. There is no reason America can't, too.

Trump wants to reduce the approval process to two years, a worthy goal. Particularly on transportation projects, the economic and environmental benefits could be significant. But therein lies the problem: Trump's executive budget could threaten about $38 billion in mass transit projects, which reduce both the emissions that warm the planet and the congestion that costs the U.S. economy about $124 billion annually.

Mass transit also spurs new private investment that generates economic activity, including new housing construction. That's a big reason dozens of cities in red and blue states have rail projects planned or under way. Not every such project makes financial sense. But on the whole, the country needs more investment in public transportation, not less. Trump's budget also proposes cutting funding for popular local efforts to encourage cycling and walking, both of which also mitigate vehicle congestion and make communities more attractive places for people and businesses.

Making it easier for people to get around town — by train, bus, bike or foot — makes it easier for customers to shop locally. Obstacles to mobility, whether in the form of congestion or isolation from transit options, harm brick-and-mortar stores that are already struggling to stay afloat amid online competition.

Public/private partnerships, together with a streamlined federal approval process, could produce savings that would stretch infrastructure dollars further, but nowhere near far enough to meet the nation's infrastructure needs or to accelerate progress on climate change. That will require new revenue from a higher gas tax, new user fees, or other sources. All of those options require political courage that has long been lacking in Washington, and that, thus far, Trump has shown no signs of possessing.